ring gap

Top End (cylinders pushrods etc.)
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65eglide
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ring gap

#1

Post by 65eglide »

after pulling the heads and cylinders, found out pistons were .030
just got them back from the shop, so I trying to figure out what the new ring gap should be
they call for a .010-.020 on the std pistons, so should the new gap be .013-.023 ?
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Re: ring gap

#2

Post by George Greer »

.010 to .020" End gap.

The Oversize of the piston don't matter, the manuals states end gap size ... Period.

Set it at that and your done.

George
65eglide
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Re: ring gap

#3

Post by 65eglide »

just in a couple I've measured I got a gap of .020
don't really like being on the high end

just increases the chance of leakage, and degrading performance somewhat

I still have to measure the bores of both cylinders to make sure there exact,
a difference of .001 will change the gap ( .001 x 3.1416)
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Re: ring gap

#4

Post by nmaineron »

65,your over thinking this...just take your rings and dedicate them to a piston and a bore and fit them.I like to go an inch from the top squarely in the bore to get my gap measurement and adjust if needed...
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Re: ring gap

#5

Post by Hauula Pan »

If the bore job was done correctly & your cylinders are .030 over then your .030 over rings should fit within specs. However if you simply don't like them being at the high end & want a smaller gap you can get a set one size larger & cut them down.
65eglide
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Re: ring gap

#6

Post by 65eglide »

both cylinders turned out to be exact, so after re-measuring turns out it's about 18, which is fine.

on these motors probably does not make much of a difference hp wise
just use to 700hp beasts where that does matter
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Re: ring gap

#7

Post by Hauula Pan »

For the most part these old motors are extremely forgiving as far as wear & tolerances are concerned. I'm sure you've already noticed that even most of the original factory specs. are pretty loose compared to today's motors. Good luck & hope you get her back up & running soon.
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Re: ring gap

#8

Post by 65eglide »

ya, did notice that
since when looking for some torque specs their answer is to tighten then two whacks with a mallet
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Re: ring gap

#9

Post by Cotten »

65eglide wrote:ya, did notice that
since when looking for some torque specs their answer is to tighten then two whacks with a mallet
65eglide!

You may be able to get away with that at your low overbore, but by .060" there is definite danger of pinching the skirts against the cylinder spigots from fastener stress.

A cheap torsion torque-wrench is accurate and effective:
Slowly up to 65ft-lbs on the headbolts, and no more than 40ft-lbs on the cylinder base nuts. Properly, any bores .050" and over benefit from stressing upon plates while fitting for the pistons, and by .070" it is mandatory, all the way to .100 oversize.

....Cotten
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