How to check piston to deck clearance
The subject is a Toyota 2ZZ
The block is being milled to ensure a good gasket sealing surface.
The short block must be dry assembled with crank, rods, and pistons.
Rod and main bearings are installed, and only the 2nd ring installed.
The tools used are a dial indicator and bridge stand
Now zero the dial indicator on the block with .100 preload.
(http://i261.photobucket.com/albums/ii49/BogusSVO/How%20to/how%20to%202/DSCF4412.jpg)
Next slide the dial indicator over the piston and rock the crank back and forth till the highest reading is found.
(http://i261.photobucket.com/albums/ii49/BogusSVO/How%20to/how%20to%202/DSCF4413.jpg)
Now read the difference from zero to the depth of the piston.
In this case it was .004
It took .003 to square the block. Leaving the piston .001 in the bore at true TDC
I believe most our ford 302 are piston above deck clearance, I know mine was when I pulled it apart. think .006 above deck
stock 302 engines are about .015 in the hole
you should have some good compression. Has your block been decked?
funny a least I think I was the first in there. I brought some digital pics to my machine shop and he said the same thing there know such thing, but I don’t know where I herd it here or coral that it was common the our motor came like that. Both father and son in the shop said I probably will be real happy with the compression of my motor.
.007 not.006 now that im going to the pics. if you look good you can see the piston sticking out a bit.
(http://i266.photobucket.com/albums/ii266/BillyInnes/DSC01004.jpg)
i know iit should be measured from the middle if i recall i think i did it like this for picture reasons.
(http://i266.photobucket.com/albums/ii266/BillyInnes/0b815d45.jpg)
with that dish piston, you measured right.... if you would have measured in the middle of the piston you would have the depth of the dish in there too.....
OK yesterday it just didn’t look right now i remember like you said i was instructed to do it like that.. Matter a fact those tools I borrowed from my machine shop when I bothered him to much about the piston sticking out. He didn’t believe me so he gave me the tool to measure. he instructed me how to use it on a chevy he was working on and I took pic to show him.
whats the casting number on your block?