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Piston Ring Source.

Posted by Jim Crank 
Piston Ring Source.
April 29, 2011 04:02PM
Does anyone know what firm makes those spiral wound piston rings? The ones that look like a kids Slinky toy. I need the name and e-mail address.
That is if they are even made any more today.
Had a set in my Stanley and they sealed better than any others we tried.

Re: Piston Ring Source.
April 29, 2011 05:14PM
smalley ring corp.

ouch, wait. You mean for sealing. Sorry Jim. You could grind the id/od to get the loading you want however quite easily. You'll loose temper but you don't care, you want to soften/anneal them anyway.


Edited 1 time(s). Last edit at 04/29/2011 05:22PM by kdc2.
Re: Piston Ring Source.
April 29, 2011 05:32PM
Rix Industries uses these in their comressors and owns patents on them. 707.747.5900 info@rixindustries.com

Karl Petersen
Re: Piston Ring Source.
April 30, 2011 08:55AM
I prefer using the step cut cast iron rings in the steam engines that I do. I buy them from "The Auto-Diesel Piston Ring Co." of Cleveland, Ohio. Telephone number (216)781-5200 info@adpistonrings.com or go to their wesite at www.adpistonrings.com The cost was about $25 each ring, made to your specifications. Delivery time is a little over two weeks time from placing the order, but if you are in a hurry, less than a week delivery is possible for a bit more money. Most of the steam cars on the road are using these step cut rings. David Nergaard is the one to put me on to them.
Re: Piston Ring Source.
April 30, 2011 10:22AM
These Sllinky type rings that I use so long ago have apparently disappeared. One outfit in Germany; but not here.
They seem to be made in both China and India; but I'll be damned if I ever would trust their metallurgy or quality control, too many bad experiences.
Available as retainer rings; but not piston rings. We need enough for four Dobles and spares.
Right Pat, step gap rings only and I have used Auto-Diesel before, good rings. Those I know where to get. Thanks everyone for trying


Edited 1 time(s). Last edit at 04/30/2011 12:04PM by Jim Crank.
Re: Piston Ring Source.
April 30, 2011 02:30PM
Clupet Piston Rings
Factory B, Solway Industrial Estate,
Maryport, Cumbria, CA15 8NF, UK

Tel: (01900) 818361. Fax: (01900) 818361 ..

Jim these people are well known for that type of ring, which are commonly known as Clupet rings in the UK. No web site but you could fax or phone them.

Re: Piston Ring Source.
April 30, 2011 11:52PM
Hi All,

These Clupet rings have come up a few times over the years.

Has anyone seen any data regarding their leakage rate as opposed to a step gap type of ring? Also, any data regarding the friction coefficient as opposed to step gap type rings? It wouldn't be any good if the friction was high enough to over come the lower leakage rate!

Does anyone have any personal experience in the performance difference between step gap or other types of piston rings and the Clupet types in their steam car?


I seem to recall that a few years ago you quoted some leakage rates from Doble's work. Do you recall if he tested multiple types of piston rings or what type of rings he advised one to use?

There was a loco company which used ringless piston valves and they claimed that when made properly they cost much less, lasted longer and were much less maintance intensive then the ringed piston valves that they made. They also claimed that the costs of producing and maintaining the ringless valves saved much more then the slight increase in steam usage as compared to the ringed piston valves. Their piston valves were larger in bore and longer in stroke then the largest pistons that were used for a Stanley automobile.

I believe that White also used ringless piston valves on their compound enigne with a "one finger" fit, the same as their flow motor.

The Rocket too had a "plug" piston with no rings. I have never seen an explanation as to why they didn't use rings for it. Were they possible worried about the higher operating pressures of that engine or maybe they couldn't get their hands on rings big enough? It is all very curious!

Caleb Ramsby
Re: Piston Ring Source.
May 01, 2011 04:08AM
The Rocket too had a "plug" piston with no rings. I have never seen an explanation as to why they didn't use rings for it. Were they possible worried about the higher operating pressures of that engine or maybe they couldn't get their hands on rings big enough? It is all very curious!
Caleb Ramsby

I don’t beleave that, most likely came from the same book that said there were no spring eather.
Re: Piston Ring Source.
May 01, 2011 06:38AM
Odd bit of trivia to impress the crowd...

Re: Piston Ring Source.
May 01, 2011 11:13AM

In the Doble engineering notebooks, not the stuff SACA sells, Warren Doble ran tests on piston ring leakage. His tests showed a rate of 7 pounds per hour per inch of circumference.
All the Doble engines I have been into had ordinary end gap rings; but fitted very tightly. No doubt the engines had been re-ringed several times in their lifetimes.
White engines in 1909 had no piston rings at all. Later in 1910 the 40 hp and the last of the 20 hp cars had sleeves on the low pressure stage valve and rings.
Yes, a one finger push fit and a very close one at that. I had to learn that lesson the hard way.

Culpet in England has no known web site, so nuts to them and one outfit in Germany has those spiral wound rings; but says nothing about custom sizes. I don't like depending on one or two rather obscure firms when some years from now, a new batch of rings might be needed. Rather use a well known and good product that i can always buy.
There are firms in China and India who make these rings; but from sad past experience with their lousy metallurgy and quality control, I wouldn't touch them with a 50' pole.
We will use step gap rings from Precision Rings Inc. and of a recommended alloy for 900° steam.


Edited 1 time(s). Last edit at 05/01/2011 11:15AM by Jim Crank.
Re: Piston Ring Source.
May 01, 2011 10:16PM
Hey Jim,

I got curious so I looked up your old post on this issue, quote:

"The Doble notation about the leak rate of piston rings comes from some of their engineering notes. This was apparantly during the development (?) of the Series F engines, which were really more a Besler project than the Dobles.
They were looking at the piston valve ring leakage and the leak rate, I am thinking, was the reason SOME of the Series E engines and the F engines had four rings on each section of the valves and not the more usual three rings. They were looking at all engine losses.
On the E valve the added rings were next to the inlet section for admission to the HP cylinder, the outer rings saw a lot less pressure and some valves were left with only three rings there. Consider that the E engine's relief valves were set to blow at 850 psi on the HP and 450 on the LP.
Original engines all had step gap rings, some later that were dismantled had ordinary gapped rings, which do leak more than the step gap, probably some owners re-ringing and didn't use the original step gap rings.
Unfortunately, as you said, detailed test conditions were not recorded.
We do not know if the engine was running on the lab dyno, or if it was locked and the leakage thus measured. The best guess, since it would reflect actual use conditions, the engine was running at full power. The F engine was designed for 1500 psi and 850°F steam conditions.
Also, some engines had four rings on the HP piston and the LP was left with three rings, although Doble being Doble, this varied from engine to engine.
In all the Doble engines I have had apart, none of the valves were the same as any other. Constant experimenting."

Here is a link to the conversation:


So from what you said back then the 7 lbs per inch of circumference was most likely at the full boiler test pressure of 1,500 psi of the F type engine. It could very well also have been a test on the piston valve rings and not the power piston ring, any inkling as to which it would be?

How on Earth would one go about determining the piston or valve leakage on a running piston valved compound engine? There would be leakage from the inlet of the HP valve to its exhaust, from the powet to exhaust side of the HP piston, then from the inlet to the exhaust of the LP valve and the same for the power and exhaust of the LP piston! Even with a very accurate condensor hooked up and PV diagrams it just seems like there are too many variables involved for a running leakage test of such an engine. Maybe I am missing some simple tricks!


You could very well be right!

There has been a lot of garbage information floating around about the Rocket.

However if you look at the chart that Karl supplied on the thread that I linked to in this post the tight bare piston .002" gap gave very respectable leakage rates as opposed to the piston ring. However this was a 11 1/2" long piston and air not steam. . .

I saw the engine they have at the Smithsonian when I was about 10 years old and had no idea as to its later significance in my life or its importance in automobile racing in general! If they still have it there, in theory they could open it up and see if there is a piston valve or not. This is probably getting off subject a bit but wasn't it the 1906 engine that they ended up with and not the 1907 engine with its modified valves/valve gear?

I also ran across this interesting paper regarding leakage and wear between piston and slide valves of a loco operating in generaly Stanley road pressures. The discussion and data is between page 515 and 544:


Caleb Ramsby
Re: Piston Ring Source.
May 01, 2011 10:44PM
Here is a bit from Porta's investigation into leakage:


Caleb Ramsby
Re: Piston Ring Source.
May 02, 2011 12:55AM
Caleb noted, "However if you look at the chart that Karl supplied on the thread that I linked to in this post the tight bare piston .002" gap gave very respectable leakage rates as opposed to the piston ring. However this was a 11 1/2" long piston and air not steam. . "

Thanks for the reference, but the chart was kindly supplied by Scott Finegan. Such charts are limited of course to the exact conditions and characteristics of the hardware being measured.

I would still like to see what the company in England may have to say about the effectiveness of their spiral rings compared to stepped rings which we all seem to think work fairly well.

Karl Petersen
Re: Piston Ring Source.
May 02, 2011 05:43AM
If the engine in the Smithsonian came from the 1907 wrack, it most likely is not the same engine that set the 1906 record run. They broke a lot of engines and from what I have read, they had an engine failure before the run in 1907 and took another engine from the Vanderbilt on hand and changed it out before the 1907 run that crashed. Page 215 Kit Foster’s book.

Leakage past valves and pistons in single acting cylinders is a loss, but in a compound it get to be used at a lower pressure. I always liked compounds.

Re: Piston Ring Source.
May 02, 2011 08:44AM
From the Precision Rings, Inc website:

"STEP CUT : Used where two rings per groove are not practical. The step cut is used to prevent a direct flow path between the piston and cylinder. Cross section must be larger to accommodate strength to the steps."


So in other words, reading between the lines sideways, if two rings per groove ARE practical, then you can just use two rings per groove and forget about the step cut?

In fact, that would work perfectly with my engine. Just cut the ring grooves twice as wide [measured along axis of piston travel], and install a standard IC top ring and second ring in each groove, with gaps 180 degrees apart. This would be functionally identical to step-groove rings... at 1/5 the price of custom step-groove rings, for my engine at least...

Actually, since steam leakage would have to travel 180 degrees circumferentially around the piston, along the ID of the piston groove, instead of just a fraction of an inch radially/axially/radially around the ring, this would give _substantially better_ sealing than custom traditional step-gap rings...

Thanks for mentioning Precision Rings Inc., Jim!


Edited 1 time(s). Last edit at 05/02/2011 08:59AM by Peter Brow.
Re: Piston Ring Source.
May 02, 2011 09:01AM
That's what I did too Peter, two rings per groove, rotated and pinned so they can't rotate during operation. -Keith
Re: Piston Ring Source.
May 02, 2011 09:28AM
If youre gonna fuss this much about leakage,,,Please look to how round the rings are at fitting diameter,,,020 diff dia,,and ya can see daylight past the ring,,and clowds of smoke,,
Somehow I think these tests are flawd,,
There IS a break-in period for these old style rings,,so a test before milage would be ,,,,,,,totaly useless
Rod's old Packard 30 would bounce say 20 times and return to the same position,,no loss of air,,this on an UN-restored engine in 1954,, Cheers Ben
Re: Piston Ring Source.
May 02, 2011 09:33AM
Hi Keith,


I wonder how many of the Stanleys without step-cut rings have been fitted with this [better?] solution...

IC rings about half the (axial) width of step-cut traditional rings... looks good...

I will be most interested to hear how your rings work out...

Always a pleasure to see "my new" ideas already in successful use but just (previously) unmentioned in the literature. Less climbing out on an experimental limb for me -- it already works, so quit worrying Mr. Pete and just build it! Ran into this when I recently learned of Stanleys "modernized" with self-aligning bearings... I mentioned that idea to Bruce Green about 20 years ago, after he told me that engine flex "played havoc" with bearings, and got the impression that he thought I was nuts... he was right of course...

Nuts about _steam cars_... smiling smiley

Re: Piston Ring Source.
May 02, 2011 09:57AM
Hi Ben,

No pinning rings for me. Old VW rings, top and second, go in with gaps 180 degrees apart, no gaps at bottom [horizontal cylinders of course] ever for some reason ("manual sez" ), and rebuilders tell me they've never seen a ring rotated out of assembly position.

I also wonder how many Stanleys have been rebuilt with plain-gap rings, _one_ per groove... and if there's any real difference in power/economy/durability.

Right on about engine break-in!

"Gilding the lily" is one of the biggest hazards in steam cars IMO. Pardon my understatement.


Edited 2 time(s). Last edit at 05/02/2011 10:07AM by Peter Brow.
Re: Piston Ring Source.
May 02, 2011 10:36AM

We have two new Doble valves coming this week. Leftover from an earlier engine rebuild. Now, the question is, are these the ones with two rings per position or three rings? Forgot to ask; but delighted to get them whatever and not have to make them too along with matching sleeves. Being Dobles, they changed the design as usual. One engine had four very thin rings. If they have two thick rings, I will definitely investigate using two step gap rings per groove, and will definitely confer with Precision Ring Co. on this first.
I still would like to use those Slinky type rings if they were available and in custom sizes too, worked so very well in the Stanley.

Also the two sleeve drawings have two different IDs, naturally. The drawing says "Grind to tolerance". So just what machine then in the early 1920s could they have to do internal grinding of the valve sleeve?? Remember there was no CNC stuff then, only super good toolroom machinists, every single one of them.
Today I Sunnen hone the valve bores. That is why my OO White ran for 14 years of driving and those plug valves stayed tight. It's always something. Ben is right, the bore and the ring have to be absolutely round and the engine really needs to be run for hours to set the rings. Did this with the White in the driveway for two days just idling slowly.
And yes Ben, I do track down every single loss I can find and try to eliminate it, better water rate that way.

The big problem with worn Doble engines and ordinary end gap rings, is that when well worn, the ends of the rings have a nasty habit of snagging in the sleeve ports and breaking off, usually taking bits of the valve too. Then flying up the exhaust pipe and into the first stage of the draft booster and chaos reigns. This happened to Jay Leno's E-18. And why Dobles always originally had a long cone screen in the exhaust pipe before the draft booster. The guy who rebuilt the engine long ago, left the screen out or didn't know.
Which brings up the question of oil. Mobile Super Extra Hecla or Mobile One synthetic 140 w. gear oil? Brent and Jerry swear by the Mobile One and they should know.

My guess is that Warren locked a valve and maybe a piston too in place in a cylinder block and then collected the escaping steam and ran it into a condenser, then measured the water. But; the notebook did not say if this was the piston valve or the HP valve, or for that matter, both.


Edited 1 time(s). Last edit at 05/02/2011 10:40AM by Jim Crank.
Re: Piston Ring Source.
May 02, 2011 10:41AM
Hi Peter,

Since I can't have my piston in contact with the cylinder (water lube) I've opted for this design:
[www.coorstek.com] starting about half way down.

I actually issed them a po, but since they dragged things out past 60 days I cancelled and fab'd inhouse. 350 vs 2700$ was another reason.

Several reasons to pin for me. Their spring loaded systems are also pinned.

Re: Piston Ring Source.
May 02, 2011 12:34PM
Internal orbiting grinder,,is Heald Worcester, Ma, I think,, pronounced HEEL ,,,Ask around the Franklin boys,,,Their cylenders get too hard and ya cant bore em,,,Heald is way to go,,,If you need a smaller valve seat grinder,,[[poppet]] its Hall-Waterbury,,,or Hall-Toledo,,,antique tools but the very best,,These are also orbiting grinders,,,NOT,,,,NOT,,,honers,,,grr,,
Now why would annyone want a cnc thingie,,hahaha,,,,Ben
OOOps,,,There is somewhere a SAE paper on the rotation of non pinned rings,,
I have personally whitnessesd an engine that the rings had rotated,,There is a relationship of rev per to ring turn,,,Our present engineers never read about what doesn't work,,
also,,if you carefully remove the old good rings,,clean em and get 1 or more upside down from the original position,,,it will pass oil and loose compression,,,,,Cheers,,Ben
Re: Piston Ring Source.
May 02, 2011 02:05PM
We have two new Doble valves coming this week. Leftover from an earlier engine rebuild. Now, the question is, are these the ones with two rings per position or three rings?
Jim Crank.

Jim would or did they have three rings on all four positions or just on the two inner HP positions? Curious
Re: Piston Ring Source.
May 02, 2011 04:18PM
I have rebuilt about 20 Stanley engines. In two thirds of the engines that had used straight cut rings of two per groove, the rings had aligned their straight cuts with in the grooves. Yes, the rights do rotate if not pinned. The steam passing by their ring cuts, keeps their cuts aligned. Why use a step cut ring in a steam engine? The reason is because of the low RPM that the steam engine turns, it needs all of the sealing that it can get. The Stanley only has two ring grooves per bore, so it has to work as well as it can with what it has. Less leakage per stroke means less wasted water. With revolutions of about 660 or less per mile, the Stanley engine needs all of the ring sealing that it can get. More Stanley Factory Trivia: Type 7 Stanley engine. " After the ends of the pistons are smoothed off, the width over all should be 1 1/2" The piston should be made three to four thousands under the bore of the cylinder. The grooves for the rings should be 7/32 from the ends of the piston. This groove should be 374/1000 wide and 15/64 deep. The rings should be made 1/1000 over the bore of the cylinders, and then should be rubbed into the grooves. If the rings are found to fit too tightly into the cylinder, a slight amount should be taken off of the split of the ring...." My experience: (unlike an Otto cycle engine) In a steam engine, the cast iron rings are fitted into the cast iron cylinder with no ring end gap. A properly fitted steam engine piston ring should pass freely the full length through the piston bore, without binding.
Re: Piston Ring Source.
May 02, 2011 06:02PM
FWIW, the coorstek rings are both step cut and pinned 2 per groove. I kept the 2 rings and pinning, but axed the step cut. Doubt I'll do much testing below 500 rpm so I'm not worried at all about staggered straight cuts. Can easily do static isolated bleed downs isolating just piston rings. Can report.


P.S. The coorstek rings are polymer with service temp @ 550 f. Won't help the stanley at all and will limit my testing. Have to start somewhere.
Re: Piston Ring Source.
May 02, 2011 07:26PM
Ben, Keith, and Pat: Thanks for the information. I will pin the rings so they don't rotate. Classic-style steam engines are not like aircooled VW engines... nor is anything else...

Pat: Schick's Model 740 Stanley engine blueprints show 3.990 +/-.001 piston diameter for 4" bore. Too loose? Custom step cut rings shown in these blueprints, from American Hammered Piston Ring Co, which I think is no longer in business.

Re: Piston Ring Source.
May 02, 2011 08:02PM
Hi Keith,

Just checked out the Coorstek rings; neat stuff!

Re: Piston Ring Source.
May 02, 2011 08:31PM
The early valve had two thick rings per groove, the later one had three rings in their own grooves in all four places. Dobles used American Hammered Rings, had boxes of them.
Pat and Ben are right, they must be fitted with extreme care and total contact all the way around.
These coorstek (?) rings would not work when the Doble is run at 800°F. The other outfit does have many alloys and I need to call them and see what they would recommend.
Re: Piston Ring Source.
May 02, 2011 10:05PM
Hey Karl,

Thanks for the correction.

Hey Rolly,

We really need a time machine to see what was what with the Rocket.

Right on about compounds, they use their leaks, don't condense as much and can expand more. If they wern't so much more bulky, complex and expensive then a simple I would like them even more.

Hey Peter,

To pin or not to pin, that is the question. I have read of those pins sheering off during use and not always leaving the engine quitely! This was in IC engines if I recall correctly and it may have been from the more agressive gas pressure spikes and piston speed then anything else.

Hey Ben,

Any clue as to why the Packard held its pressure so well? Possibly "just" experts who cared about what they made and an owner who cared just as much?

Hey Jim,

Good stuff Jim. In regards to performance what difference was there when you installed the slinky rings in your Stanley? Did you redo the valves at the same time or anything else that would have effected the performance?

For the Phoenix I recall that Abner noted leak rates of 30 to 50% of total steam used when in the early prototype stage. He seemed to indicate that this was from the very high steam temperature and improper bushing/ring materials. Later in notes stated that it was gotten ahold of but not to what extent. The cylinder cooling did seem to work though.

One study that I read regarding diesel engines was a test of a 3" bore cylinder and its upper cylinder wall temperature ran from 440 - 1,070 deg F, another study had the cylinder wall temp at 600 deg F, the head and piston running a bit hotter then the cylinder wall. I wonder just what temperature those diesel rings are made to operate at.


Really great info there!

I am suprised that the original engines were made so tight! Did any of the engines that you have restored have their cylinders worn oval?

Caleb Ramsby
Re: Piston Ring Source.
May 03, 2011 03:28AM
I took these photos last night in my shop, Bryan piston valves rings and pistons.
There is room to add a third ring to the valve face. But Jim the Doble valve face is narrower, I believe, I could see three rings in the same grove or two but not three each in its own grove, unless they were very narrow rings, but then I wouldn’t like the narrow ridge spacers to hold them. Don’t know enough about the Doble.

open | download - Doble E Valve and sleeve Model (1).pdf (59.8 KB)
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