Hi guys, we have a problem with an 0-360 in a Starduster. Having got the aircraft repaired and through our LAA system in the UK for return to flight we ran up about ten hours of testing etc. before changing the oil and doing a thorough check. Since then we have oil pressure problems, although we can't emphatically say the problem started at the oil change.
The engine is an elderly 0-360 C2D originally from a Hughes 269 but converted to conventional carb. The accident we rebuilt the aircraft from involved a prop strike so the engine was overhauled to our LAA standards and had 500 odd hours recorded before the incident. The oil pump gears and cover were replaced with new at the overhaul. Initial test and bedding in flights were fine, the engine runs well and develops plenty of power, smooth as well.
During test flights the oil pressure was nailed at 80 psi above 1500 rpm but we didn't specifically note the actual pressure below this. We are 100% certain it exceeded the Lycoming minimum of 25 psi at idle and seem to recall it being about 45 psi at idle.
Now, we can only get 58 psi at 2000 rpm, tailing off to 35 at 1000 rpm and only 10 psi at idle, this with an oil temp. of 150 F We are worried about running the engine in this condition so we've only done ground runs to get the oil temp. up to 150 F.
The oil pressure relief valve is the older fixed 'short tower' type and we've tried additional washers, new (and different) springs, new ball and 're-seating the ball' to no avail.
The sump strainer is clean as a whistle, the oil cooler hoses and the cooler itself have been flushed through twice and the Vernatherm looks OK. We drained the oil, and it looked clean, and then replaced the filter and oil. There were no changes to the pressures. The filter was cut open and there's nothing in it.
The filter is the standard spin-on type mounted on a B & C adaptor to replace the original screen type. This was done several years ago.
We've fitted a known accurate gauge directly to the crankcase pressure tapping without the restrictor elbow connector. The known gauge reads the same as the cockpit gauge +/- 2 psi.
Anyone any ideas ? All gratefully received.
Barry G
The engine is an elderly 0-360 C2D originally from a Hughes 269 but converted to conventional carb. The accident we rebuilt the aircraft from involved a prop strike so the engine was overhauled to our LAA standards and had 500 odd hours recorded before the incident. The oil pump gears and cover were replaced with new at the overhaul. Initial test and bedding in flights were fine, the engine runs well and develops plenty of power, smooth as well.
During test flights the oil pressure was nailed at 80 psi above 1500 rpm but we didn't specifically note the actual pressure below this. We are 100% certain it exceeded the Lycoming minimum of 25 psi at idle and seem to recall it being about 45 psi at idle.
Now, we can only get 58 psi at 2000 rpm, tailing off to 35 at 1000 rpm and only 10 psi at idle, this with an oil temp. of 150 F We are worried about running the engine in this condition so we've only done ground runs to get the oil temp. up to 150 F.
The oil pressure relief valve is the older fixed 'short tower' type and we've tried additional washers, new (and different) springs, new ball and 're-seating the ball' to no avail.
The sump strainer is clean as a whistle, the oil cooler hoses and the cooler itself have been flushed through twice and the Vernatherm looks OK. We drained the oil, and it looked clean, and then replaced the filter and oil. There were no changes to the pressures. The filter was cut open and there's nothing in it.
The filter is the standard spin-on type mounted on a B & C adaptor to replace the original screen type. This was done several years ago.
We've fitted a known accurate gauge directly to the crankcase pressure tapping without the restrictor elbow connector. The known gauge reads the same as the cockpit gauge +/- 2 psi.
Anyone any ideas ? All gratefully received.
Barry G
