charles harbertwrote:

Ed, sorry to hear you're still leaking. Oil leaks in flight is something I'm
planning on totally avoiding in the future. The oil pump flow is directly
proportional to the rpm (positive displacement with pres relief), so the higher
the rpm the greater the flow. It sounds like your pres relief is set for 80 lbs
which would be the max flow point. Thus, you need to test at a high enough rpm
to maintain 80 psi (max pres). There is a significant difference in volume at
idle pres (20-30 psi) and high rpm which can cause the gbox drain system to
become overtaxed leading to oil being forced out the gbox rear seal.

This assumes that oil is leaking from the gbox seal, which is the usual place,
but you'll need to confirm this. I wrote before on this issue, but I would
suggest you try the following:

1.  As you indicated, test the engine at higher rpm (80 psi) to see if oil is
leaking by the r.seal. You also should test the oil pressure before the oil
cooler to be sure it's being relieved properly, and that there's not an
excessive pres drop across the cooler (assume you 80 psi is after the
cooler(normal position)).

2. Consider installing the NAPA scavenge (fuel) pump in a parallel line feeding
into the pan abv the oil level.

3. Consider installing a vent line in the gbox (as per latest Ross model), so
that oil pres cannot build up in the box. Use a clear plastic line to observe
oil level during test run. You can install this by just drilling and tapping a
1/8 or 1/4 NPT pipe fitting into the front gearcase just in front of the flange.
I'd suggest you do it about the 8 o'clock position. THis line should NOT fill up
with oil if the drain is working. The only ways to stop this is to restrict the
inlet flow further(not good), or increase the outflow.

I would bet that the r. seal is still okay, IF you relieve the oil pres in the
gbox. Did the seal you replaced look distorted? The only reason I think this
might work is that's the exact problem Dave Atkins and I had 6 months ago. Good
Luck.

 
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