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Piston ring question Napier second ring

General engine tech -- Drag Racing to Circle Track

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hoodeng
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Re: Piston ring question Napier second ring

Post by hoodeng »

Is that top coating compatible with drilling?

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LSP
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Re: Piston ring question Napier second ring

Post by LSP »

Ohio Rob wrote: Tue Feb 11, 2020 4:38 pm Here are a couple pics of the pistons.
Gas porting has been suggested, but I have a 1/16” top ring. Thoughts?
CRG0690-5 and gas port the top ring - What I meant was to put the gas ports in the upper surface of the top ring itself, Total Seal can do that to any ring. Gas ports are of benefit to 1/16" top rings too, and the gas ports in the ring itself will also get some radial tension/friction out of that big 1/16" ring as well.
Ohio Rob
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Re: Piston ring question Napier second ring

Post by Ohio Rob »

Thank you LSP!
I wasn’t aware that gas port slots on the rings existed.
Great info. I’m going to call total seal in the morning.
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MadBill
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Re: Piston ring question Napier second ring

Post by MadBill »

While you're at it, discuss spacers to allow narrower rings.
Felix, qui potuit rerum cognscere causas.

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Re: Piston ring question Napier second ring

Post by RCJ »

How long does the napier ''Hook' actually last? I was dissembling an engine last night that I had no history with.I randomly put the top and second rings back in the bore to check end gap.The top ring was a little loose , as would be expected from wear.The second ring had over .100 gap.I can see the cast 2nd ring wearing more than steel upper ring ,but this is really the first time I checked gap on disassembly.Any thoughts ?
BlitzA64
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Re: Piston ring question Napier second ring

Post by BlitzA64 »

My buddy freshened up a 360 Sprint engine last year he had built, 1/16 rings. Changed over to the new Total Seal conform rings and it picked up. Talk to them about that package, seems to help.
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Re: Piston ring question Napier second ring

Post by engineguyBill »

RCJ wrote: Fri Feb 14, 2020 10:45 am How long does the napier ''Hook' actually last? I was dissembling an engine last night that I had no history with.I randomly put the top and second rings back in the bore to check end gap.The top ring was a little loose , as would be expected from wear.The second ring had over .100 gap.I can see the cast 2nd ring wearing more than steel upper ring ,but this is really the first time I checked gap on disassembly.Any thoughts ?
There are two styles of Napier second rings. The original design was a square cut groove at the bottom of a flat-face ring, then the original design was improved to include a tapered face on the ring which resulted in a more prominent "point" and much better scraping properties. Modern Napier design is based on a "hook" design wherein the inside radius of the groove machined into the ring is curved, which results in a much sharper point and better oil scraping. The Napier second ring is typically manufactured from grey iron material, although some ring manufacturers offer these rings made from ductile iron and steel. The second ring is not exposed to high temperatures and typically is bathed in oil, therefore wear is not usually an issue with these rings and grey iron holds up very well.
I don't think your .100" gap on the second ring is caused by wear, more likely the rings were installed with that much gap.
Bill

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MadBill
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Re: Piston ring question Napier second ring

Post by MadBill »

Because a modern Napier ring face is tapered, wear can best be judged by noting how wide the shiny contact zone is.
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Re: Piston ring question Napier second ring

Post by jed »

Good call bill
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