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Old 07-21-2008, 08:40 AM   #13
crainholio
 
Join Date: Nov 2004
Location: Randolph
Posts: 198
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Quote:
Originally Posted by Blacdout96 View Post
should I purchase a micrometer as well to read to diamter of the pistons n such? im suprised that they wouldnt all be the same size, being cut form a machine or formed in a mold.
You need that measurement as well as each bore's inside diameter so you can properly set the clearance. You can't adjust the piston size, but you can hone the bore to get the clearance right. Run it too tight, and it will seize at temp.

Just measure and record all 8 pistons, then measure and record all 8 bores. Match them up to get the out-of-the-box clearances as close as possible, use a Sharpie to write the bore # on the crown of each piston so they don't get mixed up.

Bring your measurements and the block back to the machine shop, as well as your desired bore clearance spec, and they'll hone the bores to the size you need.

MAKE SURE the shop uses torque plates during final honing. This is important to ensuring good ring seal.

(the really fancy shops can heat the block to operating temp so the honing is done as closely as possible to actual operating conditions)
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1982 Z28 w/ '01 LS1 + T56, TR224 cam, Katech oil pump, JWIS chain
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