Crankshaft nose bearing

[OG911]

Wayne suggests curil T be applied to nose bearing. Am set to reassemble, but not easy to find his preferred.
What function does it serve? Any suggestions as to alternatives?
Thx, guys.

[Jeff Alton]

Check out the "sealant thread".

Curil T is now Curil T2. Many, ourselves included, use Threebond 1211 there. The idea is to add additional sealing beyond the O-ring that is installed in that bearing. The reason? That O-ring can/will at some point dry up/shrink and cause a very common leak.

Cheers

[Henry Schmidt]

The issue with sealing #8 main bearing is more about #8 bearing saddle inconsistencies.
The glue is a simple way to add additional protection. We struggled for decades to avoid gluing an o-ring...yikes...bur after building 100s of these air-cooled engines, "better safe than sorry" seems a good rule.
Curil t has it's purpose but this is not our recommendation. We have been using Three-bond 1211 for 20+ years. If the saddle is round you don't need anything but most aren't and 1211 is capable of sealing as much as .010" where CurilT has limited gap performance under even low pressures.
It (Curil T) is great at preventing seepage especially where two surfaces are in constant flux. Cylinder base is a perfect example.

[JoeMag]

Below is very interesting phenomena...

The below is from my race motor that I tore apart last year. Had 100hrs on it. Look at how much the O-ring has been chewed up from venting air. I'm assuming it's because of the tight seal from the three bond 1211.

In the Klassic assembly video's he talks about to be sure there is nothing blocking the 'breather' line in the nose bearing. I can definitely see why.

[Dpmulvan]

A more pliable and a couple thousandths thicker o ring is the answer.

[stownsen914]

@JoeMag - did you have any leaks at the nosecone bearing before teardown?

[Henry Schmidt]

Originally Posted by JoeMag

Below is very interesting phenomena...

The below is from my race motor that I tore apart last year. Had 100hrs on it. Look at how much the O-ring has been chewed up from venting air. I'm assuming it's because of the tight seal from the three bond 1211.

In the Klassic assembly video's he talks about to be sure there is nothing blocking the 'breather' line in the nose bearing. I can definitely see why.

The bearing groove release oil pressure not air..

Too much glue improperly distributed. Very thin coat on the saddle and a secondary lip bead.