Piston rings

[andrew winksParticipant @andrewwinks64215]

Hi All

An often discussed topic no doubt but I have installed PTFE rings on gunmetal piston running in a cast iron cylinder on my 5' gauge locomotive. It ran perfectly on air years ago and still does so today. Just wondering what the group thinks about this method of sealing, I keep thinking its not really "kosher" as it should have CI rings. But she runs however it may be a different story when saturated steam instead of compressed air.

I did purchase some rings some time back with the intention of replacing the PTFE but I have read that gunmetal pistons don't appreciate CI rings.

Comments appreciated.

[andrew winksParticipant @andrewwinks64215]

[John BaguleyParticipant @johnbaguley78655]

Hi Andrew,

I started using PTFE rings years ago and never looked back but have only used them on gunmetal cylinders so far. One of the locos has very high superheat. I don't see any problem with using them in cast iron as you have.

John

Edited By John Baguley on 20/02/2015 10:24:59

[andrew winksParticipant @andrewwinks64215]

Thanks John, I've been mulling over it and I think I'll leave it as is and see how they last. I'm at the stage of construction where I've questioned a few plan designs, beefed up a few things here and there before the final home stretch of backhead fittings prior to first steaming. Cheers Andrew

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