Thread: finished deck heights?

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I know that making and engine run stronger can be dome by improving the quench. My question is there a formula for correct piston to deck heights on a small block chevy. My pistons are .005" below th deck and I can add different gaskets for clearence, but is there a set formula for this? How do you determine the percise piston pin height?

In my experience, it doesn't make much difference how you get there, as long as you get to around 0.035" to 0.040" with a tight fitting piston on a small block. On a larger bore motor where the piston may have a little more room to rock on the pin or on a motor with forged pistons where the piston to bore clearance is a little bigger, I might go a little more, 0.040" to 0.045". You can use a 0.016" gasket with the pistons down in the bore 0.019" to 0.024" for instance or you could use a 0.051" gasket with the pistons popped out of the deck by 0.011" to 0.016". With pistons down in the bore by 0.005" on a small block, I'd be using a 0.040" or 0.039" gasket with cast or hyper pistons.

I'm not sure about your other question. If you're trying to determine the compression height of the piston, use your 6" caliper to measure from the top of the pin bore to the crown of the piston, then measure the pin. Add half the pin diameter to the measurement from the top of the pin bore to the crown.

head gaskets come in dif thickness look in fel-pro book i would not cut any more off the deck i check piston pin heigth by diving the piston pin in 1/2 add half to the side measurement from top of the deck of the piston to top of the pin and add the half of the piston pin this will get you very close if are use pistons with no numbers on the pistons IF SO LOOK UP THE NUMERS and if you add half the stroke of the crank and the rod and your piston ch will tell you how much you need to deck to but should be mock up so you know all your parts are the right size if any or all parts are off just a small amount you get stack up and and can be up or down on size on deck height ...TECHINSPECTOR 1 IS FASTER THAN ME

Not trying to steal your thread, 37, just another question on deck height and squish..... On the 6" rod 383 Chevy strokers, is squish set the same, different, or doesn't the long rod/long burn concept have anything to do with squish???? Be nice, I'm a chassis guy, not an engine guy!!!!!

I've always set the squish the same, regardless of the rod/stroke ratio. I've never experimented with altering the squish based on rod length, but I would guess that you'd never see any difference on the dyno.

Thanks Tech. I didn't think it would matter, but thought I would ask the experts.

Tech,Pat, Thanks for the info. I was going to go with a .035 gasket but I guess I should go with the .040 thickness. By the way they are Hyper pistons. Tech that's exactly what I wanted to do in measuring the compression hight of the piston. Now I know because I have two experts tell me. Thanks again.

Originally Posted by chevy 37

Tech,Pat, Thanks for the info. I was going to go with a .035 gasket but I guess I should go with the .040 thickness. By the way they are Hyper pistons. Tech that's exactly what I wanted to do in measuring the compression hight of the piston. Now I know because I have two experts tell me. Thanks again.

Use the 0.035" gasket.