Editing How to prep and start a rebuilt engine (section)
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==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: **Hard-faced lifters with a stellite face on the lifter crown that will resist scuffing. **Comp Cams has an optional [http://www.compcams.com/nitriding/ nitriding process] that can be applied to any of their cams for around $100 over the cost of the cam. **[http://www.4secondsflat.com/Composite%20lifters.htm SM composite lifters], ~$700/set. **[http://www.4secondsflat.com/SM%20Tool%20Steel%20Lifters.htm SM tool steel lifters], ~$485-$625/set. *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: [http://www.iskycams.com/camshaft.php 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 [http://www.jegs.com/i/JEGS-Performance-Products/555/23640/10002/-1?parentProductId=754806 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.
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