Camshaft Degreeing Instructions

moper said
lil, Comp grinds thier cams with advance in it. That's whay it's in at 106, yet the camshaft centerline listed is 110. Just my opinion of course.. One can advance the installed centerline, but advancing a cam that is properly chosen, and designed as the XE line is for making cylinder pressure, can put you over the pump gas threshold pretty easy. Also, if he's running a tensioner and/or a good chain, the stretch means virually nothing. It's there of course, but it will not make any difference. 2° is barely measurable/feelable, 6° is huge.

Moper,

Yes, I understand that Comp grinds their cams with advance in them. I'm not a noob. I built engines for 10 years professionally. The issue is that you don't know if the crank keyway is machined in exactly the right place in relation to the rod throws. There could also be small errors in the machining of the timing set, the block, etc. If you get a few of these errors in the same engine, it's called stacked tolerances.

The goal is to get the cam installed exactly at the recommended centerline. Typically, Comp recommends that their cams should be installed at a 106 centerline, even though the centerline of the intake lobe (aka point of maximum lift) is at 110 degrees ATDC. That's your ground-in advance.

What I'm saying is that if the cam is at 107 from the day it's assembled, it's starting out 1 degree retarded from where it should be. Tensioner or no tensioner, the chain will stretch some. I've seen both Cloyes and Rollmaster chains stretched quite a bit after only a little time in an engine. What happens when it stretches? The cam retards! So if it's at 107 with a straight key after checking and re-checking several times, I would use whatever key is needed to get it to at least 106. If it gets a little more advanced than that, no big deal. In no time it will be right where it should be. Long term, it will keep the motor running better for longer. Even the best chains stretch!