which pistons would work best?

[nawlins-tim]

Did you degree the cam straight up. did you use a degree wheel or did you possibly get the alignment of your timing chain components in an undesireable location? But you may or may not notice yhat in motor performance. I have an Isky cam with .510 lift, and a 58 cc head ,with pistons only with the reliefs.With no clearance issues. are you useing 1.6 rocker arms? Do a clay test and see if a thicker head gasket would fix your problem.

 

[adumb]

okay, stock length pushrods, 1.6 ratio rockers, heads have never been decked.

i did not degree my cam, i suppose the grind could be off,

if i were to go thicker head gasket how thick is a regular felpro to start with? i almost remember .017 when i was looking it up before, is that correct?

 

[86Cutlass383SR]

A .017" gasket is a shim type gasket. A composition gasket would be in the .025" - .050" range.

Before I rebuilt my 383 I was running a flat top piston with 64cc heads and a .495"//502" hyd roller cam which I didn't degree in. I was using a .041" Felpro gasket and never had a bit of piston valve clearance problem.

Since you had the heads off, put a small dab of clay on the piston and bolt the head down. No gasket and just snug it up. Borrow or buy a solid lifter to use instead of the hyd lifter. The hyd lifter won't give a true reading since it needs oil press to keep it pumped up. Slowly rotate engine by hand. Remove head and measure your clay and that will tell you what the p-v clearance is. I can't remember off the top of my head what the clearance should be.

 

[adumb]

thanks for the input guys,

im gonna order in a new rotating assembly and i will def be doing some clay tests

 

[DRIVEN]

Why are you buying a new rotating assembly? If you reassemble your current top-end combination while only changing crank/pistons you will almost definitely have the same results. You could just put standard composition head gaskets back in and the problem would be solved. Another question: Why the 1.6 rockers? Any ratio over 1.5 is to "trick" the engine into thinking the cam is bigger (when using the stock cam) or for fine tuning after a cam swap. It also adds more stress to the valve-train. If you were installing in a new cam why didn't you just choose the grind you wanted in the first place? You will find that by stepping back to a 1.5 or 1.55 ratio you will pick up both the clearance you need and some low-end torque. Just something to consider before turning a small problem that is both cheap and easy to fix into an expensive and complicated one. Good luck and tell us how it turns out.

 

[adumb]

the 1.6 rockers came with the iron eagle heads. the guy threw in the comp cams roller tip rockers for free so i took them, i suppose at this point i would be willing to trade down to a 1.5 comp cam roller tip rocker but with the slight amount i was hitting i may try the thicker head gasket,

i wasnt running a .017 head gasket btw, i was just using a run of the mill felpro head gasket,