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Anyone install pre-oiler on a 912?

Piper J3

Well Known Member
I?m thinking with all the exposed oil hoses on a Rotax 912? has anyone ever installed an electric pump for developing oil pressure prior to engine start? We do the ?burping thing? to scavenge the crankcase but this does little to start oil migration to the vital parts. Just wondering?
 
Most of the Rotax 912 oil system does not have any pressure. Oil is sucked from the tank, through the oil cooler and then is pumped under pressure through the engine.
The only part that has any pressure at all is the oil return line to the tank, and that pressure is very low (only the pressure induced by crankcase blow-by).

I you want a happy engine for cold starts, probably your best choice would be to install the Reiff preheater.
 
Thermostate

If your goal would be a happy engine in colder times, I can recommend a Thermostate. I build one in my Kitfox (912 UL) for oil and one for coolant, and intend to repeat that on my '12, as well. Works perfectly! It just adds some hoses and sone extra attention for leaks the first hours or so, but it worked flawlessly from the beginning. Much quicker right oil temps (virtually no run-up times to heat the engine anymore) and water temps. there's a shunt involved in case the themostate fails.
 
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Hans, I agree completely with using a thermostat to speed up warmups and keep the engine up to temperature once running. However I think this thread was intended to address the situation of oil flow immediately on startup, when temps can be VERY cold in the northern climes. In order to ease starter power required and get the oil flowing quickly to provide good lubrication it is important to have a way to pre-heat the engine and oil. Here in upstate New York I find the combination of the Rieff preheater and the Aircraft Specialties oil thermostat works beautifully.
 
Thanks for all the info. My intention was to build oil pressure prior to cranking regardless of ambient temp. This is done on a lot of military reciprocating engines. P-51's have a pre-lube pump to protect and increase life of the Merlin.

I also posted this question in the Rotax forum and got this response:

It really isn't needed and if you do use a pump and the engine isn't running the the crankcase could fill and no oil will be returning back to the tank. You need crankcase pressure to return the oil.

The engines have been good on this side of the coin since 1989 and adding this most likely will cause an expensive repair if you blink at the wrong time. This one is probably better left alone.

Roger Lee
 
J3, do you have a preheater installed, or some other external way to preheat? That's really what you need, IMHO. Middle of the winter my Rotax starts right up like it's July!
 
The engine starts fine even at 30F. I'm using Mobil 1 10w-40 4T and it takes almost 25 seconds for oil pressure to pass thru 15 PSIG. This is what got me thinking about a pre-lube pump. Maybe nothing to worry about. Oil pressure in cruise flight is in the high 50's.
 
If you install the pre-heater I linked to in post # 2, you would have normal oil pressure almost as quickly as you do in mid summer.
 
The engine starts fine even at 30F. I'm using Mobil 1 10w-40 4T and it takes almost 25 seconds for oil pressure to pass thru 15 PSIG. This is what got me thinking about a pre-lube pump. Maybe nothing to worry about. Oil pressure in cruise flight is in the high 50's.

J3, if you want to be able to fly in the winter in Ohio, and you want to get the maximum life out of your expensive engine, you need to preheat. Period.

There are multiple ways to accomplish this, but the simplest is with an installed electric system like the Rieff.
 
I need to ask if the Reiff preheater can be powered continuously. In cold weather can it be plugged in 24/7? It has a thermostat so I think it should be OK. Thanks in advance...
 
Yes. Mine has been plugged in for nearly a month now. I check the temperature from time to time, it's stable. The thermostat works.
 
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