alright just got the heads back. new 2.02/1.60 valves, ported, shaved .002"
the valves definitely stick out a little and i was just wondering if that is going to create any problems as far as hitting the piston. i was told that i shouldnt have any problems with those valves but i'm still wondering. i'm so anxious to put them on the car, new headers and all, but i dont wanna have to worry about having to pull them right back off. whadya think?

also, is shaving the heads .002" going to make any kind of difference at all?

thanx guys,
Ryan

 

I don't remember the last time I saw a piston to valve issue with a street cam and aftermarket pistons. But you need to check anyways, clay the piston and roll the motor over. The valves sticking below the deck is common on many performance heads and will not cause any problems on its own if PTV clearance is checked unless they are sticking out a bunch and your using a .015" shim gasket.

 

the valves stick out farther because most quality aftermarket valves have a bigger valve face margin, which allows for more resurfaces of the valve face if necessary. usually the seat margin is compensated by the legth of the valve stem on assembly. if they are a good machine shop, they probably took that into mind and set them properly. they probably didn't need any modifying as far as assembly height, but I'm sure they did if it was necessary. I've heard you can run about .600" lift on a stock lt1 bottom end, pistons and heads before you can touch the piston tops... that also depends on your timing advance. if you have a cam with lift of .570 or less, I wouldn't even bother with checking pistons to valve clearances.

 

thanx for the input guys. got everything cleaned up and ready to put them on in the morning

 

The cams lift isn't the biggest factor in valve to piston clearance.....it's the cams overlap......for example, cams down on a 106 or a 108 LSA , will be much closer than cams up on a 112 or a 114LSA......My set-up ended up being really close cause of my cams LSA....a little under what most consider safe......but on previous engine builds, Iv'e ran things even closer without any problems so I wasn't too worried.......with the cam your running im sure it'll be fine but like the others mentioned clay it up so you'll know for sure what clearance you have for both the intakes and the exhaust's......and also importantly so that you'll know what your radial clearance is .........Joe