How to prep and start a rebuilt engine

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by: Cobalt327
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[edit] Engine assembly

[edit] Bearings

Michigan (of Michigan bearings) sells a bearing assembly lube (blue, consistency like thin syrup), it's good for use on cam and crank bearings and journals. But 30W motor oil will work as well if the engine will be started immediately; the assembly lube is a little thicker so probably stays on the bearing/journals longer than motor oil. Lubriplate is also fine for this, especially if the engine won't be started immediately. Lubriplate is also OK for the rocker and valve tips and p-rod tips but use the thick, black moly cam break in lube for the pivot balls (if used).

[edit] Flat tappet cam and lifters

Use a black cam lube w/moly in it on the CLEAN lifter bottoms and cam lobes, including some on the distributor gear and fuel pump eccentric- but not on the bearings or journals. Work the lube in w/pressure (wear gloves- the stuff soaks into/stains the skin), not just laid on top of the surfaces. You want full coverage but not necessary to have it slathered all over the place dripping off, etc. It (the thick moly cam lube) will plug an oil filter if too much is used- but it would take a LOT to do so. Some guys like the red syrup. Soaking the lifters in oil is fine. There is no need to pump them full of oil using a pushrod to stroke them full, but no harm if you do. No moly lube on the body of the lifter- just on the bottoms and the lobes of the cam. Don't neglect to work the lube into the surface of the cam lobes, especially.

[edit] Overhead Cam Engines

Use a black cam lube w/moly in it on the shims, shim buckets and cam lobes - but not on the bearings or journals. Work the lube in w/pressure (wear gloves- the stuff soaks into/stains the skin), not just laid on top of the surfaces. You want full coverage but not necessary to have it slathered all over the place dripping off, etc. It (the thick moly cam lube) will plug an oil filter if too much is used- but it would take a LOT to do so.

[edit] Roller cam and lifters

Roller lifters and roller cam lobes do not need moly break in lube like used on flat tappet cams. Motor oil is sufficient. Nor do roller cam and lifter equipped engines require a 20-30 minute break in at 2000-plus rpm because the cam and lifters do not require breaking in like flat tappet cams and lifters.

[edit] Pistons/rings/cylinders

Use a squirt oil can to lube the rings/ring lands- do not stick the piston down into a can of motor oil, it's just not needed. Wipe the cylinders down w/motor oil as well. No need to float the cylinders in oil- a light coating is all that's needed.

[edit] Preparing the engine to be started

[edit] Prelube (pushrod V8s)

Prelube the engine right before start up. Much is made of getting oil coming from all the pushrods, etc. but as long as the pump is pumping (you will definitely feel the drill labor when the pump is working) and you run the pump long enough to pressurize the system (plumb a temporary gauge to monitor the pressure while priming) and fill the oil filter and galleries, that's good enough- as soon as the engine starts there will be immediate oil pressure, and THAT is what's important- that the engine doesn't run w/o pressure.

It's up to the builder whether to use a manual priming tool or a pressure vessel (below left) to prelube the oil system. Some engines require a pressure vessel because of how the oil pump is driven (some are driven directly off the crank or have a secondary shaft, etc.). Some examples of engines need to be primed using a pressurized primer system are the new MOPAR "Hemi", Ford Mod motors, and Chevy LSx. But most any engine can use a pressure preluber, regardless of the type of oil pump.

When using a manual priming tool on a Chevy engine (example below right) there needs to be a collar at the bottom of the tool (red arrow) that completes the oil pathway that connects the passenger side to the driver side lifter oil gallery. If this collar isn't included, one side of the engine will not be pressurized and air will remain in the passages.

The manual tool is spun in the normal direction of distributor rotation with a drill motor. If unsure, the direction of rotation of most common V8 engines can be looked up here.

Manual Chevy prelube tool

A primer tool can be made from an old distributor by grinding the teeth from the distributor gear along with removing the mechanical advance mechanism.

Homemade Chevy oil system priming tool

[edit] Prelube (OHC Engines with trochoid pumps)

Crank-driven trochoid pumps are very efficient, but they need to be primed, so always fill all the galleries in and around the pump before assembly. Always spin the engine over on the starter before trying to start it (ensure you disable the ignition system before you try this - you don't want the engine to actually run). Do this until you have positive oil pressure. On a car with no pressure gauge, just remove the cam covers while doing this. Once you see oil squirting from the cam caps, then you're done.

[edit] Timing (mechanical distributor)

For installing a Chevy V8 distributor and setting the timing so the engine will fire immediately, see How to install a distributor. Other distributors will install similarly, but be sure of the firing order and distributor rotation, along with any other details that might be different if another make of engine is being worked on.

To help keep the engine from overheating, make sure the engine has plenty of ignition timing advance while it's running to break in the cam. You must not idle the engine even for just a minute, so set the timing using a dial back timing light or make a timing tape so you can see what the timing is at with the engine running at 2000-plus rpm. You can give it 32-34 degrees (not counting the vacuum advance), no problem. It will not hurt to connect the vacuum advance because the engine is running w/o a load, so there won't be detonation from excessive timing unless you were to go WAY up there. But 32 degrees without the vacuum advance hooked up, to as much as 45 degrees with the vacuum advance hooked up is OK. Placing a large fan in front of the radiator can help keep the engine cool as well.

[edit] Timing (electronic)

ECU controlled timing is set by the ignition map - it won't change after break-in. On engines with OHC 4-valve heads you generally have a lot less advance than on 2 valve pushrod designs, so you don't want to use any more than 30 degrees.

[edit] Crate engine break-in instructions

The Chevrolet Performance p/n 12499120 Ram Jet 350ci EFI engine computer has a "break in mode" that controls the rpm for the first three hours of the break in period. From start up to the end of first hour it's limited to no more than 4,000 rpm, second hour is limited to 4500 rpm and the third hour is limited to 5,500 rpm. From that point on there's

Warning Note: The following instructions from the GMPP Circle Track Crate Engine Technical Manual are good guidelines to follow for any rebuilt engine:

Recommended Break-In Procedure Start-up is critical to ensure engine life. This procedure was written with the intent to provide a quick reference and guideline to starting a new or rebuilt engine if a dyno is not available. If you are using a dyno, refer to the dyno operator’s guidelines for start up and initial break in of the engine.

  1. Safety First! Make sure you have proper tools as well as eye protection. If the car is on the ground, be sure the wheels are chocked and the transmission is in neutral.
  2. Be sure to check the oil level in the engine and prime the oil system.
  3. Run the engine between 2,000 and 2,500 rpm, with no-load for first 30 minutes.
  4. Refer to valve lash procedure and lash valves.
  5. Adjust the distributor timing to recommended specifications.
  6. Adjust Carburetor settings. Idle mixture screws, base idle, floats, etc.
  7. After first 30 minutes of the engine running, re-set ignition timing and carb adjustments.
  8. Drive the vehicle at varying speeds and loads for first 30 laps. Be sure not to use a lot of throttle or high rpm’s.
  9. Run 5-6 medium-throttle accelerations to about 4500 rpm and letting off in gear and coasting back down to 2000 rpm.
  10. Run a couple of hard-throttle acceleration to about 5000 rpm then letting off in gear and coasting back down to 2000 rpm.
  11. Change the oil and filter
  12. Drive the next 25 laps without high rpm’s (below 5000 rpm), hard use, or extended periods of high loading.
  13. Change the oil and filter again.
  14. Your engine is now ready for racing.

[edit] Oil

[edit] Break in oil

Use a good quality 30w for break in along with an additive made specially for break in like ZDDPlus. There are also good break in oils available that already contain the right amounts of additives.

30w break in oil
  • Amzoil
  • Brad Penn/Howards Cams
  • Lucas
  • Edelbrock

There are also multigrade break in oils. Royal Purple and Comp Cams' break in oil is 10w-30. Joe Gibbs break in oil is heaver (15w-50), but still a multigrade. I'm sure there are others. Plus there are those who use over the counter multigrade motor oil w/ZDDPlus, etc. added.

At the end of the day it's more important to build the engine right and set it up to fire up immediately after priming the oiling system than to worry too much about the viscosity. But there are not many who will recommend using too thin of a viscosity, like 10w-30/15w-40 for break in.

[edit] Oil after break in

In the US, oil formulations are being changed due to pressure from the EPA. Zinc and phosphorus tend to coat O2 sensors and plug catalytic converters resulting in warranty claims as well as contributing to dirty exhaust emissions, so they are being eliminated from motor oils as we speak. These elements were used in the oil to provide extreme pressure lubrication and protection from galling on heavily loaded engine components such as the cam lobe/lifter crown interface. The oil companies have no choice, they have to follow the guidelines imposed on them.

There are specialty/racing motor oil that will give protection to your new flat tappet cam and lifters. Generally speaking, "over the counter" motor oils are not up to the task; they are constantly changing formulations, so what might have been acceptable for use with a flat tappet valve train might not be the next time you look up the specs, so be very careful when selecting motor oil.

GM has discontinued (and now have re-released) the EOS (Engine Oil Supplement). If you use a molybdenum disulphide-type cam and lifter break in lube applied to the foot of the lifter and cam lobes along with adding the recommended amount of ZDDP additive per quart of good quality oil for initial start up, along with allowing no idle time for the first 20 minutes of run time at 2000 plus rpm while varying engine speed, you've done about as well as you can to prevent lifter/lobe scuff/wear/failure. With subsequent oil changes, the recommended amount of oil supplement should be added at each oil/filter change in order to have along engine life. Or use an oil formulated with sufficient additives, sold by the aftermarket (Joe Gibbs, Royal Purple, etc.).

The loss of those high pressure lubricant supplements from the motor oils that are now available have much less impact on newer engines because of the change to roller cams by the manufacturers. With a roller cam, there is no special procedure for break-in. You just oil the lifters, drop them in and no other special break-in procedures are needed for the cam and lifters. Obviously the rings and other new components will still require a break in period, but with a roller cam the biggest problem associated with breaking in a rebuilt engine (flat tappet cam lobe/lifter failure) is a thing of the past.

[edit] General recommendations

  • Start with a matched and coordinated set of parts. Use the lifters and spring specs recommended by the cam grinder for your particular application and rpm limit. There is no point in using more valve spring pressure than needed, especially in a flat tappet street motor. To do so is asking for problems. Always consult with your favorite cam grinder for cam/lifter/spring recommendations for your particular application. Never rely solely on the recommendation of gearheads on auto forums. It's OK to ask and get general recommendations and suggestions from such sources, but before you lay down your hard-earned money, consult with the manufacturer's tech guy. He will want to know ALL the particulars of your combination including exact static compression ratio, so have all this written down so you can correctly answer questions.
  • You might want to research using special lifters or treatments that help prevent cam lobe/lifter failure. Some options are:
  • Do not break in the cam using the springs that will be eventually run with the cam if the springs are much higher than about 120-130 pounds on the seat at the installed height. Instead, assemble the heads with used stock springs, if they will give enough lift before coil bind. Keep an old set on the shelf just for running in a new motor, then change them out at the 20-30 minute mark. Another option is to remove the inner springs from a dual valve spring for break in. Replace the inner spring afterwards. Manley makes a lever-type tool for this procedure, to be used with compressed air to keep the valve seated. If you don't have a compressor you can feed thin rope/cord down the spark plug hole with the piston down away from TDC. After the rope is fed in, carefully rotate the engine so the piston is compressing the rope up against the valve head. Do this on the compression stroke. Or have a shop do it. Another way is to use a set of reduced-ratio rocker arms for break-in.
  • Checking for interference. Nothing will wipe a cam and lifters quicker than mechanical interference in the valve train. Check for piston to valve clearance, rocker arm to stud clearance at full lift, spring coil bind (stacking solid) and retainer to valve guide boss clearance at full lift. Also check for pushrod to guide clearance to insure the pushrods are not rubbing or binding. You might have one culprit that you didn't catch, such as a bent pushrod. Roll all pushrods on a piece of plate glass before assembly to insure straightness. See: Installing a Racing Camshaft and Valve train points to check.
  • Another problem that can occur if you are not diligent in checking tolerances is tight lifter-to-bore clearance. Failure of the lifters to rotate in the lifter bore will gall the lifter crown/cam lobe in short order, and cam and lifter failure will soon follow. Always oil the lifter bores and lifters when doing mock-up and drop them through the lifter bores. With the lifter bores vertical on the engine stand, the lifters should drop through and fall into your hand with oil on them. If they don't, first inspect the oil gallery holes where they intersect the lifter bores for any raised burrs, etc. Then scrub the lifter bores with a shotgun brass bristle brush and acetone/lacquer thinner to remove all traces of shellac. Just running a rag through the bores is not enough. If the bores are still too tight, hone the lifter bores for additional clearance until they will fall through- only do this if all else fails; too much clearance can reduce oil pressure throughout the engine and is not needed in most cases. The cam grinders are beginning to manufacture their lifters with a shorter radius on the crown to assist in lifter rotation.
  • These suggestions are brought to you by John Callies of Callies Crankshaft:
    • Visually inspect for tool chatter and poor machining.
    • Clean the shaft with mineral spirits and dry thoroughly.
    • Use a hand held propane torch and heat the shaft to disperse any moisture.
    • Spray the cam with graphite. (Another option is to use a dry-film lube made for this)
    • Use quality high pressure lube on cam lobes and lifter crowns (molybdenum disulphide black goop that comes with most cam and lifters).
    • Select a quality lifter since the market is being saturated with offshore lifters that are soft.
    • Make sure on start up the engine is ready to run at 2000-2500 rpm for 20 minutes. ZERO IDLING FOR 20 MINUTES.
  • Make sure the motor is timed and use a known good carb or other induction system as well as ignition system. The new cam and lifters will not tolerate any grinding on the starter to get the motor fired. They are lubed by splash off the crank at higher engine speeds. Have everything ready to go including having the carb primed with fuel and a fully charged battery.
  • Pre-oil the motor with a drill motor and oil pump primer tool such as this one from Jegs. Put a socket on the harmonic damper retaining bolt and rotate the motor through at least 2 full revolutions while priming. There are engines (some MOPAR, Chevy Lx-series, etc.) that will be primed easier by using a pressurized pre-oiler set-up.
  • At the end of the 20 minute break-in period, change the oil and filter. Drive the vehicle for 30 miles, altering the speed and letting the motor rev down from 60 mph to 20 mph with your foot off the gas pedal. Change the oil and filter, using break in oil or added break in oil supplement. If the valve springs were changed, or the inner spring removed for break in, change the valve springs to the correct ones or add the inner spring. Drive for 500 miles and change the oil and filter again. From this point on, use an oil supplement that will provide protection for the flat tappet cam and lifters if that's what is in the engine. This is less than the amount of oil additive that was used at break in.

[edit] Automatic transmission

If just the fluid and filter was changed, 4-5 quarts should fill the tranny to capacity. A freshly rebuilt TH350 will hold about 10 quarts depending on the size of the torque converter. Add a couple more for a TH400.

In the case of a freshly rebuilt or empty transmission, add four quarts to the empty tranny before start up (hopefully ATF was added to the torque converter before installation), then add 3-4 more quarts during the cam break in. Do not try to top it off until the cam has been broken in and the engine can be idled.

[edit] Resources

Crankshaft Coalition articles
Hotrodders forum thread
Personal tools