Cam Timing Assumption

[ZOA NOM]

Let's say, for example, someone I know put their 1-3 P&C's on upside-down, and discovered the error after actually running the motor for a few laps. So he pulled the motor and decided to leave the 4-6 side alone while pulling the 1-3's and reinstalling them the correct way. This required removal of the cam tower and chain box on that side, so the cam timing is lost. If he lines up Z1 with the centerline of the case, and the 4-6 side cam (930 stamp) is pointed up, is it certain that cylinder #1 is at TDC? If so, I (I mean he) could turn the left cam until the 930 stamp pointed up, and he would be pretty close to a properly timed left side cam. This would all be confirmed with the dial indicator, but he is concerned that he is missing something. Doesn't the right side cam point straight up once for every 720 degrees of crankshaft rotation? He would like to avoid messing with the right side cam timing if it isn't necessary.

[efhughes3]

As a newly minted "pro" at cam timing (hahaha), I think you'd (your friend) be OK. You'd double check by making sure that the LH side (#1) is going into overlap when Z1 is 360 degrees from when RH (#4) goes into overlap. That is to say when at Z1, either #1 OR #4 is starting to open the intake. They can't both do it at the same time.

[ZOA NOM]

That's what I... er... HE figured. Thanks.

One other question; is there anything to be gained by setting the timing to either extreme of the .0043"-.0055" range?

[Eagledriver]

Rick,

Good to see you are on your way to getting your engine done. I've tried the retarded end of the cam timing on a street/DE Carrera. I was looking for max HP. It felt less fast except at 6000 RPM and higher. The common wisdom to improve 3.2 and SC performace is to advance the cam. I would set it toward the .055 end. You may lose a couple of HP at 6200 RPM but you'll gain more than a couple at 5000 RPM. Overall with our gearing I think the advanced setting will be better.

-Andy

[ZOA NOM]

Thanks Andy, I'll tell "him".