02RedHawk

iTrader: (17)

Let's say a cam has the following specs:
Cam "A": 224/224 XE-R Lobe, 112LSA +4 Deg Advance on 108 ICL.

Using Cam "A" and a set of .030" milled LS6 heads (2.02/1.57 valves), it yields a piston-to-valve clearance of .060".

Now, how will the PtV clearance change - that is, how much more PtV clearance will there be - with Cam "B" (below) and using the same .030" milled LS6 heads (2.02/1.57 valves)?

Cam "B": 224/224 XE-R Lobe, 114LSA +2 Deg Advance on 112 ICL.

Any additional information needed to better answer this question more accurately?


TIA........

1fastWS6

iTrader: (3)

If you have .060" now with the INTAKE valve on a 108 icl, then retarding it to a 112 icl should increase the clearance on the intake and decrease it on the exhaust. How much? Couldn't tell you for sure, but 4* difference is probably only .020" or so. Call Comp and see if they can give you an idea.

Beast96Z

iTrader: (21)

He's asking how much he'll gain if he goes from 112+4 to a 114+2. In a basic test that I did while assembaling my motor, 1 degree of advance changed the clearence about .007". So you'll gain about .014" just by taking away 2 degrees of advance. I don't know how much the LSA will change it, but you will gain more clearence with the 114.

02RedHawk

iTrader: (17)

So far, this is good news!

1fastWS6

iTrader: (3)

112+4, 108* intake centerline, 220* exhaust centerline
114+2, 112* intake centerline, 226* exhaust centerline

You're losing 4* on the intake side going from a 108icl to a 112 icl, so if you -theoretically- gained .007" per degree then you'll gain .028". That .007" sounds fairly close to what I saw when I degreed my cam in, but keep in mind EVERY lobe will be different somewhat for that value.

On the exhaust side, you'll be 6* retarded with the 114+2 vs the 112+4 so that -should- give you more clearance on the exhaust also.

Hope that helps.