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Ring gaps for my 452 #890099
12/28/10 12:59 PM
12/28/10 12:59 PM
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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BradH Offline OP
Taking time off to work on my car
BradH  Offline OP
Taking time off to work on my car
B

Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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.

Last edited by Blew My Budget!; 12/28/10 01:08 PM.
Re: Ring gaps for my 452 [Re: BradH] #890100
12/28/10 01:05 PM
12/28/10 01:05 PM
Joined: Jan 2003
Posts: 16,924
NC
440Jim Offline
I Live Here
440Jim  Offline
I Live Here

Joined: Jan 2003
Posts: 16,924
NC
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.

Re: Ring gaps for my 452 [Re: 440Jim] #890101
12/28/10 01:34 PM
12/28/10 01:34 PM
Joined: Dec 2008
Posts: 1,200
UK
6
602heavy Offline
pro stock
602heavy  Offline
pro stock
6

Joined: Dec 2008
Posts: 1,200
UK
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.

Re: Ring gaps for my 452 [Re: BradH] #890102
12/28/10 02:56 PM
12/28/10 02:56 PM
Joined: Aug 2003
Posts: 43,157
Bend,OR USA
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Cab_Burge Offline
I Win
Cab_Burge  Offline
I Win
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Joined: Aug 2003
Posts: 43,157
Bend,OR USA
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


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Ring gaps for my 452 [Re: Cab_Burge] #890103
12/28/10 03:00 PM
12/28/10 03:00 PM
Joined: Dec 2008
Posts: 1,200
UK
6
602heavy Offline
pro stock
602heavy  Offline
pro stock
6

Joined: Dec 2008
Posts: 1,200
UK
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.







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