This is the recommendation from Ultima engines for those running a belt primary to ensure a leak free operation. I might put some RTV on the outside of the steel case liner, but would not trust RTV on the splines. RTV could break off and get sucked into the bearing and into the motor and oil passages. That's my worry. Has anyone done this with a belt or wet primary?

 

Yes this is fine. I run the same setup and actually just finished doing this today. RTV is fine too use on the splines, it's the only way to stop leaks.

It's a common maintenance task as the heat and torque tend to wreak havoc on the silocine. I'm actually trying a Loctite high temp silicon those time around. I haven't had a lot of luck with the grey RTV.

Just don't use a **** ton of it and don't push it into the spacer too far. You'd have to shove it pretty far to get it into the bearing, and even if you get a flake back there it's soft and highly unlikely to ruin a bearing.