Oil Control O-Rings - which are better?

[Pete_89T2]

Subject is the general question - I'm leaning towards just using the stock Mazda OEM O-rings on my build, because they are a well known entity and have a durability track record. But there are a few aftermarket options out there too, e.g., Atkins Viton rings, and similar Viton rings that can be sourced from McMaster-Carr and elsewhere.

Was curious on what the experienced builders are using and why? Pros & cons of using stock Mazda vs. a specific aftermarket alternative?

[RETed]

Silicone has a slightly higher heat tolerance than Viton.
Viton has superior resistance to petroleum products.
It's a toss-up between the two.

Silicone tends to swell when exposed to oil.
This is why you find "sqaure" o-rings on long mileage motors.
Viton tends to keep it's shape better under exposure to oil.


-Ted

[t_g_farrell]

Stock because I bet a lot more R&D went into them, like 40 years worth.

[C. Ludwig]

^ What he said. Also, I've never had a failure with the stock green rings. Lastly, I've had a couple customers provide alternate rings from various sources and they never fit correctly. Just like the coolant o-rings, I always say, if you're burning up o-rings, you have a bigger issue than the o-ring material you used.

[RETed]

Just a data point...

I've seen the green silicone o-rings disintegrate.
This was on a very high mileage 13B engine - over 200,000 miles.
The green silicon o-ring cracked into little segmented pieces - about an inch each section.
Each piece could be then squished between your fingers; the consistency was like a piece of cheese.

We ended up with the car with unknown history.
We can't confirm if the engine had been overheated.
We can't confirm if the engine has been frozen - this was in Sacramento, CA.

The engine was torn down because of excessive oil smoke, especially at higher revs - a sure sign of oil control ring failure.
This was a non-turbo FC.
All other seals were intact - water jack o-rings, inner and outer.
Almost everything else internally looked okay.
We replaced soft seal and apex seals (which were all under spec) and put back the engine for the rebuild.


-Ted

[chibikougan]

It was running Mazda OEMS and they where fine after the whole maybe 2k miles.

[Pete_89T2]

Thanks for the input guys, I'm going to stick with the Mazda rings.

Originally Posted by chibikougan

It was running Mazda OEMS and they where fine after the whole maybe 2k miles.

I probably could have reused those rings; they still looked & fit like brand new... But my general rule of thumb on rebuilding anything is if it's a soft/rubbery part, chuck & replace it. That plus I may have nicked them while removing for cleaning the rotors/metal rings & springs, or may have exposed them to cleaning solvent during the process.