Pressures for hydraulic flat tappet break-in springs

Loves302Chevy

Loves302Chevy

"One test is worth a thousand expert opinions."
Hey Grumpy,
FOR BREAK-IN ONLY - What would you recommend for seat & open pressures for a Crane 114142 hydraulic flat tappet camshaft? With 1.6 rockers, the max valve lift is .512". Would you know of any 1.265" diameter or less single springs that would work with an installed height of 1.700"? I have a new set of VS-380 springs: single with damper, 1.222 OD, .868 ID, 76.84# @ 1.700, 194# @ 1.25", and 1.15" coil bind. What would you use for pressures for after break-in. I plan on using K-Motion #700 springs: (from the K-Motion website) K-700 1.265 diameter single Chrome Silicon spring that is good for camshafts with up to .500 valve lift. 120# @ 1.700 - 375# @ 1.150 - coil bind @ 1.050. Do I need to worry about the extra .012"? I will break the cam in on my engine test stand, and then switch over to the running springs setup. Mike.
 
ideal valve spring pressure for flat tappet cam break-in, short answer,I prefer a spring that has 110-120 lb seat and less than 280 open pressure , for a flat tappet cam break-in but checking the clearances and using a good quality oil and oil additive is critical to durability, Ive used SHELL , and TEXICO DIESEL rated oils, with crane and crower additives very successfully for decades.
but I also coat both the cam and lifters with a good moly base grease during assembly . and use fresh oil and additives and usually a quart of marvel mystery oil added to the mix
most failures I see are related to failures to verify ALL clearances or lack of lots of free flowing lubricant, not a bit more spring pressure!
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pre-spraying all bearing and valve train components with a moly based spray, helps embed micro moly lubricants in the metallic surface micro fissures , a good paste lube like cranes assembly lube over the spray surface helps insure a good lubricant surface coating, that is far stronger than just the ZINC and PHOSPHATES in oil
HERES A FEW OF THE OILS I TRUST, coat flat tappet lifters and cam lobes with crane moly assembly paste lube
crn-99004-1_w.jpg

I usually use 6-7 quarts of oil and 1 quart of marvel mystery oil added in my oil pan 11 quart oil pan and oil cooler system capacity
10W30 Valvoline VR1 Conventional Racing Oil
10W30 Valvoline NSL
10w30 Castrol GTX conventional,
10w30 mobile 1
10w30 KENDAL racing oil
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and heres a good break in additive for flat tappet lifter cams
http://www.summitracing.com/parts/CRO-86092
http://www.acdelco.com/auto-parts/v...engine-oil-supplement-assembly-lubricant.html
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READ ALL THE LINKS BELOW IT COULD SAVE YOU A GOOD DEAL OF TIME AND MONEY
http://www.cranecams.com/uploads/instructions/214e_.pdf

http://www.cranecams.com/uploads/breakin/548e.pdf

http://www.rlengines.com/tech/FlatTappe ... lletin.pdf

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

viewtopic.php?f=52&t=181&p=6764&hilit=erson+break+in#p6764

viewtopic.php?f=52&t=1489&p=3360&hilit=erson+break+in#p3360

viewtopic.php?f=44&t=799&p=1161&hilit=erson+break+in#p1161

viewtopic.php?f=50&t=798&p=1160&hilit=erson+break+in#p1160

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

viewtopic.php?f=54&t=1334&p=2910#p2910

HERES SEVERAL OILS AND ADDITIVES THAT HELP
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CRN-99003-1_xal.jpg

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http://www.summitracing.com/parts/cro-86092/overview/

http://www.summitracing.com/parts/cca-159/overview/

http://www.summitracing.com/parts/cca-1590/overview/

http://www.summitracing.com/parts/tfs-94000/overview/

http://www.summitracing.com/parts/crn-99003-1/overview/

http://www.summitracing.com/parts/bpo-0 ... /overview/

How to Select A Valve Spring


With the many choices of aftermarket cylinder heads, most with "longer-than-stock" length valves, the recommendation of a specific spring for a specific cam is almost impossible. It is now necessary to select the spring that will best fit the cylinder head configuration. We offer the following as guide lines only:

1) "FLAT-TAPPET" cam/lifter applications (Street & Street/Strip) seat pressures

a. Small Block 105-125# Seat Pressure

b. Big Block 115-130# Seat Pressure (Note: Big Block applications need higher seat pressures due to their larger, heavier valves.)

2) "FLAT-TAPPET" Open pressures should not exceed 330# open pressure (sustained after spring break-in) for acceptable cam and lifter life.

a. Open pressures should be a minimum of 220# for applications up to 4000 RPM.

b. For good performance above 4000, open pressures should be at least 260# with stock weight valves. (Light weight valves require less spring open pressure.)

c. Spring open pressures over 280# can cause "pressed-in" studs to come loose; therefore, we recommend screw-in studs for open pressures above 280#.

3) HYDRAULIC ROLLER CAMS require higher spring seat pressures to control the heavier roller tappets and the more aggressive opening and closing rates available to roller cam profiles.

a. Small Block applications: 120-145# seat pressure

b. Big Block applications: 130-165# seat pressure

4) HYDRAULIC ROLLER CAMS use higher open pressures to control the high vertical opening inertia of the heavier roller followers.

a. Small Block applications need at least 260# for general driving applications up to 4000 RPM.

b. Moderate performance small block applications like 300-360# open.

c. Serious small block applications can tolerate 400-425#* open pressures and still expect
"reasonable" valve train life when top quality springs, pushrods, and lubricants are used.

d. Big Block applications need at least 280# for general driving applications up to 4000 RPM.

e. Moderate performance big block applications like 325-375# open pressure.

f. Serious big block performance applications can tolerate 450#* open pressure and still expect "reasonable" valve train life when top quality springs, pushrods, and lubricants are used.

*Note: Open pressures in excess of 360# require the use of roller tappet bodies made of billet steel. Crane hydraulic roller and solid roller tappets are made from 8620 bearing grade steel to withstand the stresses of high-performance use. Most stock hydraulic roller tappet bodies are made of cast iron and cannot tolerate high spring loads.

5) SOLID LIFTER ROLLER CAM/LIFTER
Applications are generally used for serious street/strip use and full competition. Most are not used in "daily-drivers" where day-to-day reliability is stressed. Instead, most of these cams are intended for "winning performance." These cams are designed with "very aggressive" opening and closing rates. High seat pressures are necessary to keep the valves from bouncing when they come back to the seat. In all cases, the valve action and spring pressures required mandate the use of high-strength, one-piece valves.

a. Seat Pressures are determined by valve/retainer weight, engine RPM and life expectancy of components before replacement is required. Milder roller cams require 165# on the seat as an absolute minimum. 180-200# is common for most modest performance applications. 220-250# is common for most serious sport categories and some circle track professional categories. Pro-stock and Blown Alcohol/Fuel drag applications use as much as 340-370# on the seat. (The racers sometimes change springs as often as every 1/4 mile run!)

b. Open Pressures need to be high enough to control the valve train as the lifter goes over the nose of the cam. Ideally, the minimum amount of open pressure to eliminate or minimize
valve train separation is desired. Any excess open pressure only contributes to pushrod flex,
which can aggravate valve train separation. For serious racing applications this can be deter-
mined only by experimentation and track testing. For general guidelines we offer the following:

i. Street/Strip performance with long cam/lifter life desirable, 350-450# open.
ii. Circle track and moderate bracket racing 450-600@ open.
iii. Serious drag racing and limited distance circle track racing 600# and more.

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
 
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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 WILL 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.
btw the best deal I found lately on basic hydraulic flat tappet lifters
http://www.summitracing.com/parts/sum-ht817/overview/

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.

occasionally youll see guys post advice , to remove the inner of the two springs on dual valve springs during the cam break-in process to reduce the lifter to cam lobe load rates, thus reducing the potential for rapid wear during the critical break-in process,the problem I see occasionally is that some guys confuse single valve spring with dampers with dual springs.
typically chevy valve springs use single or dual valve springs usually with an inner friction damper
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single valve spring with friction damper ABOVE
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dual valve springs with friction damper (BOTH PICTURES ABOVE)
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dual valve springs without damper
 
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I have seen the flat-tappet cam & lifter sets that you can buy for an additional cost already "broken in". I would NEVER do this because I have seen for myself that there are differences in engine blocks which would surely cause the cam lobes and lifter faces to have different contact patterns when swapped between blocks. I like the idea of the 1.3 ratio rockers for break-in, but since I already have a "stock" pressure set of new springs, retainers, and locks that will fit in the spring pockets, I will use them for break-in. This gives less pressure not only at valve open, but also at the seat. It's essentially the same as removing the inner springs with a dual valve spring setup. I also do not use valve seals during break-in to make sure the valve guides have plenty of oil available. The heads will have been previously set up with the running springs, taken apart and stored in order in a valvetrain organizer tray. I break the engine in on my test stand for 20-30 minutes and never rev over 3000 rpm. Sure it is more work than the low ratio rockers, but using the test stand is a lot easier than having the engine installed in the vehicle, especially if there are any problems discovered - oil leaks, etc. Then I switch over to the running springs setup, add the valve seals, install the appropriate rpm chip in the MSD 6A, and let her rip. When the engine finally makes it into the engine compartment, then I do an oil change to get the break-in oil out. Mike.
 
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