On Sep 28, 12:23*pm, Andy wrote:
Both Pawnees at the local glider club suffer from leaking front
crankshaft oil seals. *One has had several oil seal changes and the
problem is not cured, the other started leaking within a few hundred
hours of a major overhaul. *One is in original fixed prop
configuration and the other was converted to fixed pitch from constant
speed. *Both engines will exceed oil pressure redline on a full power
takeoff when *the oil temperature is above low red line (bottom end of
green range).

So a few questions for those with experience of operating or
maintaining Pawnees -

Is front seal leakage common and if so if there a known cure?

On your specific aircraft, at what oil temperature can full power be
applied on takeoff without exceeding oil pressure red line?

What do you consider a minimum oil temperature for full power takeoff?

Do you think oil seal leakage is associated with high oil pressure or
only influenced by crankcase pressure?

The guys that maintain the Pawnees are looking for some answers, and
I'm tired of flying with an oily windshield, so any help appreciated.

Andy
We had a leaky crank seal about 800 SMOH that was replaced. Lyc O-540
engine. No problems since.
I have found that excessive oil pressure with full power at low
temperatures. Engine run up at 1800RPM with oil temp below 100F will
red line the oil pressure. For us it takes about 120F tobe. Able to
apply a full power takeoff.

High oil pressure could cause seal damage, we changed to steel braided
oil lines at overhaul so those are holding up well. We have had
problems with loose case bolts contributing to oil leaks and may have
also contributed to our leaky seal.

T