I noticed the after run oil leaked out of my motor around the flyheel and left an oil spot on my workbench.

Not suprisingly the motor ran like crap today. I took the motor apart and with the crank removed I can see light around the inner bearing race.

Can a seal failure on front bearing cause an airleak?

Thanks

Jamie

You have 995 post you should be able to answer that one.YES.It must have been one heck of a leak to be able to see light coming through the bearing.

Thanks for the smart!@# answer.

After run oil will leak out of a brand new bearing

Provk

With the fact that light can be seen around the rubber shield and inner race...Can I assume that is the cause of the possible airleak/tune issue.

Jamie

If you are have a tuning problem replace it, they dont cost that much anyway!!

Cheers

sory for that.But yes if you are having after run leaving a puddle of oil over night than I would say yes your front bearing is allowing air into the engine which will cause eratic tuning issues.I would replace it if it is leaking oil.

Some motors don't even come with sealed bearings. It's the close fit of the crank to the case that does most of the sealing. I still prefer a good double sealed TKO front bearing but if you are having tuning issues I would look elsewhere first.

Something I posted on another thread but it seems to be a popular issue.

The engines we use seal the bearing by liquid lock. If you want a big term for it "surface tension" (The a property of the surface of a liquid that causes it to behave as an elastic sheet). The tollerance between the crank and the case is critical to this working which is why loosing a bearing can make a engine non rebuildable. It is common for boat and some plane engines to not even have a seal at all. Our engines have a seal to keep dirt out of the bearing not seal vacuum. If you use after run oil or leave fuel in the crank case it will leak out the bearing over time. If the engine runs fine I wouldn't loose any sleep over it.