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EA81 Oil Cooler?


rotor

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Test flying a fuel injected ea81 running electronic ignition in my Jodel D18 and my oil temp today reached 260 Deg F on climb out. Water was only around the 190 Deg F mark. Engine did 5600 rpm with a 2.1:1 reduction box and 14 degrees on a 70inch warp drive prop. Flew beautifully except for the oil temp that didnt seem to want to come down after climbing to 1500 ft.

 

I've got a nice little oil cooler off a 3300 Jabiru engine but I haven't got a clue on where the best place is for pickup and return lines from the motor?

 

Any help here would be greatly appreciated.

 

Geoff

 

 

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Test flying a fuel injected ea81 running electronic ignition in my Jodel D18 and my oil temp today reached 260 Deg F on climb out. Water was only around the 190 Deg F mark. Engine did 5600 rpm with a 2.1:1 reduction box and 14 degrees on a 70inch warp drive prop. Flew beautifully except for the oil temp that didnt seem to want to come down after climbing to 1500 ft.I've got a nice little oil cooler off a 3300 Jabiru engine but I haven't got a clue on where the best place is for pickup and return lines from the motor?

Any help here would be greatly appreciated.

 

Geoff

I once fitted an oil cooler - sandwich adaptor - to a 3K Corolla; I used a car air conditioner evaporator as the heat exchanger. The oil was still golden after 12,000km. Most oil coolers are way too small!

 

 

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Geoff, as a long-time EA81 driver, I am concerned that 5,600 rpm sounds rather high even for an injected version. My experience is that oil temp. increases in almost direct proportion to revs while coolant temp. is no problem. I found that increasing prop pitch and running with a wider open throttle increased economy and kept oil temps reasonable. I have never fitted an oil cooler, just a duct to provide ram air over the original sump. On WOT climb on a hot day I see up to 120C which then comes down to 105 in cruise. I run a Bolly 3 blade 72 x 60 at 4300 rpm cruise on a single carby engine. Reduction is 2.25 to 1. As an experiment some years ago, I fitted an oil temp sender to the sump plug on our EJ25 in a Subaru Outback and was surprised to see 125C at 110kph on a 35C day while driving to Adelaide. These temps are considered normal in car engines working nowhere near as hard as we run them. A call to Castrol's tech people confirmed that they are happy for semi-synthetic oils to run continuously at 125C. Brief excursions higher call for more frequent oil changes.

 

I offer the above as food for thought, not as any prescription for your installation.

 

 

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Geoff, as a long-time EA81 driver, I am concerned that 5,600 rpm sounds rather high even for an injected version. My experience is that oil temp. increases in almost direct proportion to revs while coolant temp. is no problem. I found that increasing prop pitch and running with a wider open throttle increased economy and kept oil temps reasonable. I have never fitted an oil cooler, just a duct to provide ram air over the original sump. On WOT climb on a hot day I see up to 120C which then comes down to 105 in cruise. I run a Bolly 3 blade 72 x 60 at 4300 rpm cruise on a single carby engine. Reduction is 2.25 to 1. As an experiment some years ago, I fitted an oil temp sender to the sump plug on our EJ25 in a Subaru Outback and was surprised to see 125C at 110kph on a 35C day while driving to Adelaide. These temps are considered normal in car engines working nowhere near as hard as we run them. A call to Castrol's tech people confirmed that they are happy for semi-synthetic oils to run continuously at 125C. Brief excursions higher call for more frequent oil changes.I offer the above as food for thought, not as any prescription for your installation.

A shell engineer I chanced upon, said that oils start to crack at ~86C, and the rate of cracking doubles with every 2 deg increase. As sulphuric acid starts to evaporate at 82C, running your oil at between 85C and 86C should give a very long lubricant life; and provided each run lasts long enough to get all the oil up to temp and boil off the acid, it'll give your engine a very long life. As the cracking temp is a function of the carbon-carbon bonds, I don't see how a synthetic oil would have any difference, unless it contained silicone oil(s)... which it may well.

There is an awful lot of engineering tradition about an engine's friction losses due to cold oil; and it's valid for Thomas the Tank Engine. Keeping the oil cool in the Corolla marginally improved fuel consuption, and eliminated the need to adjust the valve lash.

 

 

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Oil companies, if you can get to their experts, usually seem to credit 120 degrees or so as not doing engine damage with synthetics. I think they consider this as CAN DO (but don't do it always). You have to hit about 90 to get all the water out of the oil, as it is what the bad stuff builds up in. This depends where you measure it. You sure won't be measuring the hottest part of the engine which will be the exhaust valve guide and the piston crown where you will often find the gudgeon pin shows blue or dark straw and it's the steel part that registers the colours.

 

There's not much oil in a Jabiru but a lot of oil in itself won't make the temp cooler It will just make it take longer to get there as the oil is a heat soak, like the mass of the engine itself.

 

It is good if your engine will run without an oil cooler because it is simpler and therefore safer. Earlier engines running babbit lined shells have less friction.. Most of the later stuff uses Alutin (Used to be copper-lead with an indium overlay) which has a higher coefficient of friction and needs more oil flow to cool it. Nev

 

 

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Geoff, as a long-time EA81 driver, I am concerned that 5,600 rpm sounds rather high even for an injected version. My experience is that oil temp. increases in almost direct proportion to revs while coolant temp. is no problem. I found that increasing prop pitch and running with a wider open throttle increased economy and kept oil temps reasonable. I have never fitted an oil cooler, just a duct to provide ram air over the original sump. On WOT climb on a hot day I see up to 120C which then comes down to 105 in cruise. I run a Bolly 3 blade 72 x 60 at 4300 rpm cruise on a single carby engine. Reduction is 2.25 to 1. As an experiment some years ago, I fitted an oil temp sender to the sump plug on our EJ25 in a Subaru Outback and was surprised to see 125C at 110kph on a 35C day while driving to Adelaide. These temps are considered normal in car engines working nowhere near as hard as we run them. A call to Castrol's tech people confirmed that they are happy for semi-synthetic oils to run continuously at 125C. Brief excursions higher call for more frequent oil changes.I offer the above as food for thought, not as any prescription for your installation.

Yes I agree that 5600 rpm is a little to high. ASI indicated 60 knots on climb out - a little too slow and steep I think. The pilot said that he lowered the nose at around 1,000 ft but I think he should have dropped the revs after getting in the air adjusting to maybe 5,000 for the climb and climbed out at 70/75 knots. By the time he reached 1500 ft it had reached 265 F and didn't want to come back down on the downwind leg - 4000 rpm / 85 knots.

 

A courser prop would help to lower the revs and decrease the climb angle a bit - he was at 1000ft at the end of the Gladstone strip which is about 6000 ft long. Not sure how much courser a 3 bladed Warp Drive can go to and remain efficient - its through a 2.1:1 box and has 14.5 degrees at the tips now.

 

Ive got a universal sandwich adapter coming and will try and get it test flown again in the next couple of days.

 

 

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Hi Rotor, would you mind sharing with us where you ordered the adapter from.Cheers

 

JimG

Sorry Jim, missed your post

 

Haven't found a local auto shop that has them in stock but am going to try a local place which I overlooked "Gladstone Air Filters" tomorrow as I'm a little doubtful the one I ordered will get here as quick as they said it would. If they've got one I'll just keep the other for my spare ea81 (currently turbo'd and in need of a rebuild)

 

Ebay has a few different shops that sell them - here's a couple of places - the first is where I bought it.

 

http://www.ebay.com.au/itm/321316434586?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

 

http://www.ebay.com.au/itm/BB-0011-UNIVERSAL-POLISHED-OIL-SANDWICH-PLATE-COOLER-ADAPTER-KIT-/221305868708?pt=AU_Car_Parts_Accessories&hash=item3386db91a4

 

Just do a search for universal cooler adapter on google.

 

 

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