Having had the pleasure of good runs this week in the Libra - thoughts again turned to the benefits of an oil cooler.
Oil gets noticeably warm and pressure drops with a good 100+ mile run on A roads through the Yorkshire Dales and the M6 up to Scotland - especially on Tuesday this week!!!
Any views on the best location/type/benefits????

I tried a 13 row air to oil cooler with an electric fan added. Positioned in the engine bay it didn't get good airflow even with the fan so I think it may have actually been an oil warmer!

I then went for a Laminova which I fitted in the radiator return hose where it runs vertically behind the bulkhead and routed the oil pipes from a sandwich plate on the filter boss. It is a much tidier install than the air radiator and it seems to work. Having said that I've never been able to get my oil temperature gauge to work with the 160 engine - it is a combined four wire sender with 2 wires going to the ECU and the other 2 wires must be for the gauge but they just won't work so I don't know the precise impact on the oil temperature!

However, although the oil pressure still drops a bit when the oil is hot it is not as much as it used to without the laminova so I'm taking that to mean the oil isn't now overheating (even on a track day). The additional load on the water cooling doesn't seem to have had any noticeable impact.

The big downside is they aren't cheap but if you look for long enough they do come up on ebay. The one I got had never been installed but was less than half the new price. The shortest one seems fine, with 32mm coolant bosses and dash 10 oil hose connections.

What kind of oil temperature are you seeing? I've connected an OBD gauge and my dashboard gauge takes quite some time to build up and when it does it's about 10 degrees out.
I thought my V6 took about 8-10 miles to warm up but in actual fact, it's about 3 by which time the water and oil are around 90 degrees. The V6 has a water cooled oil cooler and oil stays at 90 and coolant varies between 90-95 even on hot days. I think some of the later K series ECU's (Mems3) are OBD2. If yours is, you could check the accuracy of your gauges.

Oil/water heat exchanger in a sandwich plate under the oil filter can be very effective. Doesn't require any airflow. Has the added advantage of quicker warmup of the oil.

Standard equipment on many Toyotas and other OE engines. My 2ZZ-GE has one of these: . . . . https://www.google.com.au/imgres?imgurl=https://i.imgur.com/ZVua3oHl.jpg&imgrefurl=https://www.lotustalk.com/threads/use-factory-oil-coolers-for-air-to-water-heat-exchanger-on-street-car.89922/&h=640&w=480&tbnid=ajSfjKumho7ZkM&q=toyota+water+oil+cooler&tbnh=137&tbnw=103&usg=AI4_-kQh-ierwDaIZPQpKm9oX7v0WiN5HA&vet=1&docid=R08TVNszS-HFyM&hl=en-AU&sa=X&ved=2ahUKEwjYqKrWv8jxAhWMfn0KHWkwCrAQ9QEwBHoECAoQDA#spf=1625370161663

Ford cooler adapted to Toyota engine . . . . https://www.locostbuilders.co.uk/forum/9/viewthread.php?tid=59219

On my Coupe I used a Laminove oil/water intercooler.

https://www.merlinmotorsport.co.uk/s/oi ... -exchanger

Very compact and no need for any cooling airflow.

If you have a K series engine why not us the water/oil cooler from the MG TF VVC?

Failing that the Laminova ones work really well and is what I used.

https://www.mg-rover.org/threads/oil-cooling.253761/

I tried - the 160 engine I got came from a TF so had the OEM cooler. Unfortunately the OEM pipes were perished and seeping and the fittings into the filter boss were already rounded off. Tried undoing them with vice grips and managed to break the filter boss casting then found out the ones with the oil cooler take offs are like rocking horse poo so instead used the sandwich plate I already had from the 143 engine/air/oil cooler experiment and by then had decided the OEM oil/ water bath cooler doesn't do very much as the surface area of oil to water for heat exchange is around a quarter of the smallest laminova!

Thanks all - Laminova it is