Oil thermostat on Rotax 912

[WWhunter]

How many guys are using an oil thermostat on their 912's? Is it really neccessary? I bought one while at Oshkosh last summer but after reading up on it (before installing), I am thinking I might just leave the engine as is. I basically wanted it to allow the engine to warm up a bit quicker in the cold climate Ilive in. Realizing that I already have a Tanis preheater on it, I probably don't need it. Plus, it is just adding weight nd complexity.

I have the engine removed and am debating wether or not to send it to Hal or MLS to have them look at the persistent ignition issue. I was able to find one wire that was hanging by a couple of strands. It was the red lead going into the rear of the engine. It is the same wire I had issues with a few years ago. Since the engine is off, I am replacing the water hoses and other rubber items. Figure it would also be a good time to install the oil thermostat, but as I mentioned, having second thoughts.

[AirFox]

Doug(Floog) and I have the same engine/prop combo and did a test a couple of weeks ago. We started up at the same time temp etc and ran the same startup RPM profile. On a warm up to 120 deg oil temp the difference in time was 30 seconds. I have the oil thermostat and Doug does not. I don't think the thermostat is worth the added weight and complexity. All other flight parameters with regard to oil temp are negligible.

Scott

[WWhunter]

Thank you Scott!! That was the findings that I was getting in my research. Basically, it was not worth doing.

[GuppyWN]

Doug(Floog) and I have the same engine/prop combo and did a test a couple of weeks ago...

What was the ambient temp?

[AirFox]

Start up outside air temp was 28 Deg F. We have been compairing flight temps and they are the same too. Both of us have shutters that cover our oil cooler.

[Dorsal]

Interesting thread, would be be curious if there is a bigger difference with the shutters open (assuming they were closed). I put the thermostat in when I built the plane (but no shutters) so have nothing to compare it to.

[AirFox]

On the ground the shutters don't make much of a difference. I've started the plane with it open and closed. There is not much difference. The shutter really shines when flying. As you know at altitude the oil doesn't get really warm. The shutter can warm the oil as much as 30 deg. I made my own shutter. You can also order one for the Rotax on ebay. Search Rotax 912 oil shutter.

[Slyfox]

sorry guys, I love my thermostat on the oil. I always see the same temps 180 or so. I fly a bunch in the winter, usually not under 25 degrees. for me plug and play is my game. meaning I jump in the plane, start it and go fly. no shutter to mess with, no worrying about the oil temps. I have a combined 2000+ hrs on two motors with this setup, absolutely love it. you guys want to tinker, go ahead.

[WWhunter]

LOL, I understand the 'tinker' comment as I am one of those types! My wife says all I ever do is tinker with stuff!!

Fortunately (unfortunately most will say) I live in the boonies, and it gets VERY cold here. Woke up to -30 yesterday and I had to leave early for a 330 mile RT drive to pick up a vintage snowmobile. Yes, it gets brutal cold here. Windchills were extremely low and the high temp for the day was -4!!

I am old enough now that I will not fly in those temps. I will occasionally fly in belwo zero temps, but generally in the 172 since it is better insulated and has a good heater. All the fabric covered planes I have owned seem to lose heat much faster than the old aluminum spam can does.

I'll probably end up installing the thermostat and put on the shutter. I usually have to tape over it but have had the days temp rise enough that I had to land and remove the tape. A shutter would be nice in this instance.

[Slyfox]

I consider myself a weiny. I went flying yesterday it was cold, like 12 degrees. windy yup, that too. It was 11 gust to 20 or so. I took the RV.
On the thermostat you don't have to have the shutter as well, the right thermostat will not let the oil even go into the oil lines to the cooler, the cooler is completely bypassed, having the thermostat will make sure no cooler or lines are in the flow. will be warmer on oil temps. my take

[jiott]

I too have the oil thermostat for my 912uls with 750 hours on it now. It seems, as Scott said, that it doesn't help much on cold warm-up. It seems like it did a better job when it was much newer. I am wondering if the little thermal element in the stat has failed, maybe yours too Scott, and it should be replaced. I know on cars that element seems to have a limited life. Any ideas on how to test it without disassembly?

[Slyfox]

this is my thoughts on that. are you using 100LL, that could gum up the thermostat. the other, if you think it may not be working quit well than by all means replace the element.

[kmach]

Most oil thermostats for the 912 don't fully shut off flow or bypass the oil cooler. They usually allow roughly a 10 percent flow when closed.

I would like to know a make and model of this one that totally bypasses the oil cooler.

I have been using a mocal oil thermostat since 2010, I remember it making a difference on warm up back then when I first tried it. It allows approximately 10% flow when fully closed, so you still need to block off a portion of the oil cooler inflight when it is "arctic". Not a big deal if the oil cooler is up in front of the gearbox. Aluminum tape works well.

[kmach]

What make and model of oil thermostats are you guys using ?

Are you guys using a coolant thermostat as well?

I use the thermobob coolant thermostat, it also helps with engine warmup and it keeps temps up inflight, very nicely .

[Slyfox]

not sure about the 10% still going through the oil cooler, could be I guess. I got mine from lockwood many moons ago. like maybe 14 years. Now for the coolant, nope. reason I don't is because I run my heat off the cooler. a bit of redneck in me. I run a plastic funnel off the back of the cooler and run scat hose off that into the inside and point it at my feet. free heat, than I cover the cooler with cardboard and a couple pocky ties from an automotive transmission cooler setup. works great, keeps my feet warm. no weight and no complexity with taping into the water.

[Dorsal]

I run both the oil thermostat from Lockwood and coolant thermostat, I think the engine warms up quicker but I know temps are very stable and predictable across a wide rage of flight conditions.

[WWhunter]

I already have the coolant Thermostat and will install the oil thermostat since it is already bought and paid for. The coolant thermostat I bought a few years ago through Hal Stockman. The oil thermostat I bought while at Oshkosh last year. I purchased it from Lockwood and it was $55.95. Be advised they do NOT include the hose fittings, even though the paper (instructions) state that they are included. It is just the thermostat and one must source their own fittings and clamps. They are just 1/2" brass hose barbs which can be purchased at any hardware type place. Or go custom or aviation quality and get some nice blue anodized fitting from JEGS or SUMMIT. ;)

[kmach]

Is there a make and model on it?

[jiott]

Just buy the oil thermostat kit from Kitfox. It includes fittings, etc.

[Dusty]

Here's the kiwi solution to slow warm ups and varying oil and coolant temps.Yes it's complicated but it's a fly and forget system .A typical days flying here can be a take off ar 10- 25c air temp,climb thriugh 0 to minus 10 then back to 10-25 on the other side of the island.
I installed a full flow coolant thermostat,removed my oil cooler and installed a heat exchanger.My temps start to rise almost immediately after startup and have both stabilised by the time I have reached the run up area.both temps stay together(92c) and apart from approximately a 5c variation,never very from a full power climb out to a 20 minute decent at less than half throttle.Also as part of the system I also have a "hot" block on both carbs at the opposite side of the throttle spindle area,no icing but an occasional attention getting misfire as the ice breaks away on occasions.I hope this may be of help to anyone flying in similar ,4 seasons in one day flying.

[atosrider]

more about the kiwi heat exchanger, please ... what market has the right size radiators, did you eliminate the under belly water radiator or the oil rad beside the gearbox ...

[atosrider]

I had 600 hours with the bypass oil thermostat on a 912uls, and always figured it was a waste of time .. it did not keep the oil hot enough more than half of the year, so I do not intend to purchase one for the 912ul rebuild I am currently into .... and I will check the ebay shutters idea, but if the kiwi solution gets rid of the underbelly rad, that will be first choice

[kmach]

Just buy the oil thermostat kit from Kitfox. It includes fittings, etc.

I have been using a Mocal oil thermostat since 2009 and a thermobob coolant thermostat since 2010.

I am curious of the make and model of the thermostats others have, it seems like most don't know the make of what they have, ?

[Dusty]

Unfortunatly the belly radiator has to stay and get plenty of airflow. It Has to get rid of of not only cylinder head heat but also oil/crankcase heat. The heat exchanger I used is one from the wine industry and has more than ample strength and flow(it is in the suction side of the pump,and the coolant pressure is only what the Rotax/BMW radiator cap will support) laminova do a better unit,but at a not so great price.

[WWhunter]

Not sure what to tell you other than I purchased it from Lockwood. There is nothing on the unit other than " hot, cold, PC, and Made in USA" That is all!! Google Lockwood and look at their parts catalog. I am guessing Lockwood has a subcontractor making them.

[HighWing]

Sort of felt of uncomfortable modifying the plumbing on the oil cooler system that served so well in my first Model IV, it was do the same on the new build. Controlled by a knob mounted near the throttle.

[WWhunter]

Lowell,
I decided not to install it at this time. I felt it was another point to be checked for leaks and additional weight. There's already enough crap under the cowl so why add more!!
I was actually thinking of getting a system like you show in your post. Where did you get that one?

[HighWing]

I made it. I had something similar on my first Model IV but with larger shutters.

[WWhunter]

Looks fairly easy to fabricate. What did you use for the rods? They tack welded to the shutters?

[HighWing]

I used the control rods available at RC airplane suppliers they come threaded one end and I bend to shape. The shutters are made with a curled edge on top and they are glued to the rods with a structural epoxy injected into the joint after final assembly then the rods are rotated to cover the entire rod shutter interface then positioned in the closed position for cure. I think I still have some tooling.

[WWhunter]

Thanks Lowell! I'll figure something else out. I'm guessing the nearest hoppy/RC place would be 200+ miles away from me. I live in the woods, literally!! 25+ miles to the nearest town (2400 pop.) I'll measure my cooler and maybe can just order some online. I'm fairly 'crafty' so I think I can figure something out.

[DHeal]

Here is a manufactured oil cooler shutter device that may be applicable for your use. Due to its "partial full-time air blockage", I would probably remove it for hot, summer flying and reinstall it for cold weather.

https://antisplataero.com/products/oil-cooler-air-shutter