Gapless rings working

jseng1

jseng1

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Nov 26, 2009
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Rebuilt my small block Ford recently and as usual it burned more oil than I liked. Ring gaps were correct and everything but still puffed a little oil on start up. So out of frustration I tore the thing down again and put in gapless rings. Now there is no oil burning at all. I used to have to check oil after uphill mountain haul trips - no more. I also have gapless rings in my Norton and have similar oil tight consumption improvement.

Send your 2nd rings off to Total seal and they'll machine it and provide an overlapping rail to cover the ring gap.
 
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I must be a lucky Norton owner as my Norton has never use oil or have ever topped up between oil changes, when I first brought it new it used a bit till I lowered the level from the top mark to 1/2 from the lower mark, even now running a smaller round alloy oil tank it still don't use oil between oil changes, but when I did the rebore ever so long ago I did the final hone to bore and piston under the recommended clearance, running Hepalite pistons 40 over, I also run a Lochart oil cooler since 1978 and a mix of STP in my oil, whether that plays a part, but it works for me, been running STP since 1982 in my oil, my Norton was an everyday rider most of its life and has well over 160k miles and has only been rebored once, rings were replace when I replaced the crankcases from hair line fractures around the main seal about 15 years ago.
I am no tec person and I do things as simple as possible, maybe patting my tank and thanking my Norton after I get home for a great ride has worked for me.
But Jim, love to build a motor with all your goodies if I had the money, you have some good stuff for our old Nortons.

Ashley
 
I'm looking forward to trying out the JS gapless rings on my 920 build, when I can find the time to get it finished!
Great to know that Total Seal will work with third party supplied rings - something I'm now considering for the Powermax pistons in my 750 Seeley.

But surely, isn't it the Oil Control rings which are primarily responsible for oil consumption; presumably these were also changed?

On the subject of oil consumption, I recall reading an article by the SAE which investigated the two scenarios of replacing the piston rings with and without honing a used bore.
It concluded that honing the bore just accelerated bore wear and increased oil consumption, whereas new rings bedded in just fine on used, un-honed bores.

Not getting into bores worn with a step at the top - just used bores in serviceable condition.

I was brought up believing that honing was an essential part of ring replacement on existing bores, and was called glaze-busting. It's been pointed out that 'glaze' indicates a hard deposition layer which would resist the bedding in of new piston rings, when what we're actually dealing with is simply a polished surface
 
B+Bogus said:
I'm looking forward to trying out the JS gapless rings on my 920 build, when I can find the time to get it finished!
Great to know that Total Seal will work with third party supplied rings - something I'm now considering for the Powermax pistons in my 750 Seeley.

But surely, isn't it the Oil Control rings which are primarily responsible for oil consumption; presumably these were also changed?

On the subject of oil consumption, I recall reading an article by the SAE which investigated the two scenarios of replacing the piston rings with and without honing a used bore.
It concluded that honing the bore just accelerated bore wear and increased oil consumption, whereas new rings bedded in just fine on used, un-honed bores.

Not getting into bores worn with a step at the top - just used bores in serviceable condition.

I was brought up believing that honing was an essential part of ring replacement on existing bores, and was called glaze-busting. It's been pointed out that 'glaze' indicates a hard deposition layer which would resist the bedding in of new piston rings, when what we're actually dealing with is simply a polished surface
Click to expand...
I seem to remember the powermax 750 pistons took a narrower piston ring?
Either oil control or compression?
 
Seeley920 said:
I think both. Same rings as the Atlas used. Shallower ring grooves
Click to expand...
I think it also applies to pre-'71 Commandos.

Triton Thrasher said:
The 2nd ring does a bit of oil scraping.
Click to expand...
Indeed 👍

Just done some digging...
Tapered second rings (with an identifying chamfer on the inner diameter) were introduced for better oil consumption (i.e., better than 200 miles per pint!) at Engine number 138973 (late 1970?), but could be retrofitted.
The 'S.E.' (Spring Expander) Oil control rings were introduced at engine number 146584 (mid '71?), but required new pistons for retrofitting.
This would indicate that only the oil rings were narrower, but both rings were changed.
 
B+Bogus said:
I think it also applies to pre-'71 Commandos.


Indeed 👍

Just done some digging...
Tapered second rings (with an identifying chamfer on the inner diameter) were introduced for better oil consumption (i.e., better than 200 miles per pint!) at Engine number 138973 (late 1970?), but could be retrofitted.
The 'S.E.' (Spring Expander) Oil control rings were introduced at engine number 146584 (mid '71?), but required new pistons for retrofitting.
This would indicate that only the oil rings were narrower, but both rings were changed.
Click to expand...

Thinking back to the last time I used Powermax, I think you're right.. The compression rings fitted ok, but I had to machine the oil ring grooves.. it's been a long time since I had to do that
 
When reading about ring gaps, I do wonder if people are not taking this all too seriously,? I recall several ref erences to a test done back in the 70's by AE, a major OE supplier of rings to the motor industry where they did a series of tests with increasingly large ring end gaps, starting at 25 thou, ending up at 65 thou. To their surprise, there was not a lot of difference in blow-by leakage or in oil consumption. I've not ben able to find the original test though, just references to it such as https://www.unionjack.com.au/blogs/blog/ring-gaps-vs-knowledge-gaps. Note though that these tests were all done with new rings on fresh bores. It seems probable that most of the oil control problems we see in service are due to the rings loosing their tension, and thus not sealing well against the cylinder walls.

They also mention the common practice of staggering the ring end gaps - in reality, it's meaningless (on a 4 stroke at least), since all the rings rotate on the piston at different rates. I actually did a test to prove this while training at Toyota's plant in South Africa. I know, I feel it's wrong not to do this on reassembly, and I usually end up at doing at least a bit of stagger on the grounds that a) it feels better, b) it cannot do any harm and c) it might have some effect on initial startup!

There's a very interesting (to me, anyway!) article at https://www.stle.org/images/pdf/STLE_ORG/BOK/OM_OA/Friction_Tribology/Lost in the Cracks (Or Where Oil Meets the Ring)_tlt article_Sept08.pdf where they discuss the actual causes of leakage, concluding that most of it seems to be coming past the rings due to the inability of the rings to conform to the distorted cylinder bore, as well as leakage due to the scratches on the cylinder walls.
 
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SteveBorland said:
When reading about ring gaps, I do wonder if people are not taking this all too seriously,? I recall several ref erences to a test done back in the 70's by AE, a major OE supplier of rings to the motor industry where they did a series of tests with increasingly large ring end gaps, starting at 25 thou, ending up at 65 thou. To their surprise, there was not a lot of difference in blow-by leakage or in oil consumption. I've not ben able to find the original test though, just references to it such as https://www.unionjack.com.au/blogs/blog/ring-gaps-vs-knowledge-gaps. Note though that these tests were all done with new rings on fresh bores. It seems probable that most of the oil control problems we see in service are due to the rings loosing their tension, and thus not sealing well against the cylinder walls.

They also mention the common practice of staggering the ring end gaps - in reality, it's meaningless (on a 4 stroke at least), since all the rings rotate on the piston at different rates. I actually did a test to prove this while training at Toyota's plant in South Africa. I know, I feel it's wrong not to do this on reassembly, and I usually end up at doing at least a bit of stagger on the grounds that a) it feels better, b) it cannot do any harm and c) it might have some effect on initial startup!

There's a very interesting (to me, anyway!) article at https://www.stle.org/images/pdf/STLE_ORG/BOK/OM_OA/Friction_Tribology/Lost in the Cracks (Or Where Oil Meets the Ring)_tlt article_Sept08.pdf where they discuss the actual causes of leakage, concluding that most of it seems to be coming past the rings due to the inability of the rings to conform to the distorted cylinder bore, as well as leakage due to the scratches on the cylinder walls.
Click to expand...
Didn't someone post on here about rebuilding triumph trident engines
Staggering the ring's 120°
And when the motor was stripped the rings were all lined up?
 
baz said:
Didn't someone post on here about rebuilding triumph trident engines
Staggering the ring's 120°
And when the motor was stripped the rings were all lined up?
Click to expand...

Yes, although not confined to Trident rings but any 4-stroke engine.

Rotation of piston rings

Piston rings lead a much more active life than might be thought. While we usually imagine that they only reciprocate in a motion defined by the piston, they also rotate during service. Such rotation has been the subject of many experiments and studies over the years, but this is not simply a...
www.highpowermedia.com
 
The 1st time I rebuilt the small block the Hastings rings had .025" ring gap. I thought this was too much so I called them and they reassured me that .025" gap was fine and it would not result in oil burning. They were wrong. It smoked and puffed at idle. So I tore it down and installed Deves rings with a tighter gap and the problem went away - at least to the point where oil consumption was normal compared to other motors and its didn't puff at idle.

I also built a VW motor for a friend that ran fine for years and suddenly started smoking. He said it would smoke a few days, stop smoking and then start again. When we tore it down everything looked perfect except that the ring gaps on one piston were lined up and pressure was blowing in a straight shot through the gaps (I was carefull to stagger them during the build but they rotated after a few years).

When you install total seal rings the first thing you notice is increased compression. Less pressure is leaking past the rings into the sump. In other words - "blow by" is reduced. You can have more blow by or less blow by - that is your choice.
 
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FWIW, Some years back we dyno tested several engines with standard rings gapped per spec and then removed the pistons/installed gapless rings. There was no difference at all on the dyno. We did the same testing with various ring gaps from min to rather wide and again, there was no difference in power output.
 
Why , in 4 stroke engines , are the rings not kept from rotating like in 2 stroke engines?
 
I never worry about ring gap uless the rings do not fit easily into the bores. If you buy rings which are too big for the bores, when they are compressed in the bores, they probably do not fit evenly around their circumference, so oil usuge is probably a bit high for a while. Most rebuilt motors are usually a bit slow at first. Then they loosen-up. You can be the greatest fanatic about clearances and still end-up slow. I do not take life so seriously. I run what I have and tune it to suit.
One thing of which we need to be careful -if there is a step in the bore and insufficient ring gap, it is possible to insert a piston into a bore and it might jam - the step can then make it impossible to remove the piston without breaking it.
 

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