Top End Rebuild Help

[Jet5Kier4Life]

Hey Guys and Gals,

I did a search, but didn't come up with anything.

So, I have an '06 Superjet with a built engine.
It has a 61X Cyl that has been bored to about 83mm. I talked to my engine guy and he said that it can be cleanly bored to 83.5mm.
So my question is: is it safe to bore a 61X sleeve to 83.5mm or 84mm?
I have heard that the bottom of the sleeve and break off if you overbore the cyl too much. I read on Group K's website that you need to resleeve at 84mm.

ohh and the cyl is ported too

piston options
ProX makes up to 83mm (no go)
Wiseco makes a to 84mm (could do it)
Pro-Tec makes a 83.5mm (will it break my sleeve?)


so do you think I should go to the 83.5mm or 84mm and preserve the porting or spend the extra $$ to resleeve it and match the porting

thanks for the help

[#ZERO]

You can safely bore that 61X cylinder to 84mm and I don't believe Pro-Tec sells those 83.5mm pistons anymore.

[Matt_E]

GroupK offers 84mm 61X cylinders, so he must have some confidence it'll last.
I believe he states you can overbore twice, to 84.5

I've never seen 83.5mm pistons, and I've looked a couple times. But I haven't been in this for all that long, so I may very well have missed it.

[Jet5Kier4Life]

thanks guys, I'll make some phone calls today and see if they still make those pistons

do you think its worth the extra $$ to go with the Wisecos over the ProTecs? they are over twice the price!

[Jump On It]

pm SUPERJET-113 on here and see what he can get for ya...great seller/prices...save $ on quality gaskets too...