leaky pushrod tube fixes ?

Traditional OHV BMW boxer engine which recently
developed a dribble of oil on one pushrod tube.

Replacing the rubber seal would probably mean
pulling the head and cylinder barrel to put the seal
in place, then replacing some O rings at the cylinder
base plus a head gasket then reassembling and
retorqueing the whole mess. Doable, but a PITA.
and probably a big chunk out of a Saturday.

I read one account where the owner had managed
to wrap plumbers string between the pushrod seal
and the lip in the pushrod tube to add some pressure
to the seal.

Anybody else tried this or any other wuick repair
technique ? If it did nothing more than fix the drip
for a few weeks until I found the time for a more
permanant solution, it would still be a very worthwhile
fix to me.

 

I've used plumber's tape (PTFE tape, we call it) on oil unions on a
Guzzi. It worked. Never tried it on a pushrod seal, but I can't see
you've anything to lose.

 

They all do that sir and if it's a 90 or a 100, it'll do it again very
soon.

It's not that bad - the last time I had to do it on an R80 it was
something like 2-3 hours IIRC. Well, either that or I was caught in a
beer-induced time warp.

It'll probably work if you can get it in deep enough (fnar).

Unfortunately if it's one of the bigger twins it'll only be
semi-permanent as they all seem to start dripping sooner or later.

 

I've actually had pretty good luck to this point.
High mileage R100GS. First pushrod drip of
this size that I recall. Possibly because it's recently
been fixed to the point where the other drips
are pretty well gone. This is a spoonfull or so
overnight.

Took a shot at it this morning using ordinary cotton
string. I'll see how it fares. This may be the result of
some recent abuse where the bike got run hotter than
usual.

Ever try Hylomar or some other non-hardening
sealant ? Seems like it might be worth trying.

Thanks

 

Fair enough. That's quite a lot, actually. IME once they go past "damp"
you're looking at "torrential" quite soon.

That certain did the oil seal no good, but then again they're not
exactly built for eternity anyway.

It's worth a try and I doubt it would do any harm. "Common wisdom" has
it that BMW stretched the engine a little too far when they went over
800cc and it seems that the thermal stresses conspire to turn the bike
into an oil dispenser.

 

You have to be careful applying Hylomar, if any excess squeezes out of the
joint into the engine it seems to gather up any crap it finds in the bottom
of the sump and then clots in the oil filter.

 

This actually worked well. A few turns of string
between the rubber seal and the metal lip on
the pushrod tube worked to push the seal a
little deeper into the recess where it sits.

No more leaks for the moment. I'll retorque
the cylinders this coming weekend and keep
an eye on it for a while. If it comes back, I'll
tear it down. If it doesn't, I'll hold off a while.