Piston ring question Napier second ring

General engine tech -- Drag Racing to Circle Track

Moderator: Team

hoodeng
HotPass
HotPass
Posts: 1092
Joined: Sat Mar 04, 2017 6:53 pm
Location: South Australia

Re: Piston ring question Napier second ring

Post by hoodeng »

Is that top coating compatible with drilling?

Cheers.
LSP
Pro
Pro
Posts: 362
Joined: Tue Mar 16, 2010 12:33 pm
Location: Charlotte

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
Member
Member
Posts: 75
Joined: Sat Feb 08, 2020 4:54 pm
Location: 44090 Ohio

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.
User avatar
MadBill
Guru
Guru
Posts: 15024
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

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.

Happy is he who can discover the cause of things.
RCJ
Expert
Expert
Posts: 802
Joined: Wed Jul 25, 2007 6:15 am
Location: Oklahoma

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
Expert
Expert
Posts: 731
Joined: Sun Feb 28, 2010 8:49 pm
Location:

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.
engineguyBill
Guru
Guru
Posts: 1264
Joined: Fri Feb 26, 2010 11:15 am
Location: Gold Canyon, AZ

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

Perfect Circle Doctor of Motors certification
SAE Member (30 years)
ASE Master Certified Engine Machinist (+ two otherASE Master Certifications)
AERA Certified Professional Engine Machinist
User avatar
MadBill
Guru
Guru
Posts: 15024
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

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.
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.
jed
HotPass
HotPass
Posts: 875
Joined: Tue Nov 18, 2008 4:18 pm
Location: Dallas

Re: Piston ring question Napier second ring

Post by jed »

Good call bill
swampbuggy
Guru
Guru
Posts: 1575
Joined: Mon Apr 04, 2011 8:54 pm
Location: central Florida

Re: Piston ring question Napier second ring

Post by swampbuggy »

The price of Wisdom is Age...right Bill ? :D Mark H.
User avatar
MadBill
Guru
Guru
Posts: 15024
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

Re: Piston ring question Napier second ring

Post by MadBill »

All too true. I need to type faster while I'm still extant, to disseminate as much as I can of all I've learned (and not yet forgotten) in 77 years... 8-[
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.
Mark O'Neal
Guru
Guru
Posts: 1649
Joined: Tue Mar 06, 2007 7:23 pm
Location: San Tan Valley, AZ
Contact:

Re: Piston ring question Napier second ring

Post by Mark O'Neal »

I'd get a different set of pistons.
Mark O'Neal
Guru
Guru
Posts: 1649
Joined: Tue Mar 06, 2007 7:23 pm
Location: San Tan Valley, AZ
Contact:

Re: Piston ring question Napier second ring

Post by Mark O'Neal »

MadBill wrote: Thu Apr 08, 2021 11:43 pm All too true. I need to type faster while I'm still extant, to disseminate as much as I can of all I've learned (and not yet forgotten) in 77 years... 8-[
So....my name....so far.
Post Reply