# Rings, Cast iron VS. ORings



## John38 (Jun 10, 2009)

I am new to this. I have about 12 models under my belt from Kits to bar stock engines. Have used both as compression ring would like other opinions.


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## rake60 (Jun 10, 2009)

Welcome to HMEM John.

I can't offer an opinion on the rings but hopefully
someone else where will.

Rick


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## kustomkb (Jun 10, 2009)

Model engine builder 15 has an article about it.

And a discussion here;

http://www.floridaame.org/discus/messages/6/91.html?1141699696

and here;

http://www.smokstak.com/forum/showthread.php?t=4632

My current build calls for viton rings but it hasn't run yet.


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## abby (Jun 10, 2009)

You fail to say whether your engines are steam or IC , generally in steam engines of around 1/2" to 3/4" bore and low superheat I would recommend viton o'rings , I use the "quadra lip " variety and have found them to be very reliable.
The fitting tolerances quoted by the manufacturer are for high pressure hydraulic systems and should be relaxed for model engines or they will be very tight. Silicone o'rings should not be used with steam.
For bores greater than 3/4" cast iron rings are generally prefered , high superheat temperatures will destroy most o'rings , viton can be used at temperatures up to 180°C.


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## doc1955 (Aug 27, 2009)

I personally used fine cast iron and turned up and heat treated my own for my engines.
I followed instructions I read way back in the Home Shop Machinist mag.
They are quite easy to make. I believe it was the odds and ends engine article that had the easy to follow steps.

Doc


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## cfellows (Oct 8, 2009)

I built a hit n miss engine with a 1 1/16" bore (yeah, I was aiming for 1 inch, but...). I have a plain old o-ring from the hardware store that's run several hours with no sign if giving out. 

Chuck


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## CMS (Nov 30, 2009)

I used viton o-rings in my hit & miss model, 1.250" bore.


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## Cedge (Nov 30, 2009)

CMS...
Viton is one of those things they never seem to remember to share with a newbie builder. I went through several types of O rings before I stumbled onto a box of Viton rings at, of all places, Harbor Freight. Once I made the switch I had no more problems. Chemical resistant, good to 500° and the resist wear much better than the others I tried.

Steve
Who can break iron rings by just looking at them....LOL


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