Front Bearing Oil / Breather Hole

[Brian Sorgente]

Hi guys,

I've got an old RX-21 engine that was converted to an outboard and I could never get it to shut down on the bench / coming off the water. I knew it was pulling air from somewhere and later realized it was breathing through the front bearing, turns out the hole going from the intake to the front bearing isnt plugged like it should be.

I want to plug it back up and was wondering what i should use. I was thinking either a dowel pin or just some JB weld? Anyone done this before?

Brian

 

[Brian Sorgente]

This is the hole I am referring to. Anyone?

 

[Tim_Duggan]

I plug them with Devcon aluminum epoxy after cleaning the case with acetone.

 

[Brian Sorgente]

Thanks Tim.

 

[Brian Sorgente]

I plug them with Devcon aluminum epoxy after cleaning the case with acetone.

Do you happen to know the devcon number you use?

Brian

 

[Tim_Duggan]

Not off hand, but will have a look when I get home. I've had that stuff for years and years and years......

 

[Tim_Duggan]

Brian,

the product code on the stuff I use is S5/52345

 

[Brian Sorgente]

Thanks Tim!

Brian

 

[Neil LaGarry]

I assumed it was for oils getting into the front bearing housing. Drawing in air /oils/ fuel by back pressure. I may be wrong too If the front bearing goes premature then you know.

 

[RodneyPierce]

Ol' Jerry Wyss used to plug the thunder tiger motors with JB weld. I never once cashed a front bearing on one of his motors.

 

[Tim_Duggan]

Ol' Jerry Wyss used to plug the thunder tiger motors with JB weld. I never once cashed a front bearing on one of his motors.

I wonder where he got that idea from?

Neil,

The front race still gets plenty of oil with the hole plugged. Collet drives and belt starting are harder on front bearings than plugging the hole. In some engines only the buggy versions have the feed hole where as the On-road and marines have it plugged.

 

[Brian Sorgente]

I did some searching on IW and the only post I could find on it was from Andy Brown a long time ago. He said pretty much the same thing:

"Closed for boats, Open for cars. In the cars the hole DRAWS excess oil away from the bearing so it does not leak out onto the clutch.

Oiling gets to the front bearing by way of the crankcase aroung the crakshaft, not by way of the small hole under the carb."

Thanks guys!

Brian

 

[Tim_Duggan]

Yep, plus the buggy engines idle better when the car is upside down (crashed) thanks to a crankcase induced lean.... see post #1.

It robs torque though and is more obvious on engines with a poor crank to crankcase seal. (Why plugging works wonders on early Thunder Tiger outboard engines)