turboal1

How big a cam can you put in a LS3 without
P2V prob ? can you fit a set 1:8 rockers on a
.556/.586 114LSA cam ?

ColeGTO

iTrader: (3)

Too many variables to say. If you're pushing it that far you should ALWAYS check P to V.

Even a baby 22x cam could have issues if it's installed really early, the heads have been milled significantly, etc.

The MAX lift does not matter with P to V. The valves are closest around 10° BTDC on the exhaust and around 10° ATDC on the intake during the overlap part of the cycle.

There are ways to calculate it without having to purchase a cam and try it out. But, you have to have the short block assembled, heads that are finish machined and valves. Install the heads with the proper head gasket, set the piston to 10° BTDC and measure exhaust valve drop, rotate engine to 10° ATDC and measure intake valve drop. Then call your favorite cam manufacturer and ask them what cams they have that have .xxx" lift at those points (don't forget to subtract the desired P to V clearance you want to run) and discuss your options.


Good luck.

KW Baraka

iTrader: (7)

LOL......you should be more concerned with when the valves open and close than the valve lift.

Check this out.....the cam in my '95 Impala has .668"/.668" lift with my 1.8 rockers.....it would be at .631"/.631" with 1.7 rockers.

But at 229*/242* duration and a 114* LSA, P/V clearance is nowhere close to being an issue for me.

Push us the full specs of the cam and the heads you'll be using.....then we can give you a good answer to your question.

KW

dreadpirateroberts

iTrader: (1)

Always be ready to flycut with an aftermarket cam.

there is also an excel spreadsheet PTV calculator floating around. I have a copy, but it won't run on open office calc.