what size gasket should i use for a .25mm bore i cant seem to find one at 81.25mm help please? (have ctr .25 oversized pistons)

 

oem should be fine. the oem gasket uses a tad bit of clearance on the inside diameter of the cylinder walls and .25 isnt all that much.

i used an oem gasket on my oversized pistons.

 

Or you can try this.

http://www.c-speedracing.com/howto/c...c/compcalc.php

 

what does a compression calculator have anything to do with his question?

 

you need 81.50mm.

 

yeah i was told oem was fine by my shop teacher today. its my first build im learning its a lot more harder than i originaly thought

 

well first off its .02" or .025" over which will make it 81.5mm bore. not 81.25 bore. therefor you need a 81.5mm gasket. if you had a smaller gasket think about what that will do to the flow...not good.

 

.02 is pretty standard for an overbore. an OEM should be fine.

 

thanks guys apreciate the advice.

 

since ctr pistons only come from japan and are only used in civic type r motors, would'nt you think that they would use the metric system? hence, a .25mm oversized piston would still be .25mm over, not converted to hundredths of an inch like the standard system.

 

As already stated, the OEM head gasket is fine; there is enough clearance for a 0.25mm overbore.

 

well shieettttt i was assuming cause most of the time .020 over is usually in inches not mm. so ya i guess stock bore hg will work just fine.

 

i put mm in my first post why would you think its standard

 

i thought you were saying something else. duh.