breaking in a new engine combo


Staff member
Cam Break-in Procedure

OK step one you NEVER start an engine with a new cam until you've verified ALL clearances and valve train geometry are correct!
verify the oil and coolant levels are correct and rotate the engine by hand several times to verify nothing binds!
have a running garden hose handy for use in cooling the radiator and having a fire extinguisher handy is potentially a huge help if things go badly!
and you have pre-lubed the engine while slowly manually rotating the crank until all push rods show oil flow,at the rockers and the gauge shows a minimum of 10 psi have you not?
Id watch the coolant temperature and oil pressure constantly, and have checked fuel pressure , carburetor float levels, or fuel pressure in the injector fuel rails and injector resistance.
honestly this takes a good deal longer to post about and discuss that to correct and check, so what ever method you might select ,Adjusting the valves on any new engine as it is a rather simple procedure, that youll need to go thru on almost any new engine instal and you can use the E-O, I-C method,or if your experienced the adjustments easily done at idle speed, your choice, either works just fine if you know what your doing.
Obviously having a timing light and a multi meter handy and having previously verified the timing marks on the damper and timing tab reflect true TDC, is mandatory before you begin the start up process , knowing how to adjust the valves helps a great deal, and you certainly should have long ago verified the cam timing by degreeing in the cam and you dis check the piston to valve clearances, valve train geometry and valve train clearances and rotating assembly clearances
.most guys I know , that are breaking in the rings and bearings and valve train on a newly rebuilt engine, simply stick a garden hose into the radiator and let it constantly overflow onto the driveway , or they fill the radiator and seal it then place a garden hose so it runs water over the radiator outer surface,while the engine, and cam is being broken in, as its a sure way to keep the coolant temps fairly low. so no.there's no reason you can't fill the radiator with water, break in the engine then replace the coolant!, so if you do have a coolant leak your not leaking anti-freeze all over the place, until you get the engine tested and broken in, BTW (be sure all the gauges and sensors are correctly hooked up and working) have a timing light , distributor wrench,and fire extinguisher handy and I usually try to have a dripping wet beach towel handy as its great for quickly smothering carb fires, without the mess a fire extinguisher makes, if you get unlucky and be sure you double check the oil and trans fluid and be sure to fill and bleed the brakes and check power steering fluids also
its the stupid simple stuff that most guys forget!
don,t forget to double and triple check all the fluids levels, is there at least 6 gallons of fresh gas in the tank?,did you put in and check,the fuel filter and check for leaks , verify the fuel pressure regulator works, gauges work?,battery has a full charge? ,engine oil, level, on the dip stick, coolant,level in radiator, brake fluid,bleed brakes, check, transmission fluid , and make sure converters full, verify the tires air pressures good,brake lights work, brakes work,steering works, battery is not loose , have you verified full flawless function of the throttle linkage,and transmission shifter linkage, that fan belts are aligned and tight, lug nuts are tight, u-joint bolts are fastened, radiator hose clamps are tight?, trans coolant lines are tight? got your license and registration, insurance, a cell phone? and some one too tow you home if that's required? ?etc.
have a running garden hose very close by to cool the radiator and a soaking wet beach towel and fire extinguisher in case of a fire related mistake,you'll want a timing light, multi meter and infra-red temp-gun for trouble shooting
its a hydraulic roller cam, and lifter valve train, so your not concerned with the cam lobes, and roller lifters breaking in ,too near the extent a flat tappet cam might be, but obviously the rockers need to be correctly adjusted ,and the rings need time to seat and the transmission needs to wear in, a bit so driving it under load running it up thru the rpm's ranges changing gears will help, and frequent rechecks of fluid levels and temps and an eye on the gauges is always advisable

you might want to read thru this

preventing cam & lifter break-in failures

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













I know some of you gentlemen would rather dig your own eyes out of your face with a rusty fork than read links, sub-links and posted info, but amazingly there useful info , in them, like tools that let you detect cam wear early, when to swap filters
what lubes to use,how to adjust and clearance valve trains, use of magnets to trap metallic crud and limit damage, which filters to use, etc.

the total amount of assembly lube you put on the cam and rotating assembly rarely can exceed 4 OZ and that EASILY fits into an oil filter, so if your getting more crud than the first oil filter traps in the first 30 minutes during the engine brake-in process, logic says its COMING from someplace and a quick look at the filter internals with the tool linked above and the magnets you should have installed should give you a good idea as to the source:thumbsup:

viewtopic.php?f=54&t=120&p=867&hilit=+magnets#p867 ... CEDURE.pdf


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
Ive almost always used about 90% of a good brand of synthetic oil and 10% marvel mystery oil in my engines for MANY years, I generally change both the oil and oil filters in the 3500-5000 mile range and they always come apart during inspections looking like new, what many guys don,t realize is that M.M.O. is just a high quality light oil with a high percentage of solvents and detergents, its not an oil additive in the common sense of the word, just an oil that tends to dissolve crud effectively
... with hydraulic lifters the push rod seat needs to have sufficient slack or clearance to allow oil to fill the area under the push rod seat that's supposed to be supported on a cushion of oil
if you adjusted the valve train with out that oil holding the push rod seat up, the lifter will push very little oil up the push rods to the rockers and will sometimes result in excessive wear like you describe.
THAT'S why IVE always preferred the hydraulic cams be adjusted at idle by backing off the rocker nuts until the rocker clicks and slowly tightening the rocker nut just to the point the clicking stops then adding a 1/4 turn of preload, this allows the lifter to pump up.





you might want to read thru this info and all the sub links first




• Have a high quality service manual available, such as the factory service manual, or the vehicle specific manuals published by Chiltons, Motors, or Haynes. You will need these for the basic information regarding engine disassemble and reassemble along with the torque settings for the various fasteners.

• Read and understand the manual completely, along with these instructions before you begin working. We highly recommend you also have the assistance of a knowledgeable friend to assist you, especially during the initial fire-up and break-in period.

In addition to the normal installation procedure, installing a performance camshaft requires you to check for several extra items to insure long life and optimum performance.

• New Lifters Are A Must- There is no such thing as a good used lifter! Any flat faced lifter establishes a wear pattern almost immediately with the cam lobe it is riding on and cannot be used on any other cam lobe, let alone a different cam. Should you have a need to disassemble the engine, make sure you keep the lifters in order so they go back on to the exact same lobes.

• Valve Spring Pressure and Travel- We highly recommend purchasing the matching valve springs recommended in our catalog. This insures you will have the proper pressures, both closed and open, and sufficient travel to get the maximum rpm, performance and life from your new cam.

• Piston to Valve Clearance- While many performance cams will work just fine with stock pistons, there are many factors that effect your engine and the clearance available. Things such as factory tolerances, normal machine work such as head and block surfacing, aftermarket components such as cylinder heads, higher ratio rocker arms, etc. all effect your engines ability to handle a performance camshaft.

• Valve Train Interference- In addition to valve spring travel and piston-to-valve clearance, a commonly overlooked area is that of retainer to seal clearance. The other common area of interference is rocker arm to stud clearance along with rocker arm travel. The best way to check these is by physically opening both a intake and an exhaust valve on each cylinder head to the gross lift of the cam plus and additional .030". It is easiest to do this by pressing down on the rocker arm with one of the many tools available. Do not simply rotate the engine to the maximum lift point for a given valve. This does not work when engines are hydraulic lifter equipped, or even allow any margin of safety when you are using a mechanical lifter cam.

• Valve Adjustment- The easiest way to insure proper adjustment is to adjust the rocker arms as you install them, one cylinder at a time. Adjust the intake valve as the exhaust valve is just starting to open and adjust the exhaust valve when the intake valve is almost closed. It is simplest to do this with the intake manifold off and watching the lifter’s movement.

• Hydraulic Lifter Valve Adjustment- All engines, regardless of manufacture, require correct valve adjustment. Some engines, such as Chevrolet V-8’s, are equipped with stud mounted rocker arms can easily be adjusted to compensate for changes incurred during engine assembly. Never just torque the rocker arm into place and assume that the lifter pre-load will automatically be correct. Various engine manufacturers use multiple length push rods, shims, and spacers to compensate for changes in pre-load. Hydraulic lifters cannot compensate for all changes. Ideal lifter pre-load is .020" to .080". Do not attempt to fill the lifters full of oil prior to installation. They will fill automatically once started and manually filling them makes adjusting the pre-load a difficult task.

• Mechanical Lifter Valve Adjustment- Adjusting mechanical lifters should be done the same way as outlined above, one valve at a time. For an initial setting, we recommend .003" to .005" than listed on the cam’s specification card. Once broken in and with the engine fully warmed up, re set the rocker arms to the cam’s specification sheet.

• Installation Lubricants- All flat faced (non-roller) camshafts require the use of high pressure lubricant supplied with your Erson cam on the bottom of the lifters, the lobes of the cam and on the distributor drive gear. Do not use this lube on the tips of the pushrods, the sides of the lifters or on the rocker arms. Use a quality oil when installing roller tappets.


• Fill All of the Engine’s Fluids- Using a minimum of a SAE API SD, SE or better fresh clean mineral based oil, fill the engine to the proper level. Do not use synthetic oil during break-in. Fill the coolant system and follow the instructions on purging air from the system. With carburetor equipped engines, fill the carburetor to insure fuel is available immediately. Make sure that the ignition timing is properly set to insure immediate starting, without excess cranking of the engine.

• Pre-Lube the Engine- Using a oil pump priming tool such as those available from Mallory, spin the engine’s oil pump until you see pressure on the gauge or have oil at the rocker arms. Do not attempt to prime the engine using the starter motor!

• Proper Ventilation- Make sure that you do not start the engine without good airflow. That means have the overhead garage door open and the exhaust vented to the outside. If you have any doubts about sufficient airflow to the engine, push the car out of the garage to make sure the radiator can draw in plenty of air. Having a fan to blow fresh air through the garage is a plus.

• Exhaust System- If at all possible, start the car with a muffled exhaust system hooked up and operational. It makes it much easier to hear what is going on.

• Resist the Urge- Take a minute before you try to start the engine for the first time and double check that you are ready to go. Don’t take any short cuts or leave parts such as fan shrouds, air cleaner, wire looms, etc. off. Clean up the are around and especially under your vehicle. Pick up your tools and wipe up the floor so you can easily spot even a minor leak.

• Be Prepared- Have extra coolant or a hose handy, clean rags, tools for tightening clamps, connections, etc. just in case. They need to be in place to make sure you have an uneventful break-in of the camshaft.


• Have a Helper- Now is the time for a helper. They can check the coolant level, check for oil and fluid leaks, and proper operation of under hood accessories. Air pockets in the coolant system are common so make sure the recovery bottle is checked and filled as necessary. You cannot count on the temperature gauge. Temperature gauges are only accurate if the sensor is submerged in coolant and will not give an accurate reading if in an air pocket.

• Do Not Idle the Engine- As soon as the engine starts, raise the rpm to 2,000 rpm. You should also constantly vary the RPM between 2,000 and 3,000 RPM for the first 20 minutes. This is the only way to insure proper lubrication during this critical period since the camshaft to lifter contact area relies almost exclusively on oil splash from the crank and connecting rods. Make sure that you run the engine for a full 20 minutes using this procedure. It will seem like forever, but it is one of the most important steps to insure long, dependable performance.
Ive always smiled when I saw that same instruction, thinking, now how in hell are you going to set the timing at idle when your not allowed to let the engine idle during the cam break-in process, years ago thinking the same question,the answers simple but it takes experience before you realize the answer, you simply set the timing with a TIMING TAPE on the damper at about 32-36 degrees at 3000rpm, and watch the temperature on the exhaust with an INFRARED temp gun,as a guide in almost all or at least most cases, if the exhaust gets cherry red quickly its usually an indicator your ignition timing is retarded or the fuel/air mix is lean,that will be very close to correct when you drop the rpms to 1000 once the cams broken in, after 30 minutes, obviously you need to find TDC during the cam installation and degreeing in process an install a timing tape or use a pre-marked damper, so you can accurately set the timing at 3000rpm

Once Break-in is Complete- Drain and replace the engine oil and filter with new, fresh oil and a new filter. Recheck for any fluid leaks and check all fluid levels. If you installed a mechanical lifter style camshaft, flat faced or roller style, the valve adjustment should be rechecked at this time with the engine fully warmed up. Hydraulic lifter equipped engines should not require any readjustment.

Proper maintenance is important for any vehicle. Frequent oil changes, with a new filter is one of the easiest ways to insure your vehicle will deliver the performance you want for many long happy miles.


MARVEL MYSTERY OIL is a good high detergent oil designed to aid valve train and rings ETC. cleaning, I almost always add about 10% marvel mystery oil to my engines, but if your running flat tappet lifters Id point out that many current oils are designed for roller lifter engines so Id select an oil that's designed for the older design with the higher zinc content, and adding a can of E.O.S. to the oil and moly assembly lube on the lifters and cam, sure won,t hurt on that first break in, if your breaking in the engine in your driveway, have a running hose and a fan handy, water running thru the radiators cooling fins and a fan blowing air helps prevent over heating, have a timing light and USE IT, check your fluid levels and watch your gauges

Print this page out and check off boxes below (in the printed copy) when each step is completed.
Step Box
1) Safety first! If the car is on the ground, be sure the emergency brake is set, the wheels are chocked, and the transmission cannot fall into gear. Next verify that all hoses are tight and that both the radiator and radiator over flow jar/tank are full and have been filled with the proper anti-freeze and water mix.
2) Before starting your engine for the first time, add one pint of engine oil supplement ( EOS¹) to the crankcase oil and then check the oil level. Once this has been done, prime the oil system with an oil pump primer tool. Make sure number 1 cylinder is on TDC compression stroke, and install the distributor.
3) Adjust the distributor timing roughly by hand for a quick start up and smoothest idle possible.
4) When the engine first starts, verify that the engine rpm is at a safe level and that the timing is set near or at 30° before top dead center (BTDC). Run the engine speed between 1,500 and 2,500 RPM’s, varying the engine speed up and down with-in this range, to prevent overheating of the exhaust valves and the exhaust system. This should be done with no-load on the engine and for the first 30 minutes of operation.
5) After the first 30 minutes of the engine running, set the ignition timing according to the timing specifications. Now would be a good time to check thoroughly for leaks.
6) Adjust the carburetor settings, if necessary.
7) Drive the vehicle with varying speeds and loads on the engine for the first 30 miles. Be sure not to use a lot of throttle or high RPM.
8) Run five or six medium-throttle accelerations to about 3,800 RPM (55 to 60 MPH), then letting off in gear and coasting back down to 20 MPH.
9) Run a couple hard-throttle accelerations up to about 3,800 RPM (55 to 60 MPH), then letting off in gear and coasting back down to 20 MPH.
10) Change the oil and filter with recommended oil (10w30SG in most cases) and filter.
11) Drive the next 500 miles normally, without high RPM’s (below 3,800 RPM), hard use, or extended periods of high loading.
12) Change oil and filter again.
13) Your engine is now ready for many happy cruising miles!
Note¹: EOS P/N 1052367 can be used any time during the life of the engine.
Technical Note: This procedure has been corrected and improved from the original GMPP procedure by GILBERT CHEVROLET.

sitting with no air other than the fan moving air thru the radiator is bound to run a bit hotter than on the road, anything under 220F is normal /expected under those conditions.
I run a water hose thru the radiators cooling fins when testing under those conditions., on the street it should run fairly consistently in the 180F-190F range with a 180F T-stat.
in many cases an ADDITIONAL TAURUS electric fan from a salvage yard can be installed on the other side of the radiator to run off a dash switch or sensor that will provide additional cooling when needed.(price varies but its usually very reasonable from salvage yards) ... 1218835261


190F-210F is ABOUT NORMAL,for driving temps, and nothing to worry about, adding a separately mounted TRANSMISSION COOLER if you have an auto trans is usually worth a 10-15 degree drop in the coolant temp,MINIMUM, if the current trans fluids cooled in the lower radiator, adding an 8 qt baffled oil pan is usually good for an additional 7F-10F degrees reduction in oil temp alone
A great deal of the heat is transferred to the oil and trans fluids long before the radiator and coolant sees it,routing the hot trans fluid to an aux cooler and adding a high capacity oil pan significantly reduces the heat the radiator needs to transfer from the coolant to the air flow thru it. ... toview=sku

its been my experience that many cam failures are related to clearance issues or lack of correct lubrication far more than the use of the less than ideal spring load rates.
you might be amazed at the number of guys I see who install valve springs, even shim them to the correct height but never check the retainer to guide clearance,valve seals or valve train geometry, or bother to verify the oil flow thru the valve train, on all 16 rockers
and adding a few of the correct magnets traps almost all the metallic crud from worn lifters and lobes BEFORE it gets into the oil pump



Staff member
ITS HIGHLY RECOMMENDED that you pre-prime the oil sysyem filter and oil passages on a new engine while you rotate it slowly by hand until all the push rods are flowing oil to the rockers.

these oils tested the best, Id strongly suggest the Valvoline racing oils as the best value

10W30 Lucas Racing Only, full synthetic = 106,505 psi
zinc = 2642 ppm
phos = 3489 ppm
moly = 1764 ppm

10W30 Valvoline NSL (Not Street Legal) Conventional Racing Oil = 103,846 psi
zinc = 1669 ppm
phos = 1518 ppm
moly = 784 ppm

10W30 Valvoline VR1 Conventional Racing Oil (silver bottle) = 103,505 psi
zinc = 1472 ppm
phos = 1544 ppm

10W30 Valvoline VR1 Synthetic Racing Oil, API SL (black bottle) = 101,139 psi
zinc = 1180 ppm
phos = 1112 ppm
moly = 162 ppm

30 wt Red Line Race Oil, full synthetic = 96,470 psi
zinc = 2207 ppm
phos = 2052 ppm
moly = 1235 ppm

10W30 Amsoil Z-Rod Oil, full synthetic = 95,360 psi
zinc = 1431 ppm
phos = 1441 ppm
moly = 52 ppm

10W30 Quaker State Defy, API SL (semi-synthetic) = 90,226 psi
zinc = 1221 ppm
phos = 955 ppm
moly = 99 ppm







Big Block Chevrolets have an oil-priming idiosyncrasy. When priming a Big Block Chevy with a drill motor and
priming tool, it is often necessary to prime for as much as 20 minutes (while rotating the engine) to get oil to all
of the lifters and rockers. It is advisable to prime these engines with the valve covers removed so you can
check to see oil coming out of all of the rocker arms before firing the engine. This last step is advisable on all
engines, but particularly on Big Block Chevrolets"


this type above is nearly WORTHLESS




this type bellow works just fine


that idea of the preluber depth limiting collar , added
seems like a good one




I can see a few oil pump primers, made from old distributor bodies, that might not have the necessary length to allow its use.
SBCprimer.jpg ... toview=sku
they are dirt cheap or you can make one from and old distributor

be sure you turn the engine over at least two full turns while applying pressure to and lubing the oil passages to get full access to all the lifters,rockers,bearings etc.

read this ... reakin.pdf

"Why is the first one worthless?"

LOOK CLOSELY, the top primer has no collar to keep the drive shaft centered over the pump so it can slightly mis-align and bind, Ive seen them bend the pump drive if guys get them mis-aligned and just throw a high torque 1/2 drill on and spin them without checking, the lower primer has an alignment collar that tends to keep things from breaking,,yes both have the alignment collar for the manifold but only the bottom one has the lower block support and alignment sleeve that forms the lower oil passage wall, and the drive collar that assure the oil pump drive itself is lined up correctly,keep in mind,the bottom of the stock distributor forms one wall of the main oil passage to one side of the engine, without that passage wall in place you get no oil pressure to one side and darn little to the other due to the HUGE leak the missing oil passage wall presents, the lower distributor is temporarily replaced with that extra aluminum on the lower primer to simulate the correct oil passage config....THATS WHY!
a bit of Vaseline, on a new oil pumps gears will tend to increase the pumps initial efficiency but a decent oil pump primer tool like mentioned above is the correct route to priming an engine


I brazed a 1/2 drive socket on mine so I can use my air ratchet to prime engines as electric drills tend to overheat under low speeds and high loads

you MUST rotate the engine thru two complete revolutions (720 DEGREES)MINIMUM, and SEVERAL TIMES THAT MANY TIMES IS ADVISED before every oil passage in every part is fully seeing the oil flow from the pump! that one lifter/pushrod may be in the part of the 720 degree cycle where little or no oil supply feeds it, try rotating the engine bye hand with a breaker bar slowly, 720 degrees while a buddy applies full oil pressure with the drill on the oil pump primer tool, before worrying about it!a rod driving the oil pump may never build sufficient oil pressure to get oil to the rocker arms, because the distributor shaft forms part of the wall of the oil feed gallery, an oil pump primer tool must look like this, having the lower distributor housing to seal the passage so that pressure can build through the whole system
putting a load on the rings and bearings with no oil flow or oil pressure to replace the assembly lube that's most likely being forced off those surfaces during those first few seconds, and yes for a short time,yes you can do it that way but there is less stress on the engine doing it CORRECTLY by pre-filling all the oil passages and oil filter with oil and getting oil pressure to the bearings the instant the engine starts turning! theres lots of things that you can GET AWAY WITH,WITHOUT OBVIOUS DAMAGE, but doing things CORRECTLY in most cases is by far the better plan,look Im not saying you CAN,T just hit the starter and spin the engine with the coil wire removed till you read oil pressure,BUT, I am saying that there are valid reasons for doing it correctly (PRE LUBE,& prefill the lube passages) that might not show up instantly but do show up under long term evaluation of the results«


The most sophisticated windage tray available today! This exclusive Milodon design features hundreds and hundreds of small louvers that quickly scavenge oil from crankshaft rotation, but prevents reversion common to screen-type windage trays. This is a completely finished, gold irradiated part that does not require additional fitting. And it flat works! Extensive dynometers and on-track testing verifies that Milodon "Diamond Stripper" windage trays out-perform all other screen type trays on the market.
These trays will fit both the Small Block Chevy 350 and 400 main cap bolt pattern. They will also fit right and left hand dipstick engines, as when adjusted properly the dipstick will pass underneath the tray.


32640, #32645

Additional "free" horsepower can be found by the installation of a crankshaft scraper. A scraper will remove any excess oil left on the crank & rods that the windage tray does not remove. Scraper requires fitting to individual crank and rod profile, as well as to engine stroke. Wiper should be fitted to within .045" from rods and .035" from crank counterweights. When installed, scraper is sandwiched between pan rail and block.
Small Block Chevy 32640 \


What do the scrapers bolt to? The pan rails, what do they do?

they either bolt to the block,between the oil pan gasket and the pan or you can weld them to the oil pan rail, on the oil pan,most guys braze or J&B EPOXY THEM TO THE OIL PAN RAIL, no they don,t touch the rotating assembly, you place them and carefully trim them, durring the engine assembly process, so that while you spin the rotaing assembly the teeth miss the outer arc of the rotation by about 1/8" and they are placed on the side of the engine that sees the rotation upwards from the sump, the idea is to restrict oil flow from the sump following the spinning assembly around in the lower block, it helps skim away and restrict oil falling from the upper engine, to remain in the sump area of the oil pan, after the crank assembly sweeps it into the sump.
that way almosrt all the oil makes only a 100-250 degree trip around with the spinning crank a single time, before being forced back into the oil pan.
its NOT installed and used as a source of potentially gaining hp as much as it is a way too insure a steady flow of oil to the oil pump, but it tends to reduce pumping losses that dragging oil around with the rotating assembly can produce.

the combo of these two components and an oil pan similar to this

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.

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

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 ... ,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.





will provide better oil control
Last edited by a moderator:


Staff member
BBC engines have developed a reputation for eating cam lobes because most guys either don,t break the cam in correctly or are not willing to make the mods necessary to supply the extra oil flow that prevents oit from HAPPENING with the INCREASED PRESSUREs aftermarket cams with thier higher lift, durration,ETC. and springs produce, 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 1000grit sand paper to remove burrs from the lifter edge sure helps in most cases
first ID strongly suggest a high voluum oil pump and a windage screen with a baffled high voluum pan,
use the solids with the extra oil bleed hole that feeds oil to the lifter/cam lobe contact area (pr107)


both crower and comp cams sell them, but they are fairly expensive compared to standard solid lifters, I tend to use them when I can get them but it might be overkill on the oil flow to some extent because I use this tool too put a slight groove in the lifter bores that constantly sprays oil onto the cam lobe at a point just before it rolls under the lifter base

if youve adjusted the valves correctly the lifter spins at all rpm levels,but that does NOT mean it wears EVENLY at all rpm levels due to several factors if you look closely AT FLAT TAPPET CAMS , youll see that the center of the cam lobe is NOT centered under the lifter and that the lifter surface is slightly angled , BOTH these factors force the lifter to spin in its bore as the lobe passes under the lifter slightly off center.

SOME of the reasons the higher rpm durring the break in phase is important is that

(1) the faster RPMs the better chances the lobe passes under the lifter floated on an oil film and the less time the oil film has to squeeze out between them

(2) the higher the RPM the greater the oil voluum and pressure the engine pumps and the more oil flow is available at the lobes

(3)the higher the rpm level the more oil is thrown from the rods onto the cam lobes

(4)the higher the rpm the greater the lifters weight and inertia tends to compensate for the springs pressure and lower the net pressure as the lifter passes over the cam lobes nose

(5) at higher rpm speed the better chance a small wedge of oil is trapped between the lifter base and lobe from the oil thrown from the lobes surface by centrifical force

(6) two differant metal surfaces scraping past each other at low speeds may tend to wear and GALL as the oil is sqeezed out but two differant hardness steel surfaces that impact each other at higher speeds covered with oil tend to work harden as they mate and will tend to be seperated by that oil

(7)as the lifter spins in its bore the contact point between the lobe and lifter base constantly changes and rotates with the lobe contact point not resisting its passage and the higher the rpms the faster the lifter rotates and the less time the lobe spends at any one point

BTW ADD E.O.S. to the oil and MOLY break-in lube to the cam
before starting the engine and prefill the filter and pre-prime the oil system before starting the engine.
I normally pour it in just before starting the engines cam break in,procedure. because I want to make sure that nothing in the oil/E.O.S. mix can settle out from sitting over a long period of time. now if your running a flat tappet cam you should have also used a moly cam lube on the lobes and be useing a mineral base oil for the break-in procedure, and youll need to do an oil and filter change after about the first 3-4 hours running time to remove that moly cam lube from the engine after its served its purpose of protecting the cams lobes and lifters at start up, aND AS THE LOBES/LIFTERS LAPPED IN. MOSTLY to prevent that moly grease and E.O.S from potentially partially clogging the filter after that mix cools down,but also because both those lubes might leave deposites in the combustion chamber ,over time that might aggravate detonation.
even G.M. suggests that E.O.S. is not a great long term oil suppliment, and that its main function is to add extra oil film strength durring new engine break in.

EOS - Engine Assembly Prelube<BR>Specifically formulated as an engine assembly lubricant. E.O.S. provides outstanding protection against run-in wear and piston scuffing as well as run-in camshaft lobe and lifter scuffing resulting from insufficient lubrication

don,t forget a few magnets in the oil pan goes a long way towards trapping unwanted metalic dust formed from the cam and rings lapping in durring break-in that might otherwise get imbedded in your bearings or cause other problems
heres the magnets I use in every engine

if the cam and lifter break-in failed during the cams break-in,
theres a very good chance you have a clearance or valve train binding issue some place like spring bind or rocker to rocker stud or the wrong valve train geometry
reading the links and sub links will save you a great deal of problems
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Staff member
BTW, It should go without saying it but Ill post this bit of info anyway, theres an oil pump drive shaft connection between the oil pump drive and the lower distributor, theres a blade/slot type connector at both ends of the shaft and the shaft length should allow there to be about .030-.050" of vertical play or slack in the shaft when the distributors seated and clamped in place and the oil pumps firmly bolted with a stud to the rear main cap,the stud lower end should NOT touch the rear main bearing shell and ideally youll use loctite on its course thread section in the main cap.
theres several designs and several lengths on these oil pump drive shafts.

the correct oil pump primer tool duplicates the distributor body and seals the oil passages
just a tip guys, any ELECTRIC DRILL is going to have a difficult time spinning an oil pump priming tool , without heating up and at least potentially or eventually burning out ,simply because electric drills cool with air flow and spinning as slow as an oil pump priming tool with that much resistance to the rotation its not going to be spinning fast enough to get the required air flow to cool properly.

there IS a simple solution for anyone who can fabricate that has access to air tools
you simply modify an old distributor similar to this picture then weld on a 3/8" drive socket to the top and your your AIR RATCHET to spin the primer tool which will not overheat and burn up.

the ARP and MELLING design drive shafts with the reduced diam. mid shaft are far stronger than the stock style, and the reduced diam. aids clearance on the larger dia. 400 style crank engine blocks with their larger diam. main bearings, the steel collar that mates to the oil pump slot drive is far stronger than the nylon sleeve found on some on stock drives ... toview=sku ... toview=sku

this style
bellow works ok in the 350 base engines but won,t always clear in the 400 blocks ... toview=sku

many guys don,t realize the oil pump drive shaft design is why the distributor will only fully seat on the intake in the two locations 180 degrees apart and that you need to index the drive before seating the distributor to get the rotor to point where you want it too.
If you use a nylon sleeve/collar, its not unheard of for the slot drive to break off a part and the pump to spin erratically at low rpms or fail to spin at high rpms, so verifying its the correct length, not binding, and in good condition, rather than just assuming its correct is smart, and BTW the steel collar prevents the shaft from being installed from the top of the block, you need to install the pump with the shaft attached from the lower block,if you forget don,t get stupid and cut off the collar and drop it in from the top, it will work temporarily but it almost always fails eventually if you do. ... kers&dds=1

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
grumpyvette said:
Cam Break-in Procedure

Fill the coolant system and follow the instructions on purging air from the system.

OK, I'm stumped. I searched on "purge" and did not find anything on purging the cooling system. My 1961 shop manual doesn't mention it either. How do you do this?



Staff member
brad.arcova said:
grumpyvette said:
Cam Break-in Procedure

Fill the coolant system and follow the instructions on purging air from the system.

OK, I'm stumped. I searched on "purge" and did not find anything on purging the cooling system. My 1961 shop manual doesn't mention it either. How do you do this?


on the latter year corvettes theres a air purge valve, on the coolant system, and a procedure,to follow, but on a 1961 that's simple, you park the car with the front wheels on ramps and loosen, temporarily remove the radiator cap , start the engine and let it idle until you see coolant flowing thru the radiator , it really helps if you've drilled about 6-8 holes in the t-stat flange so air can,t be trapped, once you see coolant flow consistently put the radiator cap back on tight, your done

read thru this thread

if you don,t drill the t-stat flange youll need to wait for the t-stat to reach operating temp to pass air trapped in the system, and adding the holes tends to keep the engine temps far more consistent, I can,t for the life of me understand why the factory doesn,t manufacture t-states with at least three 1/8" holes in the flange, minimum, and yes it tends to slow the engine reaching operational temps for a minute, or two longer and that might increase emissions during that minute or two,but it also tends to increase the engines dependability
Got it; thank you.

I paid good money for this flat tappet cam crate engine and I REALLY want to get it right. Another dumb question: the brochure from the builder says to set the initial timing at around 1000-1200 rpm, (no vacuum advance on this engine ever) at 13-16. It also says on initial startup and for the 1st 20 min not to go below 1500 RPM, preferably not below 2000 RPM.

So, how do you resolve the dilema of setting the timing at 1000 RPM but not not letting the RPM go below 1500-2000 RPM during initial startup and cam breakin?



Staff member
Ive always smiled when I saw that same instruction, years ago thinking the same question,the answers simple but it takes experience before you realize the answer, you simply set the timing with a TIMING TAPE on the damper at about 32-36 degrees at 3000rpm, and watch the temperature on the exhaust with an INFRARED temp gun,as a guide in almost all or at least most cases, if the exhaust gets cherry red quickly its usually an indicator your ignition timing is retarded or the fuel/air mix is lean,that will be very close to correct when you drop the rpms to 1000 once the cams broken in, after 30 minutes, obviously you need to find TDC during the cam installation and degreeing in process an install a timing tape or use a pre-marked damper, so you can accurately set the timing at 3000rpm

read this thread

grumpyvette said:
ITS HIGHLY RECOMMENDED that you pre-prime the oil sysyem filter and oil passages on a new engine while you rotate it slowly by hand untill all the pushrods are flowing oil to the rockers.

OK, I've never done this before so I have another dumb question. I'm priming my new crate engine now (about 5 minutes so far) that hasn't been turned over in more than a year. I'm getting oil only on the driver side rockers, none on the passenger side. I know that I'm supposed to turn the crank while I'm priming but I was going to wait until I saw oil on both sides before turning it.

I don't know exactly how the oil gets to the lifter passages; does the cam have to turn to to align with something? Since I haven't turned the crank at all, am I blocking oil flow to the passenger side valve train?

Should I prime more and wait for oil flow on the passenger side or should I go ahead and turn the crank even though there's no oil on the that side?



Staff member
if you read further up in this thread it points out that if your not using the correct style of oil priming tool that seals off the oil passages youll NEVER get oil pressure on BOTH sides of the engine, because the lower part of the priming tool or distributor needs to be in place or the oil passage on one side has a huge leak, as one side of one oil passage is not sealed

btw, if you braze or weld a 1/2 drive socket to the top of your oil primer tool you can use the 1/2" drive air ratchet
to prime the engine instead of burning out expensive electric drills working under high torque and low rpm conditions where they quickly overheat and burn out
Thanks, you caught me not reading all the fine print. I bought the "better" tool but then I compared the length from the bottom of the lower collar to the tip with the same dimension on my distributor; about 3/8" longer! So, even though the collar's there, it's too far up.

I'll cut it down tomorrow and try again.

You can actually see the longer length on tool I bought on the left to that of a different brand; both from the same catalog.


Turned out to be too much work to modify the tool; bought a new one instead, the one with the correct dimensions. Hopefully I can get a refund for the POS. Got oil pressure on BOTH sides today. Turned the crank by hand a few times, checked that none of the valves are stuck and turned the crank a few more times to measure runout on my bellhousing.



Staff member
reading the links , sub links and fine print,as you travel thru this hobby almost always pays off in the long run


Staff member
use of the best friction reducing MOLY assembly lube plus the better oils, helps reduce cam lobe wear issues

proper clearances ARE MANDATORY
Moly Basics
Molybdenum Disulfide


Molybdenum is a very hard metal with a number of industrial uses.
It is combined with chromium in steel to make the steel harder and more resistant to bending. Most of the bicycle frames produced today use chromium and molybdenum steel. Because the steel is so much harder, the manufacturers can use less, thereby making the frame lighter.

Molybdenum Disulfide (Moly) has been used for decades in lubricating pastes and greases because it is slippery and forms a protective coating on metal parts.

Moly exists as microscopic hexagonal crystal platelets Several molecules make up one of these platelets. A single molecule of Moly contains two sulfur atoms and one molybdenum atom. Moly platelets are attracted to metal surfaces. This attraction and the force of moving engine parts rubbing across one another provide the necessary thermochemical reaction necessary for Moly to form an overlapping protective coating like armor on all of your engine parts. This protective armor coating has a number of properties that are very beneficial for your engine.


The Moly platelets that make up the protective layers on your engine surfaces slide across one another very easily. Instead of metal rubbing against metal, you have Moly platelets moving across one another protecting and lubricating the metal engine parts.

This coating effectively fills in the microscopic pores that cover the surface of all engine parts, making them smoother. This feature is important in providing an effective seal on the combustion chamber. By filling in the craters and pores Moly improves this seal allowing for more efficient combustion and engine performance.

This overlapping coating of Moly also gives protection against loading (perpendicular) forces. These forces occur on the bearings, and lifters. The high pressures that occur between these moving parts tend to squeeze normal lubricants out.

Eventually, there is metal to metal contact, which damages these moving parts and creates large amounts of heat. Fortunately, this is not the case with some lubricants.The layer of moly that forms on these moving surfaces can withstand pressures of 500,000 psi, without being squeezed out.

Engineers and scientists have tried for years to use Moly in motor oils but they had been unsuccessful because they could not find a way to keep Moly in suspension. Once Moly was put into suspension it would gradually settle out. It was easy to see it come out of suspension because a black sludge would collect on the bottom of the oil containers. In engines it would settle to the bottom of the crankcase or clog oil pathways and filters.

Engineers have overcome these obstacles. They have developed a process that keeps Moly in suspension and isn’t filtered out. Since that time theproduct has undergone extensive independent testing in labs and in the field for many years to insure that the product stands up to the rigorous needs of today’s engines. With the plating action of Moly reducing friction which reduces heat, this helps keep rings free from carbon buildup, prevents blow-by, decreases emission, and extends oil life.
ASSEMBLY LUBE USED ON CAMS AND LIFTERS ROCKERS< BEARINGS ETC. like CRANE CAM LUBE, has molybdenium disulfide in assembly lube, that helps maintain a strong heat resistant high pressure lubricating support film on sliding surfaces, BUT assembly lube is NOT INTERCHANGEABLE WITH MOLY AXLE GREASE
which has other ADDITIVES, in some cases its mixed with non-compatible lithium grease base,
you must use a moly based assembly lube thats designed to mix with automotive oil to provide a strong surface film on sliding surfaces



The Moly platelets that make up the protective layers on your engine surfaces slide across one another very easily. Instead of metal rubbing against metal, you have Moly platelets moving across one another protecting and lubricating the metal engine parts.


MOLY adds a great deal of lubrication to sliding metal surfaces , as it embeds in the micro fissures in the metallic surface's


This coating effectively fills in the microscopic pores that cover the surface of all engine parts, making them smoother. This feature is important in providing an effective seal on the combustion chamber. By filling in the craters and pores Moly improves this seal allowing for more efficient combustion and engine performance.

This overlapping coating of Moly also gives protection against loading (perpendicular) forces. These forces occur on the bearings, and lifters. The high pressures that occur between these moving parts tend to squeeze normal lubricants out.
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