NoPistons -Mazda Rx7 & Rx8 Rotary Forum - what's the deal with "viton oil rings"?

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- - what's the deal with "viton oil rings"? (https://www.nopistons.com/rotary-engine-building-porting-swaps-55/whats-deal-viton-oil-rings-60071/)

Quote:

Originally Posted by Lynn E. Hanover' post='825376' date='Jun 21 2006, 03:58 PM

I have lost one set of stock "O" rings since 1980. And that time was my fault. Used rings from a junk engine that I know had been overheated. And they lasted two seasons before they gave up.

What's wrong with stock rings?

Lynn E. Hanover

Stock Black O-rings shrink.

I've had more than one engines Rotor scraper rings fall out when i've taken the engine part, They where very loose.

But saying that my next engine will be using the Stock Green Oil seals..

Quote:

Theproblem with the Atkins Viton seals is that they are measured in American, and Mazda uses a Metric measurement for the seals. So yes they fit like ****. the outer one is too small and is easy to cut when putting it on and the inner ones are too big and bunch in the scraper rings.

You can buy metric viton seals, they're just expensive. Standard viton oil seals in the sizes we need go for under $1 each. Metrics go for about $5 each. If you buy a full set of metric vitons for your oil seals you're spending $40 - which is what Atkin's set costs. If you buy four metric inners and four standard outers (IIRC) you're spending about $25. If Atkins is selling the same o-rings I bought for $25 for $40, then I don't feel so bad about using wrong-sized o-rings.