[KyleTownsend]

I encountered this same problem earlier in the summer. It turned out that I had a "compound" problem. First, there was a piece of trash under the oil pressure relief valve seat. This was evidenced by lower than normal oil pressure when the oil was hot and less viscous. Second, I had a partially blown seal in the prop governor. It took about a week to narrow everything down and get it fixed.

We thought we had the problem fixed several times. However, it was very hot and I was at Dallas Addison (read lots of ground running before you get to take off). Typically, about the time I would become #1 for takeoff, the prop. would feather. ARGH!

In my case, there was insufficient pressure in the hub to hold the prop out of feather at RPM's just above the point where the mechanical locks engage to prevent feathering (idling at around 1,000-1,200 RPM) when the oil was good and hot.

When we were discussing possibilities, I recall that the main bearing seal on the crankcase was mentioned as a possible culprit. I think this is what you checked for with the test that Continental had you do (I assume that the oil was plenty hot when you did the test???).

I also recall hearing that this was a somewhat common problem on the Piper Senecas which also have the IO360's.

Continental, and several others, recommended using a fairly heavy straight weight oil if everything else failed. You might consider this.


Good Luck!

Kyle

PS: My rear engine was recently overhauled as well. It was a piece of overhaul debris that was causing the relief valve problem. I also noticed that this valve sure didn't get overhauled as part of my overhaul. We ended up replacing several springs, etc. because of its poor condition. However, my main problem was the seal in the governor (it was an O-ring that was missing a little pie shaped wedge out of one side). I thought I would never get out of Dallas!