Ninety5five0

Anyone know what my max lift should be before i start to have valve/piston clearance issues ?

Or what i should keep it below to play it safe.

Joel5.0

Total valve lift is not directly related to PtV issues....when the valves are at total lift, the piston is way down in the cylinder....it's the overlap period (exh/intake valves are slightly opened at the same time when the piston is reaching exhaust TDC) that is required to be checked.....



Suggest to check http://www.fordmuscle.com/fundamentals/pistontovalve/

aode08

with stock 1.6 roller rockers and valves no larger than 1.94 intake, 1.6 exhaust your good up to .550 lift, .224 -.230 duration, after those number CHECK.
Machinist/Race Car Builder gave me this info

1.7's add .027 lift to any cam , in fact the cobra has 1.7 roller lifters

Nadelle

ive heard .500 is safe, i wouldnt go higher than that if it was my engine.

94gtcoupe

a ford racing f cam has .552 on both exhaust and intake valves and i never heard of any one having issues with this

LCBlackDep183

Okay piggybacking, how do you calculate your lift/duration depending on your cam and lifters?

aode08

dont go over .500 though, you dont want too big of cam = no advantage

FullAuto

The 1.7s do not add .027 to any cam. It's a percentage. It adds different amount to every different cam.

You really should check with all cam installations, but I'd definately be worried about anything OTS that is more than .540 @ 224*. I think you'll have problems with more duration than that on most OTS cams.

FullAuto

F cam is .512, not .552.

hellas85stang

check it with play do...and measure....and just cuz a cams bigger dont mean ya car will go faster...alot more variables..