Cylinder

[Tony]

I talked to a few builders when I was looking at big bores last year. Chuckie at Team Scream said he wouldn't bore a 61x cylinder to 84mm. Paul Lehr said the same thing. CG racing said they wouldn't do it either. Jetworks wouldn't do it. Harry Klemm at Groupk said it was okay to do on a 'recreational' motor. I ended up getting a resleeved big bore.:shrug:

So, what you are saying is to re-sleeve ....

 

[accbr]

So, what you are saying is to re-sleeve ....

That seemed to be the consensus from all these builders when I talked to them. Your cylinders look like they've been ported, so the new sleeves would have to be port matched. The bottoms of your sleeves have definitely been cut.

I know some people will say to bore it to 84.5 or 85. You just have to decide if it's worth the risk. It could take out a few other expensive parts if it lets go.

 

[Matt_E]

I've done it on a couple topends I didn't care about.
I wouldn't do it on a better motor.

 

[Cross]

I ran a 61x at 84.5 for multiple seasons with no issues. It was a ported cylinder, cases, total loss, dry pipe, 200 lbs compression, etc. The sleeves do get pretty thin, but can still be run reliably.
I figure a lot of builders error on the side of caution when it comes to recommending boring out a stock cylinder over 84mm.

 

[cosander]

84.5 will work 85 will snag. so says the neighbor

 

[waxhead]

I have run them at 84 plenty of times and on race engines as well
if you go to a bigger sleeve you cut into the transfer port volume