If you read anything about cam break in, the first thing they say is, get the rpm up to 1800-2000 as soon as the engine fires, no messing around with tune up or adjustment, ASAP. You must have everything as close as possible before you start.
If the engine fires up, get the rpm up, don't mess with the timing, its close enough if its running. Read up at the Comp Cams site or any of the other cam makers sites on break-in procedures, its not like it used to be 20 years ago! After the 15 to 20 minutes of break-in, then set your timing and carb settings. Also, don't start out with a new or untried carburetor, it just adds more worries and unknowns.
The first few rpm's are the most critical, once up to speed, the crank throughs enough oil to lube the cam/lifter contact point. Before that, its the cam lube you have installed, and by now, thats been wiped off and is laying in the oil pan. Pull the intake and look, the cam will not be dry, but it won't be greased either. There is no oil system that lubes the cam/lifter contact point, is all splash from the crank and rods. High rpm is the only way to supply enough for break-in. Cam lube is only good for the first few rotations and the heavier the valve spring, the fewer rotations it stays on the lobe.
And, yes, just a few turns of the crank before break in can indeed hurt the camshaft if every surface is not 100% correct. Did you knock the edge off each lobe and check each lifter for a crown on the face? Was the oil system primed? does it have oil pressure? Do you have break-in oil or additives in the oil?
Pre-run in is not the time to be checking compression. That should have been figured out on paper before this point. And afterwards only if it doesn't run right.
I have started a lot of expensive engines over the last few years with out any problems, one thing I always do is start them with in 24 hours of installing the cam, and only turning them over 2 revolutions to set the valve train, any more then that just wipes the cam grease off. I install the intake after adjusting the valve train so I can add more grease or break in lube back on the cam lobes. Also waiting days or weeks to start lets the cam grease drip off.
As far as compression at cranking and how much it should have all depends on the camshaft timing, how it was ground, not so much as how it was installed. The cam card will tell you how much overlap it has. You can also figure it out with a degree wheel and dial indicator. As for timing marks aligning, the gears are 2-1, they will be right every other rotation but will still be in alignment using a straight edge each rotation. Once at TDC valves closed, once at TDC valves open.
You also have to consider the compression test invalid if the lifters were not full of oil. You will not get full valve lift with a empty lifter.
Joe
Last edited by Joe H; 12/30/2011 4:35 AM.
