ring gap

vibrac

Well Known and Active Forum User
VOC Member
10 thou per inch is my line in the sand so thats about 33 thou for a standard barrel I cant file to a thou so between 32-38 is where it generally ends up
 

chankly bore

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Non-VOC Member
I wuz always told .004" to .005" per inch of bore diameter on compression rings and a bit more on the oil control ring, but maybe I'm out of date as usual. Works for me, though! P.E.I. says .005" per inch if engines are warmed up and .010" if they are subject to stress from cold. Interestingly Richardson gives .010" to.020" total gap on the oil ring, but I don't remember what type of oil ring the Omega pistons use. Whatever else you do, ensure that the bore is round, the muff fit is right, the con-rod is central, the bore is square to the crankcase mouth, the oil feed is proved to the rear of the piston below the scraper at B.D.C. and the muff is a snug fit cold into the crankcase mouth.
 

vibrac

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VOC Member
Yes I should have said my racers are ten thou but at the moment 3 of my engines including 1 road bike were built as racing engines
I cant say I see much smoke or high oil consumption but then I use Castrol R.....
 

sixpack

Forum User
Non-VOC Member
10 thou per inch is my line in the sand so thats about 33 thou for a standard barrel I cant file to a thou so between 32-38 is where it generally ends up

many thanks--sounds like alot---we are talking about aftermarket Omega LE correct ????
 

vibrac

Well Known and Active Forum User
VOC Member
Thats irrespective of piston
this century I have used kempaloid and the VOCSC item I believe they are are low expansion die cast I certainly had the bores done with closer tolerances to the piston than in Richardson and I think that is where the low ex needs to be considered, the ring gap just follows
 

Big Sid

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Non-VOC Member
On ring end gaps , original bore diameter , factory OS range . 16 to 19 thou . Is fine . A thou or so more is of no consequence . Too close is where a problem can arise . The ends might butt together and cause breakage . Sid .
 
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