Ring Gap Question

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thomasfouraker

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Purchased some Moly Coated Steel rings from Hastings for a .030 over 408 stroker build on a Magnum.

Running Keith Black 356 Hyper pistons. KB calls for a .008 multiplier for Street Towing and boosted applications for the top ring and .004 for the second ring regardless of application.

I filed all my top rings to .032 but my second row rings are all gapping out of the package at .024 when KB specs .016. Hastings states they stay on the looser side to be safe.

This truck will tow and have plans to add boost, but don't want excessive oil consumption.

This is the first motor I have put together and want to do it correctly.

Should I get a different set of file to fit rings to get my gaps dialed in per Keith Black or will the .008 be negligible? Seems like you read 10 different sources and you get 10 different varying opinions. From ring manufactures to piston manufactures.......it lends itself to a lot of interpretation and confusion.

Thanks for anyone willing to shed some anecdotal experience and suggestions!

Thomas
 
RustyRatRod said:
Send it. It'll be fine.
Click to expand...

Thanks for the quick reply!

Yea, the more I read the more conflict it seems I find. Seems there is a school of thought that suggest 2nd ring gap should exceed the first to prevent pressures becoming trapped and ring flutter occurring.

Probably be best just to make sure the gaps are consistent and run it!
 
I usually set the set ring at .022 on a 4.03 bore....close enough
 
Initially, in my 367, I used the .065 ring-factor on my 4.04 KB-167 hypers. For several weeks, I experienced overheating and loc-ups at shutdown, sometimes having to wait more than 20 minutes until the starter could crank it. After trying several starters and what-not, I pulled the engine and;
had the bores honed another .0005, and
opened the top gaps to the .008 factor, and
added .002 to the second rings.
This cured BOTH the overheating and the loc-ups.
After warming up the engine I did a LeakDown Test @the usual 40psi, and found the leakage almost too small to read. So I readjusted the test pressure to 80psi, and still had less than 2% on my gauge. The cranking pressure was over 185psi.
I called it a win-win and never looked back.
Like Rusty says;
RustyRatRod said:
Send it. It'll be fine.
Click to expand...
 
if you’re going to add boost gap the second ring a little larger than the top. It’s to keep from unloading the top ring when the pressure gets stuck between them. You will not see any appreciable difference in cylinder pressure or leak down.
 
I do remember Hastings were the go to rings for Mopar back in my day. Some suggested it was the higher nickel content having something to do with it. Whatever, they were popular with the Chrysler crowd.
 
You could back the gaps out to .100" and not see an appreciable difference in leak down. The gaps are not responsible for keeping compression gasses in. The ring finish and tension is. When you have a broken ring, for example. People think it's the break that allows gasses to escape. It's not. It's the fact that the break allows that part of the ring to relax and lose contact with the cylinder and become unsealed there. It's all about the ring tension and seal to cylinder, not the ring gaps.
 
Last edited:
... and the 2nd ring is an oil scraper- not a compression ring. It’s fine at .024.
 
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