end gap

[smilinicon]

Eric Gorr and other engine builders,

I was wondering how you handle a situation where a new piston ring exeeds the allowable end gap tolerance. I remember in the past that it was acceptable to use an oversize ring and file it to spec, yet I have also been told that rings are made with round stock and using an oversize ring (filed to spec) would cause problems. Bore is within limits.

Thanks in advance.

 

[EricGorr]

If the rings for that bore size have excessive gap, then the bore is probably worn. Some of the specs listed in the factory service manuals may also be erroneous. Normally I look for .015-.025 inches up to 60mm bores and .020-.030 inches on bigger bores.

 

[Pete Payne]

If it is a nicasil bore--- replate it. If it is a sleeved bore -- overbore it for the next up piston. This gives you a good excuse to modify it for more H.P.

 

[smilinicon]

Thank you for the answers! Yes, it is a Nicasil bore and it is brand new - only test-run at the factory. The bore measures correctly. I believe it is in the ring tolerance. I like your answer about the bogus information in the manuals... I am finding other inconsistancies here and there. My ring is well within your tolerances you stated.

Pete: no excuse needed! :) I do love building MX engines... first time I have done it in twenty years.