cam degreeing

[bad440]

was talking with a race engine builder about cams, he said he degrees them in so they pull the most vacume.he's not the most talkative guy so i left it at that.so would you advance it or retard the cam for most vacume?and why?

 

[Rodzilla]

Never heard of that but I'm no expert. Generally you degree a cam in so you get or double check that it's install as per the cam card. Sometimes they arent ground spot on And for the experts out there who may want it degreed or retarded from what it should be set at for what ever reason.

 

[rnaz]

You would advance it, IIRC. It starts opening the intake valve sooner on the intake stroke, which does a couple of things.

It will get more air/fuel in the cylinder, and effectively lower the RPM of the start of the power band, which also gives less piston to valve clearance, so you have to be careful.

Conversely, retarding the cam will raise the power band, and give more piston to valve clearance.

 

[bad440]

so advancing the cam helps in raising the compression ratio ?????

 

[rnaz]

No. It raises the cylinder pressure slightly from more volume. The static compression ratio remains the same because you haven't changed the bore or stroke.

 

[bad440]

sorry thats what i meant cyl. pressure