On Jun 24, 11:06 am, "Dick" wrote:
Previously this list advised a split seal is used on my flanged crank C85
and I then verified my case vent, hoses and air/oil separator system were
not blocked.

Since rather than pulling that spinner, prop, nosecone and cowl baffling to
install a new crank seal, would like to ensure I'm not missing something
easier. Recently a guy mentioned putting a gauge on the vent to determine
if case pressurized??

The engine compression has stayed at 79/80 hot for the last few years with
my oil usage not changing although the air/oil separator system may have
had a partial blockage for 6 months or so until I recently replaced the
hoses and cleaned it.

My question is: Once that front split seal leaks, will it ever stop leaking
and is there any test/check to ensure the case is not being over pressurized
to the point that a new seal would just start leaking??? (What causes over
pressurization?)

Thanks, Dick

The breather tube being blocked will cause pressurization.
Gases that get by the piston rings have to have somewhere to go and
the breather is there for them. Take the oil filler cap off and see if
you can easily blow air through the engine and out the filler. Clean
the crud off the tube end before you put your lips to it:-)
The seal will be shot. Not much question in my mind about
it. They get old and hard and shrink from the heat and start leaking.
They're fun to replace, too, because the seal goes on easily but that
tiny garter spring has to be put into it after it's on the crank but
before it's shoved into the seal bore and there's not much room to
work. A couple of needlenose pliers can hook the spring ends together,
and a pick or two are needed to work the spring into the seal. Bad
words are commonly employed, though they don't seem to help much.
Use a bit of adhesive sealant on the outer periphery of the
seal and in the bore itself.

Dan