cast roller cams and high spring pressures don't generally work well

running a cast core roller cam on the street with significantly more than MINIMAL spring pressures for the intended application, IS JUST asking for valve train problems, but a balance must be maintained, if the valve spring is too weak and allows the cam lobe to throw or loft the lifter at...

garage.grumpysperformance.com

sellecting valve springs, and setting up the valve train

How do you determine the spring pressure needed to keep the valves under control for a given lift, duration, and max rpm. It might take you several hours to read thru all the links and sub links but its time very well spent as it could save your engine from destruction and save you thousands of...

garage.grumpysperformance.com

cam wear,articles you need to read

before, you start reading through the thread and links below, Ill point out that I've done the forensics on quite a few failed cams over the years, that guys have brought to my shop and Id say about 60% of the failed cam lobe & lifter problems were traced to a failure to check clearances or...

garage.grumpysperformance.com

http://garage.grumpysperformance.co...mmendation-from-erson-compared-w-crower.4530/

http://garage.grumpysperformance.co...-the-extra-cost-vs-a-flat-tappet-design.3802/

The main reason most solid roller lifters fail in street use, is NOT,
in most cases, the fault of the cams or lifters , its generally related too one of several install, screw-ups

(1) use of very high spring load rates
most people buy solid roller lifters and install them with valve spring load rates,
that are designed to allow 7000-9000 rpm
for some reason, people just seem to think... solid roller, I can reve these into the
stratosphere, stress is cumulative,
if you add 50% more valve spring loads and add a couple hundred, too 2 thousand extra rpm, your tripling or quadrupling the stress

use,and abuse parts they fail, the more abuse the greater the stress,
if the cams were used with the lower valve spring load rates and correct clearances similar to hydraulic roller lifters,
AND used with an ignition reve limiter that kept the engine under about 7000 rpm,
they would have an expected longevity similar to the hydraulic roller lifters
(2)
lack of valve train control, the higher valve spring load rates, generally suggested with solid roller cams,
generally REQUIRE
rocker stud girdles, and better quality valve train parts like rockers, pushrods, retainers etc.
that extra valve spring load rate matched to a more aggressive cam lobe acceleration rate
but with lighter weight roller lifters does put a significant increase in stress on the valve springs, rockers etc.
use hydraulic roller lifter valve spring load rates, limit the rpms to less than 7000 rpm,
and the lighter weight solid lifter actually induce less inertial impact stress
(3)
failure to understand that if you float the valves on a solid roller valve train, your putting extreme stress on the components
(4)
cast core cams will eventually wear, you must run a billet cam core, if long term durability is critical

grumpyvette · Apr 2, 2009

improving cam lobe durability
ALWAYS ask detailed questions as to the best , and most durable parts combination they have available,
for your intended application, from your cam suppliers tech department
keep in mind probably 90% or higher of all valve train problems are not the result of defective parts or materials, in almost every case its a failure to verify valve train clearances or geometry, or lack of correct lubrication, or failing to follow manufacturers directions, or exceeding the intended stress levels or rpm limitations thats the root cause of failures
one factor I will mention is that each manufacturer tends to look at durability, ramp speeds and max lifter acceleration very differently, one reason I tend to prefer CRANE & CROWER is that they both company's in general realize the engine must finish the race to win and a busted valve train is a HUGE problem, they both realize, and design valve train components and cam lobes with DURABILITY and reliable valve control as top priority's that are far more important than squeezing every possible potential HP from a cam lobe design at the expense of long term durability
CAST CAM CORES ARE NOT DESIGNED TO HANDLE OVER ABOUT 130lb SEAT and 400lb OPEN SPRING LOADS ,
YOU NEED A BILLET CAM CORE FOR DURABILITY IF THOSE LIMITS ARE EXCEEDED

READ THIS THREAD
viewtopic.php?f=52&t=6491&p=20681&hilit=spray+springs+cooling#p20681

viewtopic.php?f=52&t=130
viewtopic.php?f=52&t=10182&p=40244#p40244
viewtopic.php?f=52&t=181

viewtopic.php?f=52&t=5931&p=18267#p18267

viewtopic.php?f=52&t=282

viewtopic.php?f=54&t=2187

pictured above you see the last rocked badly out of alignment with the valve center line,
a good example why you need adjustable guide plates, this rocker if left too run off center like this, on the valve stem tip , will quickly destroy the valve guide and rocker

USED LIFTERS TEND TO BE A BAD BET ON CAM DURABILITY
there's several routes you can take here, reducing the spring pressures almost always tends to reduce wear,BEEHIVE valve springs and titanium retainers and light weight roller rockers and valves will allow lower valve train loads. but controlling the valve train in the upper rpm band will limit how far you can go with that as an option, use of a good moly base assembly lube during the break-in process tends to reduce the problems during the lapping in process.
Now it should be obvious that reducing the pressure at the contact point between the lifter and the cam lobe will tend to reduce the tendency for lifter & lobe wear, and increasing the coolant flow at that point helps, so its generally a good idea to remove the INNER spring on DUAL spring valve trains during the break -in process, to reduce pressures while the parts lap in, and a few minutes with some 1000 grit sand paper to remove burrs from the lifter edge sure helps in most cases
you might want to read thru these links
ID prefer to use the hardened steel, cup style, valve spring seats, rather than the inner spring diam. style spring seats, if I have the room with the proper machine work of course.
but those are mostly used with single springs , the inner spring diam. seats

are frequently used with dual valve springs and a damper, so you will be using the matched components depending on existing clearances

or if your into serious mods

READ THRU THIS LINK

viewtopic.php?f=52&t=130&p=728&hilit=erson+break+in#p728

viewtopic.php?f=52&t=3810&p=10200&hilit=+small+base+cams#p10200

http://www.dura-bondbearing.com/Portals ... lletin.pdf

viewtopic.php?f=52&t=788

viewtopic.php?f=70&t=1701&p=4160&hilit=distributor+bronze#p4160

preventing cam & lifter break-in failures

viewtopic.php?f=62&t=1515

viewtopic.php?f=52&t=2166&p=5840#p5840

http://www.nitemareperformance.150m.com/ZDDP.html

http://www.pbm-erson.com/uploads/cat%5B ... CEDURE.pdf

http://www.corvetteactioncenter.com/tech/oil/index.html

viewtopic.php?f=52&t=6198&p=19404#p19404

most flat tappet cams use 110 lb-130 lb seat pressure springs ,
you can get by with the 140 lb-160 lb seat pressure springs in almost every application,
with a roller lifter cam,
but I would have suggested swapping to a billet cam by the time the seat pressure was much over 160 lbs
as the pressure on the lifter roller wheel increases so does the potential for having issues if you match a roller lifter and a soft cam lobe.

but even roller cams can wipe out lobes if the valve train components or valve train lubrication,and geometry is not set up correctly

even roller cams can wipe out lobes if the valve train components, are not matched correctly,
or the spring load rates are not correct, or valve train lubrication, geometry is not set up correctly.
keep in mind the quality of the valve springs and roller lifters is also critical, and if you buy one company's cam and use a different company's lifters or valve springs they don,t recommend in most cases the cam and lifter company's instantly use that fact to VOID any warranty
(not that they can't find a dozen other reasons if they want too!)

keep in mind roller cam wear tends to occur over time, and usually theres obvious signs of wear that indicate things are about to degrade so anytime you get the chance inspect the components for those wear indications as it might allow you to replace defective parts before things get expensive
high spring loads, lack of lube, low oil flow, and the wrong clearances , don,t play well with roller or flat tappet cams over long term use

the slight bevel on the cam lobe and the slight convex surface on the lifter base in combination with the lobe center-line being slightly offset from the blocks lifter bore results in the lifter rotating in its bores as the lobe rotates under the lifter base, if your inspecting a cam for wear make sure the lifters you inspect are replaced on the same cam lobe they were riding on, if you randomly replace them they are very likely to wear much more rapidly and cause a lobe to fail

occasionally I get someone who points out that the roller lifter wheels are not exactly centered on the roller cam lobes , that a function of the original block design being for flat tappet lifters, with flat tappet lifter the lifter bores are purposely not supposed to be in the center. The lifter bores are off center from the lobes and always have been. This was to promote rotation of the lifters, the lobes are slightly tapered and the lifters ran off center. GM did not change the lifter bore spacing when they went to roller lifters

OPTIONS

it should be rather obvious that theres options, cam failures are usually the result of incorrect CLEARANCES or too much SPRING PRESSURE or LACK of ADEQUATE LUBRICATION,USE DECENT MOLY CAM LUBE, and decent quality oil, adding MAGNETS to trap metallic CRUD HELPS, be sure to change your oil filter and oil after the first 3-4 hours or 100 miles as theres bound to be crud and assembly lube trapped in the oil and filter
adding oil flow rates to the cam lifter contact area is one Id recommend in most cases, but without a high capacity baffled oil pan, high volume oil pump and crank scraper that can cause some oil control issues.
the quality of the oil formula has a great deal to do with the effectiveness, newer oils don,t contain the same formula as older oils, the oils rated SL tend to have higher levels of scuff resistance than the newer sm rated oils.
proper valve train geometry tends to reduce wear.
check with your lifter manufacturer as some lifters have oil passages designed to increase oil flow to the contact areas and some don,t. cams get a good percentage of thier lube from oil spraying from the rod bearings or dragged around with the rotating assembly or dripping thru oil return passages from the lifter gallery as well as oil spraying from the lower lifter bore , and cam bearing clearances.

comp cams sells a lifter bore groove tool
http://www.compcams.com/Products/335-353.PDF

Developed by one of the top NASCAR Winston Cup Engine Builders, this innovative new tool precisely grooves the lifter bore to ensure that pressure fed oil is directly injected into the contact area between lifter and camshaft. This increased oiling significantly reduces wear on the camshaft and lifters and decreases the risk of premature failure during break in. This machining operation to the block is quick, easy, inexpensive and is the best insurance for a new camshaft. The replaceable carbide cutters are also available separately. Comes complete with grooving tool, cutter and handle.

Note: The engine must be disassembled to use this tool. cuts groove from .009" to .012".

http://www.compcams.com/Technical/Instr ... es/170.pdf

viewtopic.php?f=54&t=120&p=150#p150

http://www.corvetteactioncenter.com/tech/oil/index.html

viewtopic.php?f=51&t=1458&p=3265&hilit=+magnets#p3265

http://www.hotrod.com/techarticles/engi ... index.html

http://www.pbm-erson.com/uploads/cat%5B ... CEDURE.pdf

http://www.enginebuildermag.com/Article ... ology.aspx

theres also surface hardening and smoothing processes that will tend to limit or almost make wear a non-issue with decent levels of lubrication.

http://www.tincoat.net/coatings/tin.htm ... 5QodzzTt5Q

viewtopic.php?f=52&t=282&p=2022&hilit=moly#p2022

http://www.webcamshafts.com/pages/cam_glossary.html

http://www.mikronite.com/

http://69.20.53.62/faq_camfail.php

viewtopic.php?f=52&t=528

http://www.camcraft-cams.com/index.php? ... m-failures

http://books.google.com/books?id=Yn9F0R ... t&resnum=1

http://www.aa1car.com/library/performan ... etrain.htm

btw on roller cams, roller rockers, and roller lifters and timing chains this stuff works ok as a lube

http://www.summitracing.com/parts/MEL-M-10012

I generally mix some moly assembly lube or that melling assembly lube and MARVEL MYSTERY OIL in a container and dip solid rollers into the mix to soak for a few minutes, before installing them, its not as critical with roller lifters as with flat tappet lifters

very good

very very good

AND /OR

http://www.summitracing.com/parts/CCA-153/

http://www.summitracing.com/parts/MEL-M-10012

grumpyvette · Apr 7, 2009

Roller cam break in
http://www.onallcylinders.com/2015/06/24/roller-derby-how-to-properly-break-in-a-roller-camshaft/

Roller Derby: How to Break In a Roller Camshaft
Posted by David Fuller

By now, it’s common practice (or should be) to use break-in oil with ZDDP or a zinc additive for a flat-tappet camshaft.

But what about roller cams? Any old oil will work for that, right?

According top engine builders, ring manufacturers, and cam grinders, the answer is no. And the reason is pretty simple.

While the rings need to be seated in a roller, an oil that “wears-in” the rings will create a lot of fine metal particulate, and that particulate is a killer for your roller cam. According to Timken, the number-one reason for premature roller bearing failure is particulate contamination. An engine creates more particulate wear metal during break-in than at any other time. In fact the “normal” wear metals for a new engine are up to four times higher than after a engine has finished breaking-in—hence the term “breaking-in.”

So what does this have to do with motor oil?

Quite simply, not all break-in oils are the same. Some break-in oils are designed to accelerate the break-in process, and as a result, these oils generate higher levels of wear metal—bad news for your roller bearings. Other oils are friction modified. The added slipperiness of these oils can prevent the rings from seating properly

Striking the right balance is critical.

Driven BR break-in oil, for example, was formulated to help Joe Gibbs Racing with its engine program. Mark Cronquist, Chief Engineer Builder at Joe Gibbs Racing, says the break-in oil has two jobs: protect the valvetrain and not hinder ring seal.

“With a compacted graphite block and tool steel rings, the materials are very hard, so if the oil is too slippery, the rings won’t seat properly,” Cronquist said. “We still have a valvetrain with roller bearings that need protection as well, so the break-in oil features a high anti-wear formulation without friction modifiers to chemically assist the ring sealing. This strategy reduces the amount of wear metals created during break-in, and that protects the roller bearings in the valvetrain.”

Another aspect of roller cam break-in to consider is the high spring pressures and contact loads the cam, lifters, pushrods, and rockers see. While these loads would spell death to a flat-tappet cam, the high ZDDP anti-wear package of a break-in oil also protects these components during that critical break-in period.

Think of a break-in oil like a primer. Putting down primer before you paint establishes a uniform coating to build from, and that is exactly what a break-in oil does—it establishes a uniform anti-wear film that provides the foundation for protection. Just like a thick coat of primer smoothes out a surface, a properly formulated break-in oil does the same thing. The protective layer of ZDDP anti-wear film smoothes out the peaks and valleys that comprise the microscopic surfaces on the roller wheels and needle bearings. A smooth surface enables greater load carrying with less fatigue.

The more aggressive the valvetrain, the more critical these details become.

“It is hard to fall off the bottom of the mountain,” said Brian Reese from COMP Cams. “The more aggressive the valvetrain is in terms of lift, duration, and spring pressure, the less margin of error you have. The little details become critical.”

According to Reese, using a break-in oil is just part of the equation.

“We are seeing a trend away from flat-tappet engines to avoid the oil issues related to flat tappet cams, but just because you have a roller cam does not mean that it does not have to be broken in properly,” Reese said. “NASCAR level engine programs like Joe Gibbs Racing are still doing a 30-minute break-in on their roller cam engines because they have learned the hard way what happens when they don’t.”

Reese says improper break-in will catch up with you eventually.

“If you get the break-in wrong with a flat tappet cam, it dies right in front of your face,” he said. “If you get the break-in wrong with a roller cam, it may not die until several thousands of miles down the road, but the problem began at break-in.”

Here are a few break-in tips from the experts:

Wash off the rust preventative coating that is on the parts prior to installation. Parts are shipped with a preventative coating, and it needs to be removed for lubricants to function at maximum efficiency.

Apply a calcium-sulfonate grease instead of ZDDP before assembly. While ZDDP is critical in the break-in process, it is not the best assembly lube. After cleaning the camshaft and lifters, apply calcium-sulfonate for protection and lasting lubrication during initial start-up. Then, soak your roller lifters in break-in oil.

Use a finer micron filter during break-in.

Prime the pump before firing the engine. This ensures a critical supply of oil to the cam and lifters at initial start-up.

Do not idle the engine. Bring the engine up to 2,500 rpm and vary the speed by a few hundred rpm for 20-30 minutes.

After a 30-minute break-in, change the oil filter. At this point, you have removed all the larger particles that could cause problems and you can start upping the flow rate of your filter.

Change the oil and filter after initial break-in. Most of the wear metals created by an engine occur during the first hour of operation.

By properly breaking in your roller camshaft, you’ll ensure maximum performance and long life.

Re: improving cam lobe durability

well theres several ways, use of a magnetic base with a dial indicator will allow you to compare each rocker as it moves thru it arc. the intake rockers and then the exhaust lobe readings should all match within a few thousands of an inch

on many hydraulic roller lifter applications a REV KIT on hydraulic roller lifters adds several hundred RPM to the power band before valve control issues develop
read thru these links

http://streetmuscleaction.com/wp-conten ... reakin.pdf

viewtopic.php?f=52&t=528

viewtopic.php?f=52&t=282

http://www.harborfreight.com/cpi/ctaf/d ... umber=5646

http://www.harborfreight.com/cpi/ctaf/d ... mber=93295

visual inspection on a BIG BLOCK is easier than on a sbc, but heres a tool that will help at times

viewtopic.php?f=62&t=881&p=1389&hilit=leakdown#p1389

viewtopic.php?f=27&t=1514

lifter bore center lines on flat tappet cam lobes are offset from cam lobe center lines by design to cause the lifter to spin on its axis, think about it a second, if the lifter and cam axis were perfectly in line the cam lobe would impart significantly less spin to the lifter in its bore, that spin decreases wear.
on roller cams the lobe placement differs to allow the roller to be centered on the cam lobe

http://books.google.com/books?id=Yn9F0R ... t&resnum=1

http://www.enginebuildermag.com/Article ... fters.aspx

HRDP_0606_01_z+flat_tappet_cam_tech+broken_lifter.jpg

If you think you have a worn cam lobe, it will not open the valve completely, while a stuck or burnt valve won,t close completely, remove the compression tester and [color]squirt some oil into the cylinder and retest, if it bumps the readings up significantly its not likely to be a result from a worn cam lobe, but it might be from bad rings, detonation damage on the piston, or a burnt or non-seating valve[/color],
your best course is to pull the valve covers and carefully watch the rockers,and measure the lift at the retainer, with a dial indicator and a magnetic base while you slowly turn the engine by hand if you find a suspect worn cam lobe,when cam lobes wear they usually eat lifters and cause other damage thats measurable at the rocker/retainer

http://www.harborfreight.com/cpi/ctaf/d ... umber=5645

http://www.harborfreight.com/cpi/ctaf/d ... number=623

THERES BILLET AND TOOL STEEL CAM CORES AVAILABLE
http://www.callies.com/wp-content/uploads/2014/06/Cam-Core-Master-Price-Sheet.pdf
Callies Crankshafts Producing 8620 Billet Cam Cores

Recieved notice today, that Callies, is producing billet cam cores for the camshaft industry. This has been in the making for about 1.5 yrs. Since Crane started to have problems, the owner of Callies, took a look at the equipment, but as far as I know only purchased the gear cutting equipment. Crane used to produce the the cams for the aircraft engine mfgs that Callies, makes crankshafts for and when Crane was going down the aircraft engine mfgs notified Callies ,that production of cranks was going to end until a cam mfg was found. So they now mfg and finish cams for aircraft engines and are solving the shortage of cores elsewhere. To me it's good to know that the mfg that makes cranks for aircraft engines also mfg cranks in our market. THEY ARE NOT SUPPLING CAMS ONLY CORES FOR FINISH TO THE CAM GRINDING COMPANYS.

viewtopic.php?f=62&t=881&hilit=leakdown%E2%80%A6

viewtopic.php?f=52&t=282

0810chp_07_z+comp_cams_camshaft_technology_insite_tech+camshaft_valve_events.jpg

If you find a flat tappet lifter that's not pumping oil, you'll need to inspect closer,and try adjusting the preload or lash carefully,flat tappet lifters need to spin freely in their bores to prevent wear,if the cams undamaged (UNLIKELY) yes you can just drop a well lubed (use molly assembly lube)new lifter onto the lobe and adjust the valve preload/ or lash clearance and your good to go, but carefully inspect the cam lobe thru the lifter bore once its out and any resistance to the lifter sliding up out of the bore usually indicates BOTH the lifter base and cam lobe are damaged and you need a new cam/lifter set
then place a high pressure air hose on the cylinder after you bring the cylinder up to TDC on the COMPRESSION STROKE, and listen for air leaking out of the exhaust or intake indicating a burnt or bent valve

why is it that so many of you gentlemen are so reluctant to actually take the time to measure valve train clearance, spring load rates and valve train geometry and make every effort to avoid doing things correctly?
yes it takes some knowledge, some tools and some time, but in the long run its gives you some piece of mind knowing its been done correctly, and your far less likely to have catastrophic engine failures as a result.

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=181

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=2746

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=2661

yes I know your most likely skipping reading thru the sub links, in this and other threads, but thats a mistake that can easily cost you hundreds of dollars and weeks of work you could easily avoid, knowing what your looking at and how and why it functions as it does is critical to long term durability
viewtopic.php?f=52&t=196

viewtopic.php?f=52&t=1376

viewtopic.php?f=52&t=399

viewtopic.php?f=52&t=5902

viewtopic.php?f=52&t=5341

viewtopic.php?f=52&t=4957

viewtopic.php?f=52&t=2746

viewtopic.php?f=52&t=528

viewtopic.php?f=52&t=553

grumpyvette · Apr 30, 2009

Re: improving cam lobe durability

Hydraulic rollers/cams are designed for low maintenance, and the idle to 6000rpm band 90% plus of the engines fitted with them are used in.
the valve spring pressure and resulting load rates are low to provide less stress and wear on parts,
you'll need to think thru your goals here, despite what most cam and lifter catalogs say, hydraulic lifter cams, (EITHER FLAT TAPPET OR ROLLER) seldom maintain valve control nearly as well as a solid lifter cam of similar design,(DUR/LIFT)
now especially with the roller designs that's due to both lower lifter mass and the higher useable valve spring pressures for the solid lifter designs,
but the fact remains that there's a measurable advantage to running solid lifters and matched components once you intend to exceed about 6400rpm.
there's not a darn thing wrong with a hydraulic roller combo, or a solid lifter combo but they are designed in most cases for different power bands, most solid lifter designs assume you'll spend a great deal of your time above 3500-4000rpm plus for a effective power band, while most hydraulic designs are bases on idle-6300rpm or so.
solid roller lifters have gotten a reputation for low reliability on street strip cars but that's not usually the lifter design as much as the excessive spring load rates that are the cause, you can't expect to run two to three times the load rates on a solid lifter cam and not see a reduction in component life expectancy, the secret is to run only enough spring pressure to maintain valve train control, and in many cases a beehive spring and titanium retainer will allow the lighter solid roller lifters to reach significantly higher rpm levels with similar or even lower spring loads than hydraulic roller lifters.
you don't necessarily need excessive load rate springs on a solid lifter cam and lifters if your only spinning it up to lets say 7000rpm, the lighter lifter mass and the solid pushrod seat will generally allow use of springs that will work on a hydraulic roller lifter (beehive springs frequently have advantages) because the lower valve train mass , with the lighter weight solid roller lifters allows a higher rpm limit before valve train harmonics become an issue.

BTW the idea of installing the flat tappet solid or hydraulic lifter cam in a different engine for the break-in process, or swapping a flat tappet solid or hydraulic lifter cam and lifters in an older engine to a new block is FLAWED ,
for the simple reason that the lifter bore angles and spacing MAY BE very slightly different,
maybe only a few thousandths but enough that the lifter to lobe contact areas WILL BE DIFFERENT and as a result there's a slightly INCREASED chance of the lifter lobe wear pattern causing issues once the lifters and cam are swapped between the two blocks, and the second engines started as the contact areas will change between lifter and lobe surface.
and swapping just the used cam and installing new lifters in the new block also slightly increases the risk of inducing wear issues as the new lifters seat on the used cam for similar reasons.
yes swapping new lifters on as used cam if properly done and well lubed is not a exceptionally high risk process , but its generally best to install both parts 9lifters and cam0 with plenty of moly lube and the correct oils and additives and use fairly low spring pressures, many experienced engine builders realize that swapping valve springs is time consuming and fairly difficult so they use a different option, and thats a lower ratio rocker arm.

EXAMPLE, stock big block rockers use a 1.7:1 ratio rocker
heres 1.5:1 ratio BIG BLOCK CHEVY ROCKERS use of the lower ratio rockers during the lifter and cam lobe breaking or lapping in and mating process significantly reduces contact pressures, and wear issues
http://www.summitracing.com/parts/cca-1011-16/overview/

EXAMPLE, stock small block rockers use a 1.52:1 ratio rocker
heres 1.3:1 ratio SMALL BLOCK CHEVY ROCKERS use of the lower ratio rockers during the lifter and cam lobe breaking or lapping in and mating process significantly reduces contact pressures, and wear issues
http://www.speedwaymotors.com/Speedway- ... ,3191.html

just as an example , if your valve springs on a SBC engine are rated at 130 lb seat and lets say 300 lbs open, at max valve lift of .550 and you were to swap from the 1.6:1 ratio you intend to run on the car, too the 1.3:1 ratio rockers during the break in process, you effectively reduce the lifter to cam lobe loads by nearly 1/3rd as the parts lap in, which can easily be the difference between a cam that laps in and lasts or a failed cam lobe or lifter.

grumpyvette · Jul 15, 2009

ISKY CAMS TECH TIPS

Roller Lifters: Keep 'Em Rolling Longer

Most racers are aware of the advantages of Roller Lifters. For those who are not, a brief review is in order. Roller Cams & Lifters are employed today in all-out racing engines where valve lift/area requirements preclude the possibility of employing a flat tappet (solid lifter cam). Higher Lift requires higher valve spring loads (pressures) and flat tappet cams can only handle so much. Additionally, increased rates of lift (cam lobe velocity) above .007" per degree for example on an .842" diameter G.M. lifter, would cause the lobe to reach-out over the edge of the lifters' cam face. Consequently, with either too much spring or too high a lift rate, most racers know that extremely radical flat tappet cams will eventually self-destruct.

But, what about Roller Lifters? Are they as indestructible as many believe? How do we prolong the life of their roller bearings in today's modern race only engines? Roller lifters require special care and maintenance if they are to provide good service life. Here are the 4 most important factors you should consider to insure their success.

1. AVOID DRY "START UP": Roller Lifter Bearings are assembled with a "tacky" rust-preventing grease that is not intended for lubrication. Therefore, new lifters should have their roller bearings thoroughly washed in clean solvent or acetone to completely remove this assembly grease. After air drying, premium motor-oil (non-synthetic) such as Penzoil SAE 25W50 GTP Racing Oil (The best of the mineral based oils) or Amzoil "Red" Racing Oil (synthetic) should be used to pre-lube the bearings just before installation.

2. AVOID "OVERLOAD": Increased load always means reduced service life. Want 50% more thrust from a jet engine? Ask Rolls Royce or G.E. and they'll tell you to expect about Â¼th the service life between overhauls. Similarly, employing drag race valve springs in the 900, 1000 to 1100 lb. Range will reduce the life of your roller bearings between rebuilds much the same as will employing high-impact roller cam profiles.

3. EMPLOY A REV KIT WHEN POSSIBLE: The primary advantage of Camfather Ed Isky's invention of the 1950's is that by pre-loading each Roller Lifter Bearing to its respective cam lobe, you eliminate needle roller bearing "skew". Skewing (the momentary mis-alignment of the bearings' needle rollers to their respective races) is provoked by the start-stop skidding action of the roller bearings each time the lash is taken-up. Eliminate it and you extend roller bearing life dramatically! Unfortunately, many engines such as the Big Block Chevy which could use one the most, don't lend themselves to such an installation because of the severe angularity of the pushrod coming out of the lifter.

4. EMPLOY LIFTERS WITH "PRESSURE-FED" OIL TO THE NEEDLE ROLLER BEARINGS: Hope is a good thing. But hoping oil will eventually find its way to your Roller Lifter bearings is not. Unfortunately, most roller lifters on the market do not pressure feed oil to the needle rollers, depending on the "splash & a little luck" system instead. In contrast, all Isky Roller Lifters feature pressure fed oil to their roller bearings. Isky's Top of the line "Red Zone" Series lifters feature an exclusive 3-Point "Multi-Port" oiling system to constantly bathe the needle rollers with cooling lubrication. Additionally, they feature our famous Marathon Roller bearing with the toughest shock absorbing heavy duty outer bearing race on the market for the highest possible load carrying capability and sustained Hi-Rpm Endurance. And, they're fully rebuildable, making them your best long-term value!

back to top

grumpyvette · Sep 1, 2009

Re: improving cam lobe durability

http://www.summitracing.com/search/?key ... kers&dds=1
(CRANE CAMS USED TO SUPPLY MANY G.M.PERFORMANCE CAMS,
Chevrolet Performance LT4 Hot Cam Hydraulic Roller Camshafts 24502586

this is no longer true and QUALITY has dropped off noticeably by who ever is currently supplying the cams)

there ARE reduced ratio roller rockers designed to significantly lower the lifter to lobe pressures during the cam break-in process, and its a whole lot easier to swap rockers during the break-in process than swap to lower pressure springs or remove inner springs from dual spring valve trains during the break in process, OR YOU CAN AVOID THE WHOLE POTENTIAL, LIFTER/CAM BREAK-IN PROBLEM IF YOU RUN A ROLLER CAM

http://www.youtube.com/watch?v=i_NpzU4p ... re=related

you might want to watch these strobe light pictures of valves at higher rpms

obviously getting the clearances wrong, or over reveing the engine can cause problems

obviously valve float and improper lash clearance can cause problems but in some cases, lash caps can reduce wear

in most cases when you see valve tip damage like this its the result of valve float or a weak valve spring , in many cases youll need to swap to a higher spring load rate and new springs to prevent or reduce this damage
ok after doing dozens of cylinder head valve spring upgrades I have some basic familiarity here. I usually buy valve springs from these guys

http://www.racingsprings.com/Valve Springs/Store/13

it helps if you know what your dealing with before making changes
http://www.racingsprings.com/Store/ProductView.asp?ProductID=228

youll want a spring with about a 130lb seat load and about a 330-350lb open load on most street hydraulic roller cams

the seat can be shimmed to get the installed height loads right and the valve keepers and valve spring retainers BOTH are available in plus .050 type designs so while it might require valve lash caps and longer push rods it is possible to get more retainer to valve seal clearance without major machine work.
I'm reasonably sure you failed to read thru the links

you get real close by using a push rod checker that matches your engine, rocker stud diam, etc.
(btw its upside down in this picture)

the process of finding the correct length push rods not that difficult, you install the correct push rod checker for your application,on a rocker stud, install the adjustable push rod, in place of the stock push rod after roughly adjusting the adjustable push rod to the stock length once the cam is rotated so the lifter, your using to verify the correct length is resting on the cams base circle, and then you extend or shorten the adjustable push rod so the plastic push rod checker just rests on both the tip of the valve stem and the push rod checker as in the picture above, this gets you very close to the correct length, you then use the machinists blue or a magic marker and the rockers you will be using to determine the exact correct length by centering the wear mark on the valve tip as close to the valve stem center line as you can get it.

while it might be initially looked at as an inconvenience,
and while it will take some time and effort youll be amazed at how often,
reading the links and sub-links,
in these threads will allow you to avoid making almost all the more common mistakes guys make,
or even in a few documented cases..a few that required true unique ingenuity,too screw it up so badly
most of us learn by making mistakes or watching the results of the trial and error process made by others...
the key to success is duplicating the successful, work others have done,and it is based
in understanding exactly why things work ,once you fully understand how and why something works you might be able to improve on its function, or the durability.
and
learning too avoid the failures other people have made,
by understanding, how and why they screwed it up.

ACTUALLY READING links WILL help

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=181

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=1376

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=697

links may help

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=1376

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=528

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=1005&p=15534&hilit=spring+shims#p15534

The answer to selecting the proper valve length in relation to the cam lift, and valve spring load rates, depends on the engine valve train geometry and the cylinder head design,
it differs from intake to exhaust on most engines also.
I've usually found longer valves are required if the valve lift exceeds about .630, but theres no rock solid rule, you need to do some research and call your machine shop and the cylinder head manufacture. the load rate also plays a significant part in that decision, thinner valve spring seats, is not always an option, as higher load rates require thicker castings for structural rigidity.
valve lift alone withing reasonable limits, has little to do with the need for longer valves, but as the lift increases the difference between the spring installed height and its spring bind or coil stack obviously changes.
if your standard valve spring has lets say a 1.70 installed height and a 1.20 coil bind or stack height you would generally be looking at .500 difference, subtract the .060 minimum clearance,
added to prevent binding issues for coil bind, that only leaves you .440 useful valve clearance.
now you can machine the heads in the valve spring seat area only minimally as the valve spring seats are over the coolant passages and generally ,
the manufacturers will tell you you can only machine the valve seat so far from the O.E.M. original location,
and in many cylinder heads you can't machine deeper without reducing the heads functional strength or causing problems.
if you can,t machine down into the valve spring seat, your other option is a longer valve stem, or if you just need about .040-.050 maybe you get by with off-set valve locks, or retainers, and longer push rods and valve lash caps.
but most machine shops would prefer the longer valves and longer push-rods to maintain the proper valve train geometry.
valves are generally available . .100,..200, .300 longer lengths for popular engines and you can certainly use a micrometer to measure similar valves from a different engine, if the proper length is not easily available.
be aware that theres both different valve stem diameters, valve lock location, valve lock designs, different intake and exhaust valve steels that you can,t interchange.
one of the old performance tricks some guys used to use on a BBC, engines with turbos, was to replace the 1.88 exhaust valves with 2.00 intake valves from a 430 lincoln engines that were made from exhaust steel.

before as cast

grumpyvette · Dec 24, 2009

Re: cast roller cams and high spring pressures don,t work we

Don't be afraid of doing a retro fit roller conversion to your existing block. The aftermarket lifters are a couple hundred dollars more than the factory roller lifters, but are lighter than oem rollers, and are designed for higher rpms and spring load rates and in most cases lubricate the rollers more efficiently. If you plan to twist some rpm, the retro roller setup may suit you better. And, you save the expense of buying a newer block, and oil pan.

that's valid info, and Id also point out that the SBC O.E.M hydraulic roller ,spider , dog bone,springs and lifter arrangement needs clearance work, and won,t have the proper spring load rates for rpms over about 5900rpm, in most cases , or lifts after about .500 in most cases, and does not work all that well once valve lift exceeds about .550, while the aftermarket lifter designed tend to be more stable.

the stock Chevy hydraulic roller lifters , dog bone and spider springs don,t always work reliably, ALL THE TIME with engines having over .500 lift or when spun over 6000rpm, its not all that rare for the lifter ,retainer to bend the retainer spring allowing the lifter to spin sideways, in the lifter bore, resulting in a destroyed cam, thats why Ive suggested BRAND NAME ,AFTERMARKET RETRO FIT CAM COMPONENTS BE USED

PLUS the fact that ALMOST ALL un-modified factory sbc heads stop flowing well at about .530 lift
KEEP in mind that both the stock cylinder heads(even modified) and standard production block are usually a restriction to your potential power and durability once your looking to exceed about 450-500hp, yes we all know guys who successfully push past those limits but stress is cumulative and its only a mater of time!

http://www.lunatipower.com/Product.aspx?id=2532&gid=310

currently the high rpm lunati hydraulic roller lifters have about the best reputation for durability , but they are expensive
http://forum.grumpysperformance.com/viewtopic.php?f=52&t=181

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=796

the use of factory hydraulic roller lifters is a great idea on a street combo to save money, but once you get more serious its a known restriction to your engines power potential

grumpyvette · Nov 26, 2010

Re: cast roller cams and high spring pressures don,t work we

http://www.lewisracingengines.com/
QUOTE
"My thoughts are I will not use any cast core solid roller in any engine I build.
And unless you have a billet core I highly doubt it is going to live with those pressures.
"I personally think this is not one of the brightest ideas to come from Comp
As for the "endurnot" lifters, there is no way I will run these.
I would give you my personal opinion of them but it would probably be considered "vendor bashing",,, you can read between the lines
Funny thing about Comp "tech" assuming you actually get to one of the real ones.
If you have the exact same lobe done on a billet core the spring pressure recommendations magically seem to go way up & the lifter recommendation changes too

Just like the new Comp rollers that claim to have pressure needle oiling.
What they are doing is the same thing some other manufacturers have done & it is not pressure oil to the axle & needles, it is oil being directed towards the top or the roller edge.
This is an improvement but is not pressure oiling to the needles.
Last time I checked squirting oil at the outside of a rotating object is not the best way to get it to the center of said object,,,,
To the best of my knowledge there are two lifters with true pressure oiling.
One is Isky & the other is Crower with the HPPO option.
Neither are cheap but sometimes you actually do get what you pay for "
this is a cast core roller cam after 10 dyno pulls

BTW if your running a flat tappet cam INSIST ON A P55 core, to have it ground on as they are far more durable than the cheaper cores unless you ask for and pat for the better quality core you get the standard core every time from the big manufacturers, its fully adequate in most cases its just not the best available.
its advisable to order the better core if your looking for max durability and it depends on the cost if its worth it to most guys

grumpyvette · Feb 24, 2011

Re: improving cam lobe durability

some real facts to avoid any misinformation: all hydraulic roller lifters are NOT the same!

1) Morel lifters are not made overseas. They are made in the USA.
they sell only wholesale to vendors and will at times make changes per request provided the volume sold is sufficient to warrant retooling costs

2) Morel does private label lifters for Lunati, Isky, Comp, Bullet and a host of others.
If you can purchase an adequate volume order ,you could have your company logo etched into the lifter for a charge.

3) All the data you read about the benefits of the Morel lifters have been proven and is not internet hype. The lifters have been put through thousands of hours of Spintron testing as well as real world race engine testing. A quality part that does exactly what it is supposed to do, perform well and with decent durability provided the application matches the lifter being used and its intended load and lubrication limitations.

4) not all lifters sold by those company's are made by MOREL
and if your seeing a significantly lower price quoted verify the lifter source as most bargain priced lifters are imports made to lower specs

http://www.lunatipower.com/News.aspx?id=11

http://www.howardscams.com/index.php?op ... &Itemid=37

http://www.crower.com/products/lifters.html?cat=425

http://www.cranecams.com/view.php?s_id=6

Recommended Valve Spring Pressures

Note: The pressure figures given here are guidelines only. Some special applications may require different pressures. When in doubt,

please contact the HOWARD Technical Department ((920) 233.5228)
please contact the Erson Technical Department (800-641-7920)
please contact the CRANE Technical Department(866-388-5120)
please contact the Lunati Technical Department(Tech Line: 662-892-1500)
please contact the CROWER Technical Department(619-661-6477 â€¢)

Hydraulic Flat Tappet Camshaft: 110 lbs Seat pressure / 250-280 lbs open pressure

Solid Flat Tappet Camshaft: 130 lbs Seat Pressure / 300-325 lbs open pressure

Hydraulic Roller Camshaft: 130 lbs Seat Pressure / 300- 325 lbs open pressure

Solid Roller Camshaft

Minimum Safe Pressures)

Up to .600â€ valve lift:

200-235 lbs Seat Pressure / 600 lbs open pressure

Over .600â€ valve lift:

250-280 lbs Seat pressure / 100 lbs pressure for every .100â€ of valve lift

grumpyvette · Sep 6, 2011

Re: cast roller cams and high spring pressures don,t work we

Tech Tip - 2008

Roller Lifters: Keep 'Em Rolling Longer

Most racers are aware of the advantages of Roller Lifters. For those who are not, a brief review is in order. Roller Cams & Lifters are employed today in all-out racing engines where valve lift/area requirements preclude the possibility of employing a flat tappet (solid lifter cam). Higher Lift requires higher valve spring loads (pressures) and flat tappet cams can only handle so much. Additionally, increased rates of lift (cam lobe velocity) above .007" per degree for example on an .842" diameter G.M. lifter, would cause the lobe to reach-out over the edge of the lifters' cam face. Consequently, with either too much spring or too high a lift rate, most racers know that extremely radical flat tappet cams will eventually self-destruct.

But, what about Roller Lifters? Are they as indestructible as many believe? How do we prolong the life of their roller bearings in today's modern race only engines? Roller lifters require special care and maintenance if they are to provide good service life. Here are the 4 most important factors you should consider to insure their success.

1. AVOID DRY "START UP": Roller Lifter Bearings are assembled with a "tacky" rust-preventing grease that is not intended for lubrication. Therefore, new lifters should have their roller bearings thoroughly washed in clean solvent or acetone to completely remove this assembly grease. After air drying, premium motor-oil (non-synthetic) such as Penzoil SAE 25W50 GTP Racing Oil (The best of the mineral based oils) or Amzoil "Red" Racing Oil (synthetic) should be used to pre-lube the bearings just before installation.

2. AVOID "OVERLOAD": Increased load always means reduced service life. Want 50% more thrust from a jet engine? Ask Rolls Royce or G.E. and they'll tell you to expect about Â¼th the service life between overhauls. Similarly, employing drag race valve springs in the 900, 1000 to 1100 lb. Range will reduce the life of your roller bearings between rebuilds much the same as will employing high-impact roller cam profiles.

3. EMPLOY A REV KIT WHEN POSSIBLE: The primary advantage of Camfather Ed Isky's invention of the 1950's is that by pre-loading each Roller Lifter Bearing to its respective cam lobe, you eliminate needle roller bearing "skew". Skewing (the momentary mis-alignment of the bearings' needle rollers to their respective races) is provoked by the start-stop skidding action of the roller bearings each time the lash is taken-up. Eliminate it and you extend roller bearing life dramatically! Unfortunately, many engines such as the Big Block Chevy which could use one the most, don't lend themselves to such an installation because of the severe angularity of the pushrod coming out of the lifter.

4. EMPLOY LIFTERS WITH "PRESSURE-FED" OIL TO THE NEEDLE ROLLER BEARINGS: Hope is a good thing. But hoping oil will eventually find its way to your Roller Lifter bearings is not. Unfortunately, most roller lifters on the market do not pressure feed oil to the needle rollers, depending on the "splash & a little luck" system instead. In contrast, all Isky Roller Lifters feature pressure fed oil to their roller bearings. Isky's Top of the line "Red Zone" Series lifters feature an exclusive 3-Point "Multi-Port" oiling system to constantly bathe the needle rollers with cooling lubrication. Additionally, they feature our famous Marathon Roller bearing with the toughest shock absorbing heavy duty outer bearing race on the market for the highest possible load carrying capability and sustained Hi-Rpm Endurance. And, they're fully rebuildable, making them your best long-term value!

THERES BILLET AND TOOL STEEL CAM CORES AVAILABLE
http://www.callies.com/wp-content/uploads/2014/06/Cam-Core-Master-Price-Sheet.pdf
back to top

lifters , in the block lifter bores , ride on the cam lobes and the dog bone style retainers and those lifter while less expensive, would not be my personal choice.
lift on the valve is controlled by the distance the lifter travels between the cams base circle to the peak lift on the cam lobe, small base cams lift the lifter the same distance as the standard cams, but the smaller base circle allows the cam lobes distance from the cams center-line to be less to provide more cam lobe to connecting rod clearance.
a small base cam may have a .900 inch base circle the standard cams will be closer to a 1.060 but several manufacturers use a 1.125" to 1.150" base circle. keep in mind theres several different cam core materials and heat treatments used by various manufacturers
your cams lift, is the result of the lifter movement, or distance it travels from the cams base circle, where the valves seated, to the point in the cams rotation where the lifters moved along the ramp surface fully up on the nose of the cam lobe where the valves at full lift.
example
lets say in this case we compare two imaginary cams
a standard cams base circle is 1.125" and
your cams running on a .900 base circle
both cams have a .560 valve lift and run with 1.5:1 rockers
so both cams will need to move the lifter .374"
that means the standard cam lobe will be 1.125"+.374" or 1.499" from the cams base to the cam lobe nose
that means the small base cam lobe will be .900"+.374" or 1.274" from the cams base to the cam lobe nose
which is significantly smaller,
small base circle cams are generally only used when connecting rod clearance necessitates there use

will they work? yes they will, but the stock lifter design and spring spider retainer was not designed for lifts over about .530 nor rpms over about 5500 rpm, as always a bunch of research helps long term durability, Ive seen more than once engine have issues using them,and the link bar lifer design is the preferred route.

LESS THAN IDEAL

YES

use of a small base circle cam allows more connecting rod to cam lobe clearance but it also makes the lifters sit a bit lower in the block lifter bores thus the upper edge of the lifter has a bit more chance of lifting the lifter retainer or dog bone keeping the lifters roller centered on the cam lobes.
look at the pictures in these threads I linked , and sub-linked too.

just read the linked info, look at the pictures and ask the cam company you,ll buy the cam from their advise,
on what lifters , and valve springs matched to the cam you've selected and installed, will provide the best long term durability,and valve train stability and make a logical choice, but keep in mind that it gets very expensive very rapidly if your lifter on that cam lobe does not stay in its intended alignment on the cam lobe or the valve spring allows that lifter to loft or float and loose contact with the cam lobe surface at higher rpms

all valve train components made by any and all manufacturers eventually fail or have flaws
the higher the valve spring load rates, and the higher the rpm levels the more stress is induced and the faster wear may occur,
quality control and materials used matters.
sticking to the better name brands, reading and following the instructions, using matched components and checking clearances, use of the correct lubricants at the correct temps and pressure and flow rates, tends to reduce the percentage of failures.
Ill point out that I've done the forensics on quite a few failed cams over the years,
that guys have brought to my shop and Id say about
60% of the failed cam lobe & lifter problems were traced to a failure to check clearances or correct valve train geometry issues , like coil bind, rocker to rocker stud, or rocker to adjustment nut clearance, retainer to valve seal, clearances or rocker geometry, use of the wrong spring load rates for the application ,or failure to check valve train or push rods binding issues like rocker to retainer, push rods binding on guide plates or heads, etc. before they became an issue.
about
10% were traced to failure to remove metallic or other trash, generated by a previous cam failing from the engines internal oil passages, or failure to carefully clean the engine before installing the new cam, and components, ( use of shrapnel screens and magnets help a great deal in this but can,t remove all trash as some is non-magnetic)
5% to low quality components, or miss matched parts, like the wrong spring load rates for the application, and perhaps
15% of the failures due to using the wrong lubricants , or not nearly enough moly cam lube on the lobes and lifter bases or setting up the oil supply system correctly, or use of a high quality oil and filter, and a failure to change that oil and filter regularly after the first few hundred miles , the remaining
1o% were from unknown causes but more than likely due to a failure to correctly break in the cam, or properly adjust the valves before the engine break-in process or carefully check and re-adjust the lifters rapidly during the break-in process
cam quality varies a great deal

http://garage.grumpysperformance.com/index.php?threads/cam-wear-articles-you-need-to-read.282/
http://garage.grumpysperformance.com/index.php?threads/oil-system-mods-that-help.2187/
http://garage.grumpysperformance.co...-the-extra-cost-vs-a-flat-tappet-design.3802/
http://garage.grumpysperformance.co...e-springs-and-setting-up-the-valve-train.181/
http://garage.grumpysperformance.com/index.php?threads/cam-lobe-aceleration-rates.2627/#post-6777
http://garage.grumpysperformance.co...s-on-valve-spring-pressures.10268/#post-41364
http://garage.grumpysperformance.co...k-after-a-cam-lobe-rod-or-bearings-fail.2919/
http://garage.grumpysperformance.com/index.php?threads/block-prep.125/
http://garage.grumpysperformance.com/index.php?threads/using-rare-earth-magnets.15981/

http://garage.grumpysperformance.co...er-lifter-install-direction.11398/#post-52208

http://garage.grumpysperformance.co...ulic-roller-lifter-selection.5522/#post-16620

http://garage.grumpysperformance.co...rect-valve-spring-load-rates.4680/#post-12650

http://garage.grumpysperformance.com/index.php?threads/small-base-circle-cams.3810/

http://garage.grumpysperformance.co...rect-custom-length-pushrods.14241/#post-72353

http://garage.grumpysperformance.co...train-clearances-and-problems.528/#post-57678

http://garage.grumpysperformance.co...cost-vs-a-flat-tappet-design.3802/#post-54090

http://garage.grumpysperformance.co...t-for-specific-applications.10162/#post-40008

http://garage.grumpysperformance.co...ng-pressures-don-t-work-well.1489/#post-36984

grumpyvette · Nov 16, 2011

Re: improving cam lobe durability

540RAT POSTED THIS INFO

Hopefully this will answer most of your questions.

Discussions about running solid roller lifters in BBCâ€™s, is a hotly debated topic. The debate breaks down into two sides. On one side is the traditional needle type solid roller lifter and on the other side is the newer and much higher load rated bushing type solid roller lifter.

Let me say right up front, that I have no agenda here at all. The purpose of the following write-up is only to share the findings that came out of my investigation into needle bearing failures in solid roller lifters. By sharing the results of my investigation, I thought it could help fellow Hotrodders and Racers to make a better informed buying decision. I have only good intentions about sharing this data, because I feel that everyone deserves to know whatâ€™s been going on, and how the two types of lifters compare. I know I would sure want to know, if I was coming into this cold.

Personally, I do not sell lifters, nor do I work for a company that does. So I have no stake in what particular brands or models of lifters are good, bad or questionable. Therefore, I have no stake in what lifters are purchased either. I also donâ€™t care what parts other people run in their motors. Thatâ€™s up to them. The info I provide here is not based on emotion or personal preference. It is simply based on the facts, and followed up with my thoughts based on those facts. Thatâ€™s it, nothing more. Itâ€™s therefore up to the reader to decide if he wants to ignore the info or embrace it.

It is not exactly clear how high the failure percentage is with the needle type solid roller lifters. But these failures have been a significant issue for BBC's, for some years now, and are still happening. Over the last several years, most of my BBC friends, buddies and acquaintances, as well as numerous participants from various Hotrod and Racing Forums, have experienced premature needle type solid roller lifter failures, associated with the needles/axles.

The engine damage has ranged from just the lifters themselves, all the way to major engine destruction, requiring a total rebuild. This is not something new. Among the people I know whoâ€™ve experienced premature failures, it spreads from California to Nova Scotia, and from mild to wild engines. There is certainly more of a potential for these needle type lifters to fail, than there is with any other component inside a BBC. Whatever the true failure percentage is, it is way too high too simply ignore altogether. So, it would be wise to at least take that into consideration when it comes time to purchase a set of solid roller lifters.

Comp Cams has said that the life expectancy of their ENDURE-X solid roller lifter in street driven BBCâ€™s is ONLY 2,000 MILES!!! And those lifters are pressure fed, come with precision sorted needles, and have wear resistant tool steel axles. And in Iskyâ€™s ads for their bushing type EZ-Roll solid roller lifters, they say that with these lifters, youâ€™ll never worry about needle bearing overload or premature roller bearing failure again. And now Crower is following Isky into the bushing type solid roller lifter market. So, all three of these leading lifter manufacturers certainly recognize the fact that needle type solid roller lifters have some serious durability/longevity short comings.

While solid roller setups do make the most power, they can also decrease the valve trainâ€™s life expectancy, compared to what you would generally expect from other types of lifters. Failures of needle type pressure fed solid roller lifters as early as 3,000 to 5,000 miles, or even earlier with street driven BBC Hotrods is not that uncommon. But the earliest single failure that I am aware of, was from a set of Isky Redzones that suffered needle/axle failure at only 1,500 miles in a Street/Strip BBC Hotrod, and wiped out the whole engine.

But some folks think that if they choose the right oil, they can keep their pressure fed solid roller lifters in good shape. But the fact is, that no matter what oil you run, even all the way up to the high zinc/phos Royal Purple XPR Racing Oil (which costs $17.00+ per quart from Summit), your pressure fed solid roller lifters can still fail at a time/mileage that most of us would consider premature. So, even if you use the best oil money can buy, it cannot save you. That's because these lifters typically do NOT suffer from oil related failures (more on that below).

Of course there are some who maintain that pressure fed solid roller lifters donâ€™t experience premature failure, with their owners wondering what all the fuss is about. But reasonable longevity, as a good number of people have found out the hard way, is not guaranteed. Having these lifters reach an acceptable life span, can be just the luck of the draw and not something that you can bet your engine on.

And no matter how well built your engine is. No matter how much valve spring pressure you have. No matter how good your rocker geometry is. No matter what brand of lifter you have. No matter how often you change your oil. No matter what lifter to bore clearance you run (more on that below). At the end of the day, there are only two kinds of pressure fed needle type solid roller lifter users, those who have had premature failures and those who are vulnerable to premature failures. These lifters are absolutely NOT bullet proof.

When I first looked into this issue, the needle type solid roller lifter failures were a very often discussed problem, and no one ever made any attempt to determine what the root cause was. So, I decided to look into it myself for my own reason. And that reason was that I was building a Street/Strip 540 BBC for myself, and I did not want the engine destroyed by failed lifters.

So, a couple of years or so ago, I decided to do a root cause failure analysis, in order to get to the bottom of this all too common premature failure issue. While it is difficult to accurately say just what the failure percentages are, I at least wanted to inspect failed examples and determine why those that had failed, did fail. To that end, I collected a few sets (I would have liked a much larger sampling, but these were the only examples I could get my hands on at the time) of FAILED standard diameter .842" BBC pressure fed, needle type solid roller lifters. These failed lifters were different name brands, and had used different name brands and viscosities of high zinc/phos oils. And they were from different performance level engines, ranging from relatively MILD to relatively WILD.

FACTS FROM THE INVESTIGATION:

The enginesâ€™ specs are:

*** 408ci BBC, 243*/249* duration at .050, .663"/.655" valve lift, .024/.026 hot lash, 210 lbs on the seat valve spring pressure, 567 lbs on the nose valve spring pressure, 15W40 Chevron Delo motor oil, Isky Redzone lifters, 6300 max rpm. These failed at about 3,000 nearly all street miles. This is a relatively mild BBC Hotrod, so failures are certainly NOT limited to only super High Performance motors.

*** 540ci BBC, 266*/272* duration at .050, .678"/.688" valve lift, .016 hot lash, 260 lbs on the seat valve spring pressure, 650 lbs on the nose valve spring pressure, 20W50 Redline motor oil, Crower HIPPO lifters. These started to fail at about 5,000 nearly all street miles. This is a stout Street/Strip BBC Hotrod.

*** 632ci BBC, 277*/292* duration at .050, .848"/.824" valve lift, .026/.028 hot lash, 325 lbs on the seat valve spring pressure, 875 lbs on the nose valve spring pressure, 20W50 Mobil 1, Redline, and Royal Purple XPR Racing Oil, Crower HIPPO lifters, 7200 max rpm. These failed after 1 1/2 years. Mileage and driving style not documented. This is an example of a BBC Race motor.

Careful failure analysis revealed that oiling had played no part what so ever in these failures, but they all had suffered needle/axle failure due to the EXACT SAME root cause â€“ METAL SURFACE FATIGUE FAILURE. This is exhibited by extensive flaking and pitting of the metalâ€™s surface, which is called Spalling. With loose flakes floating around, and the surface no longer smooth and round, the needles can stop rolling and start sliding, thus forming flat spots, which just speeds up the failure process all the more.

This metal fatigue failure comes from excessive loading in general, and from excessive shock loading/hammering in particular. These lifters are way too small for the loads they typically see. And as such, they are a poor design for this application, when it comes to any certainty of a long life. So, it really is not surprising that they are susceptible to failure. After all, jack hammering is designed to destroy things.

And if that isnâ€™t bad enough, I also found that only the 3 bottom needles are in â€œload-bearingâ€ contact when the lifter is loaded down. On top of that, the needles only make a â€œline contactâ€, which means extremely high localized pressure on the needles themselves, as well as on the axle and on the roller ID. And not only had the needles/axles failed, as is normally the case, but the roller OD's, which are also subject to metal surface fatigue failure, had also failed or were starting to fail, depending on the particular set in question. And the larger the lash had been, the worse the lifters had failed.

As for lifter to bore clearance: The smaller the clearance, the more the load is evenly applied across the whole length of the needles, axle and roller wheel, which can help postpone lifter failure a little. And the larger the clearance, the more the lifter can be severely loaded on only one end of the needles, axle and roller wheel, due to lifter sideways tipping. And that just makes this whole problem go from bad to worse, thus accelerating the failure. So, for that reason, Iâ€™d recommend not exceeding .0015â€ lifter to bore clearance with .842â€ lifters.

Spintron testing has shown that the lifters can bounce up and down on the cam's base circle, within their lash slop. So, the larger the lash, the more severe the shock loading/hammering can be, even with proper spring pressures. Because the lifter isn't always going to be in a position to follow the lobeâ€™s clearance ramp as intended, but instead it will hit hard somewhere on that ramp. So all the effort the cam designer put into designing that clearance ramp, will have no effect at all on how hard the lifter hits, at the point of actual contact.

And of course if an engine isnâ€™t built right, and the spring pressures arenâ€™t high enough, Spintron testing has also shown that in this case, the lifters can even bounce the valves up and down off their seats as well. This obviously just makes things go from bad to worse.

So, no matter what Super Duper brand or model of lifter you run, due to this repeated shock loading/hammering, you can still end up with prematurely failed pressure fed needle type solid roller lifters.

After I determined the root cause of these failed lifters, I pulled a brand new set of Crower Severe Duty needle type HIPPO lifters out of my 540ci BBC and put in a set of Isky bushing type EZX's (a particular version of the EZ-Roll design). Hereâ€™s a link:

(http://www.iskycams.com/pdf/2010Catalog-pg28.pdf)

The EZXâ€™s bushings spread the load way out across the axleâ€™s surface, thus greatly reducing the localized pressure between them. Isky states that they have a 350% higher load rating than needle type solid roller lifters. However, even this bushing type of lifter is still subject to roller OD surface fatigue failure, but at least the highly vulnerable needles are gone.

And then there is this statement by Professional Engine builder Mike Lewis (Wolfplace):

Sat Mar 19, 2011 9:53 pm

After about 5 years & at least 75-80 sets personally sold & used, my lifter of choice is the Isky needless ones hands down, if they are in your budget.

If the Isky EZ-Rolls are Mikeâ€™s lifter of choice, you know he has a good reason for saying that.

SUMMARY/SUGGESTIONS:

1. The overall big picture failure percentage is still unclear, but to be on the safe side, I recommend NOT running needle type solid roller lifters, no matter what brand, no matter how expensive they might be, and no matter what their marketing hype says. Because the needles and their axles are by far the most vulnerable to premature metal surface fatigue failure, even if they have high pressure pin oiling. And it goes without saying, to never consider non-pressure fed solid roller lifters either.

Failures with these needle type lifters can include the lifters themselves, the cam, and the blockâ€™s lifter bores. And in the worst case, which is not that unusual, they can wipe out the whole engine, requiring a total rebuild. If you do choose to run needle type solid roller lifters anyway, rather than upgrading to the much higher load rated bushing type, you may well be playing Russian Roulette with your engine. And youâ€™d need to ask yourself, is it REALLY worth risking potential engine destruction, when a far superior, much more durable alternative is readily available?

Clearly the best plan to try and avoid the potential for failure, is to upgrade to the â€œnon-needleâ€ bushing type pressure fed solid roller lifters, which have a much, much higher load rating. A popular lifter of this kind is the Isky EZX bushing type solid roller lifter, as I mentioned above. This lifter is the closest thing to bullet proof that you can get with a solid roller lifter.

2. Try not to exceed .0015â€ lifter to bore clearance with .842â€ lifters. The smaller the clearance, the more the load is spread out and evenly applied across the whole axle, bushing/needles and roller wheel, which can help postpone lifter failure a little. And the larger the clearance, the more the load can be applied to only one end of the axle, bushing/needles and roller wheel, due to lifter sideways tipping, which can drive up localized loading and increase the likelihood of failure.

3. Run the smallest amount of lash that you can live with. Because reduced lash will allow less clearance slop for the lifter to bounce around in. And not being so far out of position on the lobeâ€™s ramp, can help to somewhat reduce the shock loading/bouncing/hammering that the lifters will see, no matter how well that cam lobe ramp is designed.

4. Since you cannot escape metal fatigue failure, it is best to try and replace/rebuild the lifters at frequent enough intervals to head off failure before it catches up with you. But failure intervals are unpredictable and can vary widely, which makes it very difficult to decide on a maximum interval to follow. The most common failure interval that Iâ€™m aware of, not limited just to those I personally inspected, seems to be between 3,000 and 5,000 miles, though itâ€™s not that unusual for them to fail much sooner than that, as mentioned above. With that being the case, personally Iâ€™d never exceed 5,000 miles, as a rebuild/replace max limit.

All you can really do is use your best judgement here. I recommend being on the conservative side, because the engine you might save will be your own. But at least with bushing type solid roller lifters, such as the Isky EZX, all we have to be on the lookout for is roller wheel OD surface fatigue failure, since they donâ€™t use the â€œvulnerable to failureâ€ needles.

5. You could also â€œconsiderâ€ running a rev kit, if that is reasonable for your application. It â€œmayâ€ help a little by keeping the lifter in contact with the lobe. But engines equipped with rev kits, that were still running the normally â€œcalled forâ€ loose lash, have still suffered premature pressure fed needle type solid roller lifter failures. So, that doesnâ€™t really seem to help much.

6. Donâ€™t lose any sleep over what oil brand or viscosity to run, how often to change it, or whether or not it has high or low levels of zinc/phos, because it wonâ€™t make any difference when it comes to metal fatigue failure. Just use your favorite oil and change it at your normal interval. Though running a high quality full synthetic oil with excellent film strength is always a good choice in general.

7. Beyond what is mentioned above, all you can really do is just keep a close eye out for any unusual changes in lash, to try and catch a failure in its early stages, before too much damage is done.

Only â€œhydraulicâ€ roller setups, that don't have such radical lobes, don't have such high spring pressures, donâ€™t see such high rpm, and have no lash, thus no bouncing/hammering/shock loading, seem to have an acceptable record of a good life expectancy on the street, in most cases. So, these are the lifters that really â€œshouldâ€ be used in street driven Hotrods.

But of course a lot of us choose to run solid roller lifters on the street anyway, for the performance capability they provide. But truth be told, this type of lifter is really only intended for race engines. So, we have to deal with their shortcomings when they are used in street driven Hotrods, which is not really the correct application. Because of course, street driven Hotrods see way more time/mileage than race engines ever will.

BOTTOM LINE: Solid roller lifters are very high maintenance parts when run on the street. And to be on the safe side, they will need to be rebuilt/replaced at frequent intervals, when used in that manner. They are probably the weakest link in most street driven BBC engines. And just installing them and forgetting them, can be very risky.

We have generally pushed this nearly 60 year old basic pushrod engine design about as far as we can. And to totally eliminate the potential for lifter failure, weâ€™d need to upgrade to a more modern overhead cam design. But for those of us who still choose to run our beloved traditional BBCâ€™s, weâ€™ll just have to deal with this potential problem as best we can. Thatâ€™s the price we pay for power.

As noted above, opinions and experiences vary on this topic, so everyone will have to make their own decision. But youâ€™ll find the much higher load rated, bushing type Isky EZX solid roller lifters, with a much higher margin of safety, in my 540 BBC.

grumpyvette · Dec 14, 2011

Re: improving cam lobe durability

broken valves,help....
has anyone ever experianced this problem? i got a large cam and springs to match.after market keepers and locks.same stock valves but new,the engine is tuff as hell, totaly rebuilt 355tpi.it runs great until it pops the top off a valve (on the lower of the two grooves on the stem)were the seal goes below the locks.its happened 6 times on random valves.ive been told that the stock valves cant handle the spring rate.and they are snaping off because the presure of the spring when the valve close's is to much because the lift is so much .512/.520 i had the guides machined down so the keepers wont smash the seals.its breaking when the valve closes. do they make after market valves without that lower groove for the seal ? any input would be apreciated.thanx

if your busting valves,or any valve train component you have a valve train clearance or geometry issue your ignoring
its just that simple, yes I'm sure you think everything's great, but if you take the effort to carefully verify ALL VALVE TRAIN clearances and geometry , youll locate the reason why your having durability issues, take the time to find,isolate and fix it, its NOT LIKELY TO BE a valve spring load rate issue, theres no evil sorcerers curse its just a fact that if parts break theres a CAUSE and in most cases its the wrong clearance or a geometry issue or lack off lubrication

read thru this link and sub links

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=181

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=399

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=401

http://forum.grumpysperformance.com...=5931&p=18267&hilit=measuring+pushrods#p18267

grumpyvette · Jun 1, 2013

Re: improving cam lobe durability

"DURATION NUMBERS" WHAT DO THEY MEAN ?
http://www.harveycrane.com/duration.htm

If a statement is made "this cam has 260 degrees of duration", without adding "260 degrees at .050", the duration number of 260 degrees is TOTALLY USELESS!

That's why knowledgeable engine builders usually select a camshaft based on its duration at .05000" cam lift. In addition to being more accurate than "advertised duration", as an indication of a cam's performance potential, duration at .05000" lift applies almost universally, regardless of camshaft make, model or manufacturer.

"DURATION" varies, depending upon WHO wrote the NUMBER!

Using a different timing point baseline in the computation of duration may be more useful in the MARKETING of a camshaft. But most commonly, duration is rated at a nonstandard lift point as a means of enhancing specifications as compared to those of a competitive cam.

As an example, if one company has a popular racing camshaft that has an advertised duration (computed at .01000" cam lift) of 268 degrees, a competitive cam grinder may think that his cam will sell better if it is advertised as having more than 268 degrees of duration. This caters to the "bigger is better" philosophy. Therefore, the competitive cam may be rated at .00700" lift, in which case its duration could be 280 degrees.

At the other end of the spectrum, with cams designed for use in mild street engines a manufacturer may rate its cams at .01300" tappet lift. When specifications of 252 degrees are listed, this will make the cam appear "shorter" (have less duration) than those of the competition.

For mild street applications, less duration is frequently more desirable. So again, by playing the numbers game, a manufacturer can make its line of cams seem more attractive than those produced by other cam grinders.

Another point to consider is that with an underrated advertised duration, a cam will appear to be producing surprisingly more horsepower than an "equivalent" profile from a competing manufacturer. In fact, what you have is not a valid comparison because two cams with similar advertised durations will have considerably different ACTUAL valve timing, if their durations are not computed at the same amount of cam lift.

With all the variations in timing point baselines, making cam duration comparisons can be more confusing than trying to figure who's really doing what to whom in a television soap opera!

When comparing camshaft specifications, the best way to cut through the confusion is to focus on duration at .050" lift and lobe separation. These two figures will provide a solid indication of a cam's performance characteristics.

There are three other specifications that are very important. I call them "HYDRAULIC INTENSITY", "MINOR INTENSITY and "MAJOR INTENSITY". These terms were developed as a means of evaluating a camshaft's BROAD RANGE operational efficiency.

HYDRAULIC INTENSITY may be computed by subtracting duration at .05000" cam lift from duration at .00400" cam lift.

A cam with a duration of 280 degrees @.00400" cam lift and a duration of 220 degrees at .05000" cam lift has a HYDRAULIC INTENSITY of 60.00 degrees.

MINOR INTENSITY may be computed by subtracting duration at .05000" cam lift from duration at .01000" cam lift.

MAJOR INTENSITY may be computed by subtracting duration at .05000" cam lift from duration at .02000" cam lift.

In my personal opinion, the smaller the INTENSITY numbers measure, the performance will INCREASE!

The ideal cam profile would raise the valves to full lift instantly, hold them open for a specified duration and then close them instantly. The laws of physics make it impossible to achieve instantaneous valve opening and closing, but recent advancements in design technology have made it possible to open and close the valves with more area under the lift curve. By so doing, engine efficiency is improved because the valves spend less time at very low lift.

In practical terms, if two cams with similar lobe designs have the same duration at .05000" lift, maximum torque and horsepower will be almost identical. However, the cam with the smaller HYDRAULIC, MINOR or MAJOR INTENSITY figure will have a smoother idle, better off-idle response, superior low speed drive-ability and a broader power curve.

Viewed from another perspective, a lower HYDRAULIC, MINOR or MAJOR INTENSITY number translates to more low end power, without any loss of top end power. It also means that with a highly modified engine, it may be practical to install a cam with slightly longer duration at .05000" cam lift that might otherwise not be practical.

This LOWER INTENSITY solves many complaints of poor idle quality.

State-of-the-art lobe designs therefore, deliver "MORE CAM" per dollar because they produce more power over a wider rpm band.

BLOWN26 · Sep 27, 2013

Lobe intensity numbers

I have a hyd.roller and the hyd.intensity numbers are 68/62 why and what does this do to the to curve compared to a cam with 50/50 numbers

grumpyvette · Sep 27, 2013

Re: Lobe intensity numbers

calculate cam Lobe intensity numbers

DURATION NUMBERS" WHAT DO THEY MEAN ? BY HARVEY CRANE (CRANE CAMS FOUNDER)
http://www.harveycrane.com/duration.htm

If a statement is made "this cam has 260 degrees of duration", without adding "260 degrees at .050", the duration number of 260 degrees is TOTALLY USELESS!

That's why knowledgeable engine builders usually select a camshaft based on its duration at .05000" cam lift. In addition to being more accurate than "advertised duration", as an indication of a cam's performance potential, duration at .05000" lift applies almost universally, regardless of camshaft make, model or manufacturer.

"DURATION" varies, depending upon WHO wrote the NUMBER!

Using a different timing point baseline in the computation of duration may be more useful in the MARKETING of a camshaft. But most commonly, duration is rated at a nonstandard lift point as a means of enhancing specifications as compared to those of a competitive cam.

As an example, if one company has a popular racing camshaft that has an advertised duration (computed at .01000" cam lift) of 268 degrees, a competitive cam grinder may think that his cam will sell better if it is advertised as having more than 268 degrees of duration. This caters to the "bigger is better" philosophy. Therefore, the competitive cam may be rated at .00700" lift, in which case its duration could be 280 degrees.

At the other end of the spectrum, with cams designed for use in mild street engines a manufacturer may rate its cams at .01300" tappet lift. When specifications of 252 degrees are listed, this will make the cam appear "shorter" (have less duration) than those of the competition.

For mild street applications, less duration is frequently more desirable. So again, by playing the numbers game, a manufacturer can make its line of cams seem more attractive than those produced by other cam grinders.

Another point to consider is that with an underrated advertised duration, a cam will appear to be producing surprisingly more horsepower than an "equivalent" profile from a competing manufacturer. In fact, what you have is not a valid comparison because two cams with similar advertised durations will have considerably different ACTUAL valve timing, if their durations are not computed at the same amount of cam lift.

With all the variations in timing point baselines, making cam duration comparisons can be more confusing than trying to figure who's really doing what to whom in a television soap opera!

When comparing camshaft specifications, the best way to cut through the confusion is to focus on duration at .050" lift and lobe separation. These two figures will provide a solid indication of a cam's performance characteristics.

There are three other specifications that are very important. I call them "HYDRAULIC INTENSITY", "MINOR INTENSITY and "MAJOR INTENSITY". These terms were developed as a means of evaluating a camshaft's BROAD RANGE operational efficiency.

HYDRAULIC INTENSITY may be computed by subtracting duration at .05000" cam lift from duration at .00400" cam lift.

A cam with a duration of 280 degrees @.00400" cam lift and a duration of 220 degrees at .05000" cam lift has a HYDRAULIC INTENSITY of 60.00 degrees.

MINOR INTENSITY may be computed by subtracting duration at .05000" cam lift from duration at .01000" cam lift.

MAJOR INTENSITY may be computed by subtracting duration at .05000" cam lift from duration at .02000" cam lift.

In my personal opinion, the smaller the INTENSITY numbers measure, the performance will INCREASE!

The ideal cam profile would raise the valves to full lift instantly, hold them open for a specified duration and then close them instantly. The laws of physics make it impossible to achieve instantaneous valve opening and closing, but recent advancements in design technology have made it possible to open and close the valves with more area under the lift curve. By so doing, engine efficiency is improved because the valves spend less time at very low lift.

In practical terms, if two cams with similar lobe designs have the same duration at .05000" lift, maximum torque and horsepower will be almost identical. However, the cam with the smaller HYDRAULIC, MINOR or MAJOR INTENSITY figure will have a smoother idle, better off-idle response, superior low speed drive-ability and a broader power curve.

Viewed from another perspective, a lower HYDRAULIC, MINOR or MAJOR INTENSITY number translates to more low end power, without any loss of top end power. It also means that with a highly modified engine, it may be practical to install a cam with slightly longer duration at .05000" cam lift that might otherwise not be practical.

This LOWER INTENSITY solves many complaints of poor idle quality.

State-of-the-art lobe designs therefore, deliver "MORE CAM" per dollar because they produce more power over a wider rpm band.

BLOWN26 · Sep 27, 2013

Re: Lobe intensity numbers

So the lower the number the engine gets with it faster an makes more power but why is my cam have have a bigger number (intake compared to the exhaust

grumpyvette · Sep 27, 2013

Re: Lobe intensity numbers

BLOWN26 said:
So the lower the number the engine gets with it faster an makes more power but why is my cam have have a bigger number (intake compared to the exhaust

MouseFink said:
The Cadillac CTS-V lifters, GM-88958689 (box of 16 - $296.36 msrp) will not withstand bone crusing valve spring spressure for long. The Cadillac CTS-V lifters are lighter weight and are no stronger than standard Chevrolet LS-7 lifters, GM-12499225 (box of 16 - $139.76 msrp) or GM-17122490 (box of 8), AC Delco HL-224 hydraulic roller lifters. If you use standard or aftermarket SS valves and valve train components with more than 130 - 150 lb. seat pressure and 330 -360 lb. open pressure, you are better off using hydraulic roller lifters that can withstand that much pressure, such as Comp Cams 875 Reduced Travel or Comp Cams 15850 Short Travel hydraulic roller lifters with restricted oiling.

The Chevrolet LS and Cadillac CTS-V lifters are designed to be used with less than 100 lb. seat pressure and 300 lb. open pressure. That is because instead of bone crushing valve spring pressure, the Chevrolet LS and Cadillac CTS-V engines use titanium locks and retainers with sodium filled and titanium valves. Those lifters also have restricted oiling for moderate load beehive valve springs. Those type valve springs have progressive pressure and do not need to be flooded with oil for cooling. The Chevrolet Z06 and Cadillac CTS-V engines are supercharged and don't need to be be spun up to the stratosphere to make over 500 HP.BTW...You don't have to specify "LS7 lifters" anymore. You can just call them "Chevrolet roller lifters" because GM uses the GM-12499225 (AC Delco HL-124) roller lifters as service replacements in all 1991-2013 V8 engines, except the Cadillac CTS-VR engines.

because intake posts flow rates need to open faster and operate at lower pressures, a piston physically forces exhaust gases out of the cylinder on the exhaust stroke and header scavenging helps drag in the following intake charge in the intake runner but the outside air pressure is what starts the collum of air moving as the piston falls away from TDC on the intake stroke

keep in mind that at 7000rpm a lifter is accelerating and changing direction 116 times each second, and while its only moving about 1/2"--3/4" before reversing direction it weights several ounces, and at that rat of acceleration it requires hundreds of labs of valve spring resistance to force it to maintain constant contact with the cam lobe

Question?
why use stock lifters when there are lots of much better quality hydraulic retro-fit lifters with significantly better potential rpm capability for not much more money? even if you were going to pay $200-$300 more for the linked hydraulic roller lifters, they have a significant advantage in that they don,t tend to have issues with the lifter retention spider or dog bones failing

the aftermarket linked lifters tend to handle valve lifts exceeding about .500 and rpm levels exceeding about 5800 rpm much better and with fewer issues

The main reason most solid roller lifters fail in street use, is NOT,
in most cases, the fault of the cams or lifters , its generally related too one of several install, screw-ups
(1) use of very high spring load rates
most people buy solid roller lifters and install them with valve spring load rates,
that are designed to allow 7000-9000 rpm
for some reason, people just seem to think... solid roller, I can reve these into the
stratosphere, stress is cumulative,
if you add 50% more valve spring loads and add a couple hundred, too 2 thousand extra rpm, your tripling or quadrupling the stress

use,and abuse parts they fail, the more abuse the greater the stress,
if the cams were used with the lower valve spring load rates and correct clearances similar to hydraulic roller lifters,
AND used with an ignition reve limiter that kept the engine under about 7000 rpm,
they would have an expected longevity similar to the hydraulic roller lifters
(2)
lack of valve train control, the higher valve spring load rates, generally suggested with solid roller cams,
generally REQUIRE
rocker stud girdles, and better quality valve train parts like rockers, pushrods, retainers etc.
that extra valve spring load rate matched to a more aggressive cam lobe acceleration rate
but with lighter weight roller lifters does put a significant increase in stress on the valve springs, rockers etc.
use hydraulic roller lifter valve spring load rates, limit the rpms to less than 7000 rpm,
and the lighter weight solid lifter actually induce less inertial impact stress

(3)
failure to understand that if you float the valves on a solid roller valve train, your putting extreme stress on the components
(4)
cast core cams will eventually wear, you must run a billet cam core, if long term durability is critical
SADI = Selectively Austempered Ductile Iron
The only benefit to SADI is cost. That's not to say a SADI cam can't make some power but as the RPM range increases so does the need for a billet cam and more spring pressure. You can lighten the valvetrain and help things out some though.
http://garage.grumpysperformance.co...d-high-spring-pressures-don-t-work-well.1489/
these are both cast core cams (look between the lobes) the dark surface is a flat tappet cam lobe coating, the polished is a roller cam

billet cam cores look like this below

notice the more aggressive cam lobe acceleration rate on the roller cam lobes than flat tappet cam lobes
as a general guide you want to get the valve open to well above the 1/4 of the valve diam. to maximize the potential flow as quickly after TDC as physically possible and hold it open as long as possible if you want to maximize the cylinder volumetric efficiency, but obviously factors like exhaust scavenging and compression and the cars gearing and the need to run well over a wide rpm range preclude, maximizing efficiency in a single narrow power band in most applications

when a manufacturer posts a cams designed cruise or power and rpm range, hes obviously not able to know the application,youll be using it in.
so they generally assume a standard and more common displacement and that youll use parts that will commonly be selected for the application, or they will post some info, stating the cams designed for , lets say 11:1 compression or it will require a 5000rpm stall or other useful info to help you narrow your search, they will generally start with a small block chevy, assume its to be used in a 350-383 displacement, and assume its to be used with a single 4 barrel carb as thats the more common range.
obviously if your building a 427- sbc, or a 302 sbc the displacement and heads and rear gearing etc. needs to be factored into the cam selection process.
in most cases a discussion with the cam manufacturer will help clear things up, but remember some cam manufacturers tend to be focused more on long term engine durability and high rpm valve train stability,rather than looking at MOSTLY at peak power, potential, some concentrate more on maximizing power and pushing the extreme edge of the physical limits on the valve train,stress levels, under the assumption that making a few extra hp, is more important than making the components last longer under the idea that any race engines going to be inspected and refreshed far more frequently.
the more conservative designers figure you need to Finnish a race to win a race and most builders and owners don,t want to constantly be replacing components.
as your engines displacement, compression ratio, port flow rates and other factors, change the objects usually to increase the air/fuel mix volume thats flowing thru the engine and increase the number of power strokes per second, thus its assumed the average rpm range will need to be increased and the low rpm volumetric efficiency is sacrificed, to increase the upper rpm power.
now it should be obvious that a roller cam can be used to provide more lift under the valve lift curve than a flat tappet design, due to simple limitations due to the cam lobe clearance and base circle limitations in most engines,but keep in mind the port design and valve size have a big effect on flow rates
Isky claims that the Comp XE cams violate the 47.5% rule. The 47.5% rule applies to flat tappet cams for SBCs with 1.5 rockers but the concept is still the same for other configurations where the designs are "on the edge" or "over the edge" for lobe intensity. For 1.5 ratio SBCs, the duration at .50 must exceed 47.5% of the total valve lift or your asking valve train problems. For example, take a Comp Cams Magnum 280H, with 230 duration and, 480 lift...230/.480 = 47.9% which exceeds 47.5% therefore would not pose a threat to components. We do not regularly hear about the older, safer HE and Magnum designs rounding off lobes anywhere near as often as the XE cam designs. Unfortunately, some of the Comp Cams XE dual pattern lobes break this 47.5% rule on the intake side so they are likely to be problematic. The design has "steeper" ramps that are too quick for durability and reliability according to other cam manufacturers. They will wipe lobes in a heart beat especially if you have not followed the proper break-in procedure. Other designs are more forgiving during break-in and less likely to fail.

Grumpy · Oct 31, 2021

heres a quote from a well known cam expert who recently passed,
who designed cams for several big name cam manufacturers

and yeah... every time you think you know everything you need to know,
I throw a few more related links and useful info, you need to read...

Links, links and more links!

I'm new here but getting lost in the links and sub links and their links is time well spent. I've recently replaced the blown 305 in my 85 K-10 with a mystery 383, I say that because I don't know it's history. It's an odd build and I would have liked to tear into it more before dropping it in my...

garage.grumpysperformance.com

down the rabbit hole with Alice

grumpy I've been reading info on this forum for a few years now. this forum is by far the most informative , (and at times confusing) Ive found. If you take the time to read the ENDLESS, links and sub links and endless SUB- SUB- LINKS , you can always find what your looking for, but its very...

garage.grumpysperformance.com

Cores.......

The only trouble I have seen with cast iron cores is in the DESIGN of the cores themselves, not the material they are made of. Whenever you have too sharp a radius between the barrel of a cam and a lobe/journal, you can have stress points that cause a cam to break. This has been the major cause of snapped cams in the late 90s, early 2000s. The only good thing was that most of them snapped right in front of the distributor gear, so that the engine stopped firing, but all the valves kept turning correctly. Of course, if a rod hits anywhere on the cam, it'll break, but that's not the cam's fault.....
P55 cores are made by Engine Power Components, I believe they're in Muskegon, Michigan, and they are Comp Cams' major supplier. The P55 cores have a little more carbon on the nose---supposedly 55 Rockwell C, and so resist high valve spring open pressures better. Of course the design of the cam changes everything---Low negative accel on the nose equals well-rounded lobes, which resist high open pressures even better, and high negative accel on the nose equals more pointy lobes, which require harder cams to resist wear.
The $25 surcharge is about $20 profit.....
Steels used in hydraulic roller or solid roller cams are another story.....
The 1st 2 numbers refer to the main alloy, the last 2 to the amount of carbon in the steel. Some common alloys are 8620 and 1050---The 86 means the main 2 alloying elements in that steel are Chrominum and Molybedum---spelling is atrocious--- and the 20 means that there is .20%--That's right, 2/10s of 1% Carbon--Carbon in the steel. This is too low to be hard enough as it is, so 8620 is heat-treated to carburize it. It requires 24 hours or more in a heat-treat furnance to put Carbon .100" deep, and the purpose of the Copper coating is to prevent Carbon from entering where it is not wanted. The Carbon enters only the surface of the lobes and the journals, not the sides or the barrel. Those parts remain tough, and the rubbing surfaces are hard.
On the 1050 steel, the 50 means there is .50% Carbon, enough to be induction-hardened. The depth of heat-treat depends on the frequency of the induction-hardening waves, low frequency pentrates deeper, but requires longer time, newer higher-powered high-frequency induction hardeners give just as hard a heat-treat on the surface, but do not penetrate so deep.
Steels such as 8650/8660 can take very deep heat treats.
Crane, Cam Motion, Andrews, and LSM all use 8620 steel, and this requires them to offer a number of different cores for each engine.
CamShaft Machine Company uses 8660, and this is who supplies Lunati.
Engine Power Components did use 1078, but I am not sure what they use now, as I have not bought from them in the 2000s. They make those Austempered Steel---Cast steel---cores for Comp Cams.
The 1050 is what Ford uses for their hydraulic rollers, and several companies offer that material for the Fords. With proper heat treating it does not require a bronze gear.
Either 8620 or 8660 requires a Bronze gear, as does 1078. Only by using a cast iron distributor gear, such as the EverWear gear, can you get away from Bronze distributor gears for roller cams.
There are also good cores, and crappy cores, available from overseas.

Now I'm wore out.....

UDHarold

cast roller cams and high spring pressures don't generally work well

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The Grumpy Grease Monkey mechanical engineer.