912 Oil Pump Query

by Steve Newlands in 912 / 914 Technical Questions 11 years ago

Guys,
I recently posted about getting high oil temps on my 912 powered Medway EclipseR when two conditions are met - A larger passenger in the rear seat & warm weather. Apart from that she runs fine, just these two conditions set the oil temps rocketing over 130degrees. This has been an ongoing niggle with the previous owner and goes right back to when it was originally fitted 350hrs ago in 2002.
The previous owner fitted a slightly larger oil cooler which done the trick for a number of years, but refitted the original as the larger one developed a leak.
Since I'm giving the machine a full nut & bolt rebuild I wanted to get to the bottom of this issue (again, everyone just tells me to fit another larger oil cooler but I can't help but think that this is just disguising the issue).

Anyway, I dismantled the oil pump the other day and found these wear marks on the inside of the oil pump cover (pic attached). All the oil pump components seem to be in very good order - has anyone seen this type of wear before?

Thanks
Steve.

OilPumpCover912.jpg (You do not have access to download this file.)

Re: 912 Oil Pump Query

by Roger Lee » 11 years ago

Roger Lee

126 5.12k 4.53k

Many see higher oil temps with summer weather and a second passenger. 266F is high, but can be fixed.

If it's just surface polishing it's normal, but if it has big deep cut grooves then it needs attention. Because of your individual aircraft design the larger cooler may have been the way to go all along and is not disguising anything. I don't know what your prop pitch is set for WOT rpm, but unloading the prop to a flatter pitch will help too. I would first check the prop and get it set to fly WOT at your average altitude at about 5600-5700. This will help unload the engine some. If you see a lot lower rpms than this at WOT in flat and level flight that may be your problem. It's too course for your flying requirements. There is nothing wrong with just running the larger oil cooler. Make sure the carb needle clips are in the #3 position.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

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Re: 912 Oil Pump Query

by Steve Newlands » 11 years ago

Steve Newlands

3 7 0

Many see higher oil temps with summer weather and a second passenger. 266F is high, but can be fixed.

If it's just surface polishing it's normal, but if it has big deep cut grooves then it needs attention. Because of your individual aircraft design the larger cooler may have been the way to go all along and is not disguising anything. I don't know what your prop pitch is set for WOT rpm, but unloading the prop to a flatter pitch will help too. I would first check the prop and get it set to fly WOT at your average altitude at about 5600-5700. This will help unload the engine some. If you see a lot lower rpms than this at WOT in flat and level flight that may be your problem. It's too course for your flying requirements. There is nothing wrong with just running the larger oil cooler. Make sure the carb needle clips are in the #3 position.

Thanks Rodger for the reply.
The wear is surface polishing and isn't deep at all, but since the engine has this oil temp niggle I thought that maybe both issues are related.
The aircraft design has the oil cooler on-top of the gearbox, and the ex-owner was convinced that the position of the passenger diverted the airflow to the cooler - which all makes sense.
I haven't actually flown the aircraft yet, as soon as I took delivery I stripped the whole trike back to the keel-tube and rebuilt her. I should have her ready to fly next week so will know more about how she runs.
The ex-owner is a good friend of mine so am only going on his information.

Steve.

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Re: 912 Oil Pump Query

by Roger Lee » 11 years ago

Roger Lee

126 5.12k 4.53k

I have seen installations where the oil cooler or radiator is behind a pilot or passenger and air flow is disturbed to appoint that it can cause higher than normal temps.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

Report

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912 Oil Pump Query

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