Oil cooler cowl inlet

[Gripdana]

FWIW. I do not have a bottom vent on my top mounted oil cooler Aerovee. I think it forces more cooling air through the oil cooler and past the heads. I have not had any cooling issues with this set up.

[Sonerai13]

I have not completely closed off the bottom opening but others have with mixed results. Some have had adequate oil temps, others had high oil temps. I put the grill I made on last summer and the oil temps went up, that is only about a 50% reduction to the opening. I took it off and haven't put it back on. I may see what it does in cooler weather but not now with the oats going up(finally).

If you have the oil temp probe in the bottom of the sump (in place of the oil drain plug) it gets cooled by the air coming through that lower opening. Closing off the lower opening doesn't really change the oil temperature in the engine. It just changes the temp that the probe is reporting. Yes, cooling the probe itself will change the temp readout. So you can expect to have higher indicated oil temp with the lower opening closed off. But that doesn't really mean that the engine is running that much hotter.

If you move the oil temp probe to the location we use on the turbo engines, you'll find that the temp doesn't change that much by opening or closing the lower cowl opening. It may change a little, but it won't be drastic.

As a side note on the "probe-cooling" issue, take a look at Piper Super Cubs and other Piper aircraft of that era. People complained about high oil temps on the early Super Cubs and other similar models, so Piper started installing a blast tube the blew cold air directly on the probe. They didn't change anything else, but they quit getting complaints of high oil temp!

[Darick]

Joe, you said,

If you move the oil temp probe to the location we use on the turbo engines, you'll find that the temp doesn't change that much by opening or closing the lower cowl opening.

Where is that location? And is it recommended for the normally aspirated aerovee?

[MichaelFarley56]

I believe Joe is talking about the oil temperature sender plate found on the front face of the engine block, next to the oil pump. If you install the temp probe there, that will be above the lower cooler shroud and thus not in the direct airflow.

Any AeroVee builder can use that location, and the non-turbo people will have to if they use the extended sump.

[Sonerai13]

Mike is correct. Most VW engine cases have a block-off plate on the front face of the oil sump (front of an airplane engine that is, near the oil pump) that can be drilled and tapped to accept the oil temp probe. It is discussed on page 11 of the AeroVee Turbo Retrofit Manual, which you can download here:

http://www.aeroconversions.com/support/ ... Manual.pdf