Light Aircraft Association

I have a VW 1834 engine fitted in a Colibri which runs well but has had an oil cooler fitted underneath the fuselage which a) spoils the lines of the aircraft and b) must knock a few knots off the cruise. Originally the aircraft flew for several years without one fitted so I assume the oil temps were within limits. The previous owner said it was fitted as the oil temp was high but thought the temp sensor was installed in the wrong place. I'm not sure where it was fitted but now the sensor is in the sump plate.

I have had a similar sized engine in a Nipper without an oil cooler and not suffered a problem and also a 1600cc in a Turbulent that cooled it's oil around the manifold, plus also warmed the carb.

Any comments regarding my plan to remove it would be welcomed. Do fellow VW owners have oil coolers fitted or not.

Regards

Mark

Perhaps stage 1 is to blank off the cooler and see if it is actually making a difference to the oil temperature...

Nick's suggestion seems sensible: get the duct tape out!

With oil cooling, and engine cooling generally, I would guess that a heck of a lot depends on the cowlings, both in the design philosophy of them and the implementation.
By design philosophy, are they close fitting pressure cowlings like RVs, 'hang the cylinders out in the breeze' of Piper cubs, or something in between?

Just one point of reference, when the VW is in a Beetle, van etc it has an oil cooler fitted, mounted on top of the cases. Admittedly they are in a 'closely cowled' environment at the back of the vehicle, but they do have a dedicated cooling fan too.

Our VP1 has a cooler, but it is within the cowlings.
Hanging it underneath like a barn door in the airflow does sound a bit inelegant as a solution.

Hi

I have no oil cooler on my vw 1600 engined mono. My oil temperature sender is located in the sump as well. I also have a pressure cowling and have never experienced high oil temperatures.

Regards

Gary

Gary,
does that mean that the mono's engine has a bypass arrangement on top of the cases where the oil cooler / take-off normally sits?

If so any idea where to get one from?

Or does this feed off to an oil filter instead?

Just considering options for the VP1.
We are seriously considering ditching the external oil filter arrangement once the engine is run in as it's not light, and changing the oil and cleaning the sump screen every 25 hours isn't that expensive / onerous. Sounds like the cooler could go too, and save even more!
I just put it all back when I rebuilt and electronically ignited the 1853 as I assumed at the time it needed it all.

The sump itself is quite a good heat exchanger. Nice sized duct under the prop, ally baffle to duct the air past the corrugations and then a larger outlet near the back of the cowling in the low pressure area.
Losing the cooler and filter will reduce the quantity of oil in the system and you'll find higher oil temps unless you add a larger sump so a filter canister is actually one of the lightest ways of containing a larger quantity of oil in the engine.
Not painting the sump and heads is also a good way of promoting heat exchange into the airflow.

Whilst I think abaout it, most filters use a 3/4 BSP (I hope I remembered correctly) thread on the mounting. Reliant Robin filters are the smallest ones I could find and Landrover Discovery filters were the largest capacity at almost 1 litre.

Hi I used to have trouble getting enough heat in the oil in the Luton Minor with no oil cooler! Was always just on the lower end of acceptable!! 1600 peacock convertion!

Hello,
The 1835 cc engine in my VP-1 has no oil cooler, yet the oil temperature is always lower than optimum. I winter it struggles to get up to 50 deg C and in summer perhaps 60 C. There is also evidence of moisture condensation and emulsion forming on the inside of the oil filler cap. It must be pretty draughty under the sump and that seems to provide all the cooling necessary. A more enclosed cowling might require a cooler?

Noel.

Hello,
The 1835 cc engine in my VP-1 has no oil cooler, yet the oil temperature is always lower than optimum. In winter it struggles to get up to 50 deg C and in summer perhaps 60 C. There is also evidence of moisture condensation and emulsion forming on the inside of the oil filler cap. It must be pretty draughty under the sump and that seems to provide all the cooling necessary. A more enclosed cowling might require a cooler though?

Noel.

Hi Mark

Yes, I do have a spin-on oil filter arrangement with a bypass arrangement as you suggest. My pick-off plate is home-made, although I think Great Plains in the US do sell one to fit a VW. However, it may not fit every engine, as the manifold could get in the way.

Several people have told me that having a spin on oil filter set up is a good thing. Easy to replace, and easy to check for unwanted bits inside it.

Cheers

Gary

Hi Noel

Snap! And I have a pressure cowl.

Cheers

Gary