piston rings

[Dougie SwanParticipant @dougieswan43463]

Hi

Can anyone tell me where I can find some 21mm dia piston rings, are there any suppliers out there?

Thanks

Dougie

[Dougie SwanParticipant @dougieswan43463]

[JasonBModerator @jasonb]

Can you not make your own?

Or message this chap link

[Dougie SwanParticipant @dougieswan43463]

Hi Jason

I have made my own, some good, some not so good

I now have to make a new set of con rods and pistons for my engine,the one you helped with by sending me the cylinder head drawing.

I was hoping to buy some better quality ones to save time and inprove the compression

I tried the link you sent but just get an error message

Thanks

Dougie

[Dougie SwanParticipant @dougieswan43463]

Got the link sorted

Thanks Jason

Dougie

[Andrew TinsleyParticipant @andrewtinsley63637]

Hello,

Making your own is easy. There is some very good information on Supercool racing propellers website. I learnt most of the things I know from those articles.

There will be some argument about "springing" open the rings so they press against the walls of the cylinder. But it works for me. Rings that are dead size, do not work in model 60 racing engines, despite those experts who claim they do. Please note I have no other experience of making rings for anything other than racing 60 engines and 45 glow stunt engines. So what works for me may not for you if the engines are somewhat bigger than the ones I am used to.

Andrew.

NB when I say experts, I do not mean that in any derogatory sense, they are probably talking of larger capacity engines.

[Andrew TinsleyParticipant @andrewtinsley63637]

As an aside, the acknowledged expert in ring making was Frank Bowman in the US. he has passed on his business to someone else. I found Frank's rings to be a bit hit and miss, depending on cylinder wear, This altered the gap and hence performance. If Frank fitted the rings to your engine then results were always good, as he machined them to suit. There is a guy in the UK who makes rings (see Ebay). I would suspect the same thing applies. Unless you have expensive bore gauges, then it is difficult to specify exact size, best send the cylinders to be fitted by the ring maker.

Andrew.

[Fowlers FuryParticipant @fowlersfury]

Several years ago I purchased Clupet rings from Alan Smith, who at that time, I beleived to be the only manufacturer. It still seems he does little to promote his business but put "Alan Smith" Clupet rings into Google & you'll find many recomendations and much advice. Alan is (was?) a metallurgist and and offered valuable 'dos & donts' over the phone.

There were two problems; his delivery time was long, very long…..and the wall pressure exerted by his accurate & superbly made Clupet rings was ultimately found too great for my (steam) application.

[Martin CottrellParticipant @martincottrell21329]

Hi Dougie, that's a lovely looking engine. What model is it and are plans available?

Regards Martin.

[Dougie SwanParticipant @dougieswan43463]

Thanks Martin

It's mostly my own design based on the cirrus engine, it is made from bar stock

I dont have any drawings other than a couple of general arrangements that I made up just to get a rough idea of how it would look, the cylinder head is pretty much a copy of another model of the cirrus

Dougie

Edited By Dougie Swan on 03/09/2017 13:12:49

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