Do any of you know what material the OEM rotor oil seal were made of? Were they Teflon like the nose oil seal, or were they Nitrile rubber or a different material?

Thanks.

They're either Viton or Nitrile. My advice is NOT to try to change them yourself. I've been there before.

I'm not planning on replacing them, I was just curious because I've never heard of one of them leaking internally.

They would normally not be noticed to leak to the rotor side simply because if they did, you'd just burn up the oil. Most people would never realize this.

In some instances, if they were to leak, they could positive-pressure the nosedrive under boost and cause the shaft seal to leak behind the pulley.

I've yet to see any reference to a failure of these seals or the bearings in the intermediate plate.

On the postive pressure Bill mentions....

Isn't that why they call the cap on the end of an S2 nosedrive the "breather cap"?

I didn't look that closely...to see if it was a vent or breather, however why would they call it a breather?

M62'* don't have that, M90'* do. They do vent under pressure. If you watch BadSSEi run on the track, you'll see puffs of oil from the SC oil coming out during the run.