The Steamboating Forum

Hi Steamboating friends

I am editing for publication the story of my friend Chris Doughty's boat build. I have got to the stage where he is discussing the engine, a Stuart Turner 5a that he had been given by one of his mates. In discussing the engine he suggests that he would have fitted "Courflex piston rings". Does anybody know of these as Google seems too keen to sell me stuff rather than return answers to my questions?

I recall from my youth using Cords piston rings and wondered if Courflex is a particular version of Cords since the original firm is now a subsidiary of some multinational.

Regards

Pete

I see old Cromflex piston rings, but nothing named 'Courflex': https://trademarks.justia.com/715/99/cr ... 99043.html

- Bart

perhaps "Clupet Rings"?

Peter,

are there any pictures of "Courflex piston rings"? That will help a lot for finding a reasonable answer.


Best
Dietrich

About a zillion small gas engines have a 2.25" bore. They've been working well for me.

Like these: https://www.ebay.com/itm/380211780861

Mike

Hi Everybody

Many thanks for your contributions.

The problem that I have is that posthumous editing means I cannot ring up and ask the author what he meant. Sadly, there is no photograph of the rings that Chris mentioned. He was a motor engineer at one point in his career so I am guessing that the brand was from that 'stable' so to speak.

My reference to Cords rings is dragging memories back from around 1965 when we late teenagers were very much into ways of improving the dire and rusty motor cars which were all that we could afford at the time. I ended up never using them as my Dad and and his garage owning mate said that I would be much better to go for a half engine as that would be better and quicker. That was probably because he wanted the space in his garage back for more lucrative work. My memory of Cords rings is that they were very like the rings that Fred has illustrated above. However, I distinctly recall that they were a similar sort of spiral, but not as fat. My guess is that they were made of flat spring steel. However, that was a very long time ago so my memory could well be wrong.

Regards

Pete

Sorry. I missed that this wasn't an active construction project.

That said, using anything but cast iron in this application is just asking for trouble. In my humble opinion (snorting in the background from my wife).

Mike

Peter,

unfortunately I don't know the context in which you work, so it's difficult to give good advice. I have used gray cast iron piston rings from engine construction in all of my current steam engines. But because they have a small gap at the joint, I use two pieces in a groove that are offset by 180° from each other. Because the piston ring groove was too deep for the new piston rings, I made a splited filler ring (not shown).

Here are two pictures of how I did it on my MARTIN steam lorry.




--
Dietrich

Hi Everybody

Thanks for the latest posts and I do like the double rings idea Dietrich.

Mike Rometer has sent me a few words on the issue within other correspondence. He sides with Mike's view on cast iron rings:

"'Back in the day' there were many, many Patent rings, all claiming this or that dubious property, about the most common one that is left is the Clupet, but I still believe any benefit is totally notional. From my experience with steam there is no real improvement to be had over the common or garden compression type ring. What many fail to realise is that if an engine is poorly performing due to ring wear ANY new ring will show a massive improvement so when they've fitted their overly expensive alternative ring, they lay all of the improvement at its door. I never heard of any manufacturer fitting anything other than standard rings at the factory, which surely suggests that there is little or no extra to be had elsewhere? I remember Cords, but not Courflex."

I think I will go back to the article I am editing and insert a foot note to suggest that the rings named are no longer available and that many such patent rings have been made but the majority do no better than the traditional cast iton ring in the context of the ST 5a.

Thank you all for your contributions.

Best wishes

Pete

Even automotive manufacturers still use conventional split piston rings... albeit quite a bit thinner than what we're used to, with higher cylinder pressures and temperatures, and higher standards for parasitic losses due to friction... just saying