how to measure 915 gearbox oil temperature

[sopor]

I have a 915 gearbox in my 3.0 914/6 conversion and am trying to figure out how to check the gearbox oil temp. As the box is behind the engine and the heat exchangers run along both sides it sits in a fairly hot space also heated by the engine. When the box gets hot shifting seems to degrade so would like to understand if high oil temperatures might be part of the problem. Short of getting the car good and hot after a spirited drive and dumping the oil and check its temperature any other thoughts? I’ve searched on here and Pelican and found nothing relevant.

Edited September 30, 2023 by sopor

[Ian Comerford]

No idea on how to check the temp but two things spring to mind, first, have you tried a different oil?  Second, have you asked on ddk, there are a few 914 owners on there as we well as a few who race so they may have an idea.

[sopor]

Thanks for your post. I’m running the Motul oil that seems well recommended on the 915. Will have a look at DDK to see what I can learn.

[Northy]

Very crude and inaccurate method but you could try using an infrared thermometer on the case to give a broad indication of temp change? Failing that, could you plumb in a temp sensor to where the cooler take-offs go? 

 

[Henry]

I found having a sensor and gauge on my 3.6 915 combo , oil temp not to be a concern at normal  60 mph ish  speeds despite very spirited driving it does start to rise though on sustained high speed in 5th say around 100mph . May not be relevant as may be getting cooked by your exhaust setup . I would try as Lewis suggested with a  infrared thermometer .