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piston running clearance

stove

Active member
Joined
Dec 13, 2002
I am having my pistons hone-fitted tommorow.
Where do you recomend the running clearance be at,the tight or loose end of the 0.0004"-0.0016" range specs.

P.S. the engine is a b23ft and the pistons are standard "E" bore (96.245mm.)

Thanks!

Steve
 
I would suggest that you have the bores honed to final piston-cyl clearance of 0.0010-0.0012 inches; hopefully with a flex-hone to give a plateau finish.

Those 23FT pistons are "tall" compared to the 230FTs, so you won't have to worry about piston slap for a lot of miles. Those 23FT pistons are also forged; that is why I suggest final hone to the mid/mid-high end of recommended clearance. If those pistons were cast, I would suggest going on the tighter side (0.0006-0.0009 inches)....

.....these suggestions are for a street use engine; some might suggest more clearance for a competition use; a subject of much debate.....

the right wall surface is just as important as the clearance--some might say more important than--...a plateau finish is the desired surface.....a google search for that term will result in information with illustrations describing the advantages of a plateau surface....definitely worth the effort to both read up on it, and to do it....

then there is the debatable subject of what grit flex-hone to use....compare what grit the piston ring mfr recommends; discuss it with your machinist.....if you are using mahle pistons/rings, I am almost certain that the comp rings are chromed; that is subject to verification...whether the comp rings are chromed or moly faced affects what grit hone to use....
 
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