Jabiru oil thermostat

[Paul davenport]

Has any one flying jabiru aircraft or jabiru powered aircraft fitted an oil thermostat and apart from a faster warm up and stable oil temperature, have there been any other noticeable. Did Using larger hoses to and from the oil cooler lower your temperatures during the summer hot weather

[440032]

Of three same 2200 powered aircraft at my airfield:

Mine - no oil thermostat. The other two have THERMOSTASIS. (are they still available - I dunno)

One has the original and standard 5/16 oil hoses for our serial engines. I'm not exactly sure if the other has too, or if he went up to 3/8 hoses with a recent cooler change.

I run a cooler blanking plate in winter to get usable oil temp, the other two do not. My winter oil temp is about 90C, and the others are closer to 80C which is in the factory spec green range. A bit more might be nicer.

Zero problems with the other two, summer or winter. Zero problems with mine too by the way.

On the earlier 2200 engines, Thermostatis required the use of a lower profile oil filter. Ryco would no longer fit. Early Valvoline V05 did fit, later ones did not. That was a WHAT THE.... moment to solve.

Can't recall what brand oil filter they currently use - it's something a little exotic that took a bit of finding.

 

[Paul davenport]

I have the Thermostasis and will fit it to my 230 . Is it worth going up to the larger hose, to me it makes sense to go larger hose, I am hoping it will keep the oil temp lower on really hot days hence the question

[skippydiesel]

Oil thermostat will do absolutely nothing for high ambient or engine temperatures.

[Paul davenport]

I am well aware that the thermostat controls the minimum temperature and the heat exchanger efficiency controls the maximum .  So the question still stands do any Jab drivers have the experience to answer the questions 

[Blueadventures]

1 hour ago, Paul davenport said:

I have the Thermostasis and will fit it to my 230 . Is it worth going up to the larger hose, to me it makes sense to go larger hose, I am hoping it will keep the oil temp lower on really hot days hence the question

You will only get the removal of heat if you include a larger or additional oil cooler.  The thermostat will maintain the warmup to operating temp.  I believe.

[Paul davenport]

Will the larger internal dia of the hoses allow better oil flow more heat loss?

[Blueadventures]

21 minutes ago, Paul davenport said:

Will the larger internal dia of the hoses allow better oil flow more heat loss?

I cannot say specifically, but sometimes in marine Diesel engine heat exchangers I have had to restrict (reduce) the flow rate to improve the cooling as it allowed better heat transfer due to the slower flow.

[Paul davenport]

In the auto trade that would be the thermostat . In the jabs system the barbed hose fittings are far smaller than the oil cooler in and outlets. My reasoning is If the capacity of the pump has a higher flow than the hose allows ,restricting the oil flow through the oil cooler and causing a oil dump via the relief valve (in effect this dumped oil is not being cooled) would this raise temps on those hot days climbing. Fitting a thermostat which allows the fitting of larger hoses with larger flow may make the cooling system more efficient ? 

[skippydiesel]

In a piped/enclosed liquid transfer system, with a fixed delivery (pump), the "flow rate"  will ultimately be controlled by the diameter of the narrowest pipe (this might be the radiator if transmission cooling style). Other factors will be internal surface friction "pinch points" (some valves) etc.

 

Larger diameter delivery/return pipes to the oil radiator are unlikely to do anything very much unless the original pipes restricted the flow below optimum cooling capacity of the radiator.

[onetrack]

The speed of circulation through a cooler or radiator, of the liquid being cooled, is critical. If the hot liquid passes through the cooler or radiator too rapidly, the cooling effect is inadequate, as the hot liquid doesn't have enough time exposed to the air flow through the cooler or radiator, to release the heat it's carrying. The seemingly too-small diameter piping may be the engineers method of restricting the flow rate, to ensure maximum cooling effect.

 

Edited July 21, 2021 by onetrack

[facthunter]

ALL oil pumps on engine lube systems are close enough to positive displacement. As RPM's increase FLOW will until the pressure release valve limit's it or when at low rpm and high temp. the pressure drops for obvious reasons. ( thin oil and low flow rate). Oil rarely flows evenly through a core of a cooler. It will take the easiest path and that section  will be the hottest and other parts may not be getting much use at all if it's not designed properly. (or cleaned ). Nev

[IBob]

A recent incident here in NZ involved an automotive oil thermostat on a 912, which reportedly failed and cut off oil flow to the engine.  Fortunately, this happened on startup on the ground and the engine was promptly stopped.

If I were considering an oil thermostat, I would be sourcing one that cannot fail in this fashion: as I recall, there is one advertised for the 912, and the manufacturer specifically states it cannot cut off the oil flow if it fails.

[skippydiesel]

Good point IBob and adding to that is the addition of two additional points of potential hose failure plus a small weight penalty, all for cold weather operations that could possibly be accommodate by a temporary cowl flap or a bit of tape over part of the oil cooler.

[Paul davenport]

Sorry gentle men we seem to have drifted away again. It’s Jabiru we are talking about and my original question was to Jabiru engine powered aircraft. I appreciate your well intended comments, I have had one person reply with direct comparisons of Jabiru’s with and without thermostats (thermostasis brand) and I thank him for his input .

Jabiru specific actual information or real observations only please

[RFguy]

Paul

at OAT of 9C, at sustanied level flying at 25lph ish, I have a temp rise of 49 deg C. IE 58C

Not enough ! I have been experimenting with gradually more air damming in front of the cooler.

for warm up, I 100% block it, but it only gets to about 60 deg C at OAT = 10C. even after cylinders have got to 120s...

[skippydiesel]

33 minutes ago, Paul davenport said:

Sorry gentle men we seem to have drifted away again. It’s Jabiru we are talking about and my original question was to Jabiru engine powered aircraft. I appreciate your well intended comments, I have had one person reply with direct comparisons of Jabiru’s with and without thermostats (thermostasis brand) and I thank him for his input .

Jabiru specific actual information or real observations only please

Paul - while I have some sympathy for your Jab only responses,  I hope you understand, that the practical application of mechanical know how/physics is universal ie not limited to one aircraft brand or even just aircraft.

[Paul davenport]

Yes point taken but when you want specific model type info it clutters the conversation 

[440032]

Further note, my Jabiru 2200 has 5/16 oil hoses, barbs and the same on the Jabiru supplied cooler.

I've flown on a 44C day one time, chasing a yak52 around - didn't know it was that hot. No problemo.

[Phil Farnell]

Great range of replies guys to an oil temp problem. My J160C has just had a Gen 4 2200 cc motor installed and we have high engine oil temperatures!

We are now seeking help from Jabiru Engineers as to how this could be occuring with a new install. We've now conducted 3 circuits only to test run the engine, each time exceeding 100+ degrees before shutting down the engine. Our engine temp probes have been calibrated, all baffles installed as per Jabiru install requirements, and an additional heat shield installed between the exhaust and the oil cooler. Still runs very hot oil temperatures!

Help?

[skippydiesel]

In a correctly functioning oil cooling system, I would expect the oil to get over 100C in climb out (high power /load situation).

Dont know what the Jab operating instructions are, however I have always understood that in all engines, it is desirable for the crankcase oil to go over 100C, for an extended period (say 20-45 minutes)  specifically to drive of volatile contaminants (water/fuel/byproducts of combustion) in the oil. Further, modern oils are usually able to tolerate temperature to around 130C (not saying this is desirable).

If the cooling system is working correctly the high oil temperature will return/cool to below 100C, in cruise

If you are doing circuits, it may be that the short down wind/cruise leg, after the high power/load of climb out, is not long enough to see the temperature fall below 100C

I suggest taking the aircraft out of the circuit (stay within gliding distance/altitude) reduce power to cruise and observe the effect on the oil temperature. Oil gains heats & loses heat relativly slowly (compared with coolant/egt/cylinder barrels/heads)  so don't be in too much of a hurry.

Personally I like to see a the oil temperature at a constant 90-98C in crusie (temps may vary with OAT)

Edited April 15 by skippydiesel

[facthunter]

It might be better to see why it's hot. The Motor is new isn't it? Check the gauge. Is the motor tight at all.? Climb at a faster speed. When  the engine is shut down does it bounce off compression as it stops.. Does it have Blowby?  Nev