jamdfingr
Well-Known Member
Hi All,
Went to fly the plane the other day, warmed up on the ground with a few high speed taxis and then hit the throttle to go. Got to about 300ft and power started to fail on the engine. Lowered the nose, hit fuel booster and reduced throttle while managing to turnaround and line up back on the runway. Engine cut about 50ft off he ground and I managed to pull up on the runway before the fence with 30ft to spare. Not fun.
Went out today to check/test the engine and couldn’t fault on the ground. It all felt and looked good so I started it up and it would run up all the way to 3400rpm with temps and pressures in the green. Shut it down and check valve clearances and found a couple a bit tight but nothing to complain about. Ran it back up again trying to see if it would fault and just as I was thinking bad fuel, it suddenly dropped manifold pressure, chts shot up and oil pressure dropped quickly with rising oil temp.
I backed off the throttle and let everything settle down again and was able to then get it back to 3100rpm and watching as the oil pressure was slowly dropping out, then came a point the manifold dropped and the engine began to lose power again.
So am not sure what is going on. I get the feeling that as the oil temp rises, it is losing oil pressure which reduces lubrication film. As this starts to drop away, the engine load from the lack of lube film is then increasing which is dropping out the manifold pressure. This in tern starts to further reduce oil flow around bearings and ultimately the lack of flow to the cylinder heads is causing immediate jump in CHTs.
I thought of icing but it’s a rotec tbi and I doubt I would get the oil temp jump, just a rough running engine.
Anybody have any other ideas on what to test/inspect before I start pulling the engine down for inspection and overhaul? It must be bleeding internally somewhere which escalates as the oil thins out from heat.
For note, it is an Aeropower 2007cc with rotec tbi. Has oil cooler on top and a cooling plenum over the cylinders and cooler. Engine hours are only about 40.
Any thoughts or ideas would be appreciated. Will start with a drain of the oil to see if there is any bearing material in there to identify if they have spun.
Cheers,
Luke
Went to fly the plane the other day, warmed up on the ground with a few high speed taxis and then hit the throttle to go. Got to about 300ft and power started to fail on the engine. Lowered the nose, hit fuel booster and reduced throttle while managing to turnaround and line up back on the runway. Engine cut about 50ft off he ground and I managed to pull up on the runway before the fence with 30ft to spare. Not fun.
Went out today to check/test the engine and couldn’t fault on the ground. It all felt and looked good so I started it up and it would run up all the way to 3400rpm with temps and pressures in the green. Shut it down and check valve clearances and found a couple a bit tight but nothing to complain about. Ran it back up again trying to see if it would fault and just as I was thinking bad fuel, it suddenly dropped manifold pressure, chts shot up and oil pressure dropped quickly with rising oil temp.
I backed off the throttle and let everything settle down again and was able to then get it back to 3100rpm and watching as the oil pressure was slowly dropping out, then came a point the manifold dropped and the engine began to lose power again.
So am not sure what is going on. I get the feeling that as the oil temp rises, it is losing oil pressure which reduces lubrication film. As this starts to drop away, the engine load from the lack of lube film is then increasing which is dropping out the manifold pressure. This in tern starts to further reduce oil flow around bearings and ultimately the lack of flow to the cylinder heads is causing immediate jump in CHTs.
I thought of icing but it’s a rotec tbi and I doubt I would get the oil temp jump, just a rough running engine.
Anybody have any other ideas on what to test/inspect before I start pulling the engine down for inspection and overhaul? It must be bleeding internally somewhere which escalates as the oil thins out from heat.
For note, it is an Aeropower 2007cc with rotec tbi. Has oil cooler on top and a cooling plenum over the cylinders and cooler. Engine hours are only about 40.
Any thoughts or ideas would be appreciated. Will start with a drain of the oil to see if there is any bearing material in there to identify if they have spun.
Cheers,
Luke