I have comps #3100 double roller set, it comes with different bushings to dial in the cam.

If I the cam is installed; #1 TDC, cam gear with the "0" at 6:00, crank gear "0" at 12:00, and the black (no offset bushing) in the cam gear.

Is this correct. Is this how comp intended the cam to be installed?

Doesn't comp advance their grind by 4 degrees. What effect does advancing or retartding have on the power band.

Thanks, Steve.

 

I never installed any bushings with the cam. I used a Cloyes double roller chain, lined the dots up and bolted them on and never had any problems.

I beleive Comp wants them degreed at a 106 centerline. But that takes the degree wheel and a few other things.

Strait up is usually good enough for most people. Advancing and retarding the cam itself instead of the distributor only seems like it would lead to timing probles when you first start the motor. I've always done it just strait up..


-Aaron

 

That is how Comp intended it to be. Cam manufactures will grind different amounts of advance into certain grind cams as they feel is needed. Advancing or retarding a cam is a method of tuning the cam to a particular engine conbination. If you choose the exact perfect cam for your combination then there is no need to advance or retard it. This is very hard to do without a past experience with your combination. With an engine dyno we will advance or retard a cam to find what the engine "likes".

You may want to post all you specs and have someone DD2000 it and see what advancing or retarding the cam does with your combo. Closest thing you can do short of having the motor dynoed.


When you advance a cam it will move the torque curve down the RPM band and will flatten the torque curve out. When you retard a cam it will move the torque curve up the RPM band, make more HP but in a small RPM range, making the motor peakier. This is a VERY general statement and by no means appies to all motors. Some motors will make more power with the cam advanced , others will make more power with the cam retarded. It all depends on if you choose the optimum cam to start with.


Changing cam timing does not change the procedure for ignition timing. You still set your ignition timing the same way as always.


[Modified by Pete79L82, 6:50 AM 4/25/2003]

 

ttt

 

Here is a desktop dyno of your combination. As you can see installing the cam with a 0° cam bushing will create more torque and a little less horsepower over 5000 RPM as opposed to using a 4° bushing to retard the cam. Anytime I advanced the cam more than what is ground into it the horsepower dropped off very quickly.

PS: I didn't know what compression you are using so I set it at 9.0-1



Pete


[Modified by Pete79L82, 6:28 PM 4/25/2003]


[Modified by Pete79L82, 6:29 PM 4/25/2003]

 

Wow, that DDD looks cool Pete. Thanks.

Well after dinner tonight, I removed the offset bushing and put the no offset one in. Seeing the DDD numbers makes me feel much better about it.

I think (hope) my compression will be around 9.5:1 I didn't have the block decked, I wanted to keep my numbers :)

Thanks to all who helped, Steve.


[Modified by snb73, 12:03 AM 4/26/2003]