Ring gaps for my 452

Posted By: BradH

Ring gaps for my 452 - 12/28/10 04:59 PM

This is the first time my engine will have been assembled w/ conventional file-fit rings since it was built waaaaay back w/ "gapless" stuff. The PBM-branded rings supplied by the local machine shop that did the re-hone on the cylinders are plasma-moly / reverse back-twist / standard oil tension in the 1/16", 1/16", 3/16" size.

I don't know if I should consider my combination "moderate" or "serious" for gapping purposes. Moderate would use .004 top / .005 2nd per inch of bore diameter vs. .0045 top / .0055 2nd. For a 4.380" bore, that works out to...
Top --> .004 = .018"; .0045 = .020"
2nd --> .005 = .022"; .0055 = .024"

Engine will be spun up to 7K RPM and run w/ 10.8 CR on 93-octane pump gas. Also, the top ring position is .175" below the deck.

Guidance requested.

Posted By: 440Jim

Re: Ring gaps for my 452 - 12/28/10 05:05 PM

Quote:

Top --> .004 = .018"; .0045 = .020"
2nd --> .005 = .022"; .0055 = .024"

Guidance requested.

My 2-cents. There isn't really anything significant to gain with tight ring gaps. It should be fine either way, but for high heat insurance, I would go about:

Top: 0.019-0.020"
2nd: 0.022-0.023"

My engine (higher CR, hp, etc) is 0.021", and 0.024" as I recall.

Posted By: 602heavy

Re: Ring gaps for my 452 - 12/28/10 05:34 PM

Here's my camp............

Top......0045 X bore=.020"
Second...0045 X bore=.020"...............top ring will 'see' more heat than second , added bonus being 2nd cast ring will wear faster than steel top.............

await the shooting match.

Posted By: Cab_Burge

Re: Ring gaps for my 452 - 12/28/10 06:56 PM

I use .020 to .024 on the tops and .024 to .028 on the second rings on all of my builds now since 2001 or so

Way better to have enough or a little to much end clearances than not quite enough, especially if you get the hankering for some squeeze or other power adders later

Posted By: 602heavy

Re: Ring gaps for my 452 - 12/28/10 07:00 PM

Quote:

I use .020 to .024 on the tops and .024 to .028 on the second rings on all of my builds now since 2001 or so Way better to have enough or a little to much end clearances than not quite enough, especially if you get the hankering for some squeeze or other power adders later

Well , lets gap em .007 right off the bat then.

........better steer clear of the molly type rings too.