Checking deck height
 

I am getting conflicting opinions. When checking deck height, would you check it in the center (over the wrist pin) or at the top and the bottom of the cylinder and rock the piston to get a minimum? How does NHRA check it in tear down? I am checking a small block Chevy dish engine.
Thanks,
Joe

Re: Checking deck height
 

On our Olds, they've always placed the piston at TDC and then checked at the 12, 3, 6, and 9 o'clock positons and averaged it. So that's how I do it. That's the only way to account for rockover.

Jerry

Re: Checking deck height
 

Joe I've set 5 IHRA records and ever time they have me rock it back and forth to get it on top...they then set the bridge on zero @ the deck then put it on the center of the pistion to check hight.

Re: Checking deck height
 

That won't work with a dish piston, although it would give us dish piston guys a big bump in compression the head gasket would be really fat.

Re: Checking deck height
 

Thanks Bud. Greg. He originally asked about a DISHED piston. I responded as I did because our 307 Olds runs a dished piston that has been checked as I described. Flat top pistons could be checked either way I guess.

Jerry

Re: Checking deck height
 

Sorry guys I missed the dish deal.....guess it could be a pain to check a dish! ;)

Re: Checking deck height
 

Just messin with you Greg. I know you knew better.
I naven't been torn down, but we checked mine at the 12, 3, 6, 9 and allowed some for a cleanup later. If you set it up now with a thin gasket, after a clean up you can go to a thicker gasket to make up for the cut.

This does bring up another question. Whats more important, duration / lift, or compression ?
Keep in mind, my car is a pure stocker with a legal cam.

Re: Checking deck height
 

Hey Guys,
Thanks for the responses! I get what Greg means. With a dish, we just have to stay on the wrist pin center line but move forward or rearward to catch the high spot on the piston. Jerry's way seems the best and the measurement comes out the same both ways.
Thanks again for the help,
Joe