>My C-85 engine with approximately 650 hours since (questionable) major >indicates oil pressure no higher than 25 (on the line between yellow and >green) at cruising altitude of 2500 ft.
Not a problem and not uncommon at all for the 75/85's. My factory overhauled engine new out of the crate whjen hot (oil temp 170-200) only gives up 10-15 at idle and 25-30 at 2500 RPM. After frantic calls to the factory I am told that is normal for our engines and the 0-200's are not much better. The rep said the engine would run out a normal life easily with only 20 lbs of pressure at cruise since the engine needs more volume of oil vs pressure. He said 15lbs would even do if the volume was there and that the engines were designed with large oil galleries and passages as to NOT be dependent on higher pressures. >My mechanic has changed the >spring in the oil pressure relief valve and added two shims. He has also >reamed out the aluminum case where the oil relief valve fits for better >seating.... all to no avail. I'm afraid to continue flying the plane for >fear that the low oil pressure reading will cause permanent damage to >the engine so my lovely ERCOUPE sits and waits for relief while I boil! >Other than a complete major which is prohibitive at the moment can >anyone offer suggestions for solving the problem? > Just fly the plane. The bottom line I got from the rep was unless the pressure fell below 15lbs under full throttle or 5-7 at a 750 rpm idle there was no chance of damage to the engine. When asked how low it could run and still not fail inflight I was informed that the engines had been tested at 10lbs @ 2500 rpm for extended run times and never had a failure. Then he suggested I check with other owners of small continentals about their pressures. Most were at the same level if not a bit lower. Now I fly happy! Just for the record my WAY PAST tbo engine I sent back ran out it's last 1200 hours with about 18-20 at cruise and about 8 at idle. Hope this helps! Claude Wheelbarger six-two-zero W13
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