bore size? piston size?

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Senior Member
what size pistons would i need for a 81.5mm bored block? dumb question i know, but the answer im lookin for is not 81.5.......found some on ebay for example said .020 over and 3.209 bore size.??? im dumb


81.5 = mm.

0.030 = inches.

do some sae to metric conversion.

and frankly, if you're looking at pistons for a honda sold in us measurements, i'd pass on thenm, cuz they are probably garbage or sold buy some tard cart TRYING to get in the import market and doesn't have a clue.


Senior Member
81.5 millimeter = 3.2086614 inch....basically a 3.209...and its a dart block...


just be careful with that block...

Originally posted by earl
Darts are a high quality block but you will spend a lot more than you think. They must be bored, honed and I feel surfaced before using. If a shop does not know how to bore this block properly, the sleeves will raise up during the bore. Then it gets surfaced back to flat. When you start the motor, the sleeves will drop back down to their original spot and will cause the head gasket to blow. One solution is to bore with a deck plate on. There is more to this block than meets the eye, so all I am saying is just be careful if you choose the Dart.


Mad scientist
Originally posted by arroshiz@May 26 2005, 02:03 PM
comes, surfaced honed and bored...i think it should be alright
[post=503997]Quoted post[/post]​

Unless it comes with a set of pistons numbered 1 2 3 4 and the bores match the pistons, it wasn't bored/honed correctly. You'll have to do it again.