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Re: 4.380 rings in a 4.372 bore ?
[Re: hemienvy]
#3228621
04/22/24 05:26 PM
04/22/24 05:26 PM
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Joined: Aug 2009
Posts: 2,042 Mooresburg, Tn
'72CudaRacer
top fuel
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top fuel
Joined: Aug 2009
Posts: 2,042
Mooresburg, Tn
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The factory used to recommend rings be no more than .010" larger than the bore and be filed. The only one I did was a factory .020" over bore 318. I used .030 over rings and filed them to fit. This was in the 1980's and they only place that I could find .020 over rings was order them from the dealer at about $95, I got .030 over rings from NAPA for about $30. To my knowledge, the engine is still running today. We routinely use rings that are .005" over (and file fit) on race engines. Brian
Last edited by '72CudaRacer; 04/22/24 05:26 PM.
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Re: 4.380 rings in a 4.372 bore ?
[Re: Al_Alguire]
#3228644
04/22/24 07:59 PM
04/22/24 07:59 PM
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Joined: Jun 2016
Posts: 906 Washington
hemienvy
OP
super stock
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OP
super stock
Joined: Jun 2016
Posts: 906
Washington
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OK, well now I'm inclined not to use these rings.
However, I have a related question.
I have an old set of Childs and Albert DuraMoly ZeroGap rings. The second ring (ZeroGap) and the oil ring say 4.375 bore, but the top ring is labeled 4.380. An old C&A ring catalog has the note:
For file fit rings, the part number de-codes as PREFIX - THICKNESS x BORE SIZE + .005
I think this means that the C&A top ring, labeled 4.380, is .005 oversize. Intended for file fitting into a 4.375 bore.
Now, the rings I was hoping to use are Sealed Power E-424K-060. However the note in the box does not say anything about file fitting these. So I put one ring in my new 4.372 bore and it does not go in unless I overlap the ends about 1 or 2 thou, negative ring gap ! Meaning that in a true 4.380 bore, they would have about .023 gap. File fitting NOT needed for these rings labeled 4.320+.060 ?
Thanks for humoring me, but the devil's in the details !
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Re: 4.380 rings in a 4.372 bore ?
[Re: hemienvy]
#3228653
04/22/24 09:09 PM
04/22/24 09:09 PM
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Joined: Aug 2009
Posts: 2,042 Mooresburg, Tn
'72CudaRacer
top fuel
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top fuel
Joined: Aug 2009
Posts: 2,042
Mooresburg, Tn
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Those rings are what is referred to as "drop in rings", fitting them is not required. However, they should be checked. Also, on file fit rings, the spec that is given is the MINIMUM amount of gap required, with more gap being "acceptable", to a point. A while back I was building a basically stock 390 ford and the drop in rings measured about .048". I called the ring mfg and was told that up to .055" would be ok.
Brian
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