For those of you with oil temp gauges
 

1) where/how did you mount the sender ? eg did u use the mazdatrix/rb filter pedestal ? or did u fabricate your own into the pan ?

2) what normal operating temp to you read ? (in degree celcius please)

We just had a discussion about your first question here:
https://www.rx7club.com/1st-generation-specific-1979-1985-18/water-temp-oil-press-gauges-question-546977/

The oil in the pan is at a higher temperature than anywhere else because it just left the rotors after cooling them. Temperatures of 200°+ are not uncommon. I use a compost bin thermometer which has a really long probe and a range up to 220°F. It fits down into the pan and the guage part is up near the oil cap.

It's more productive to measure oil temperatures after it has flowed through the oil cooler, but before it enters the engine. The RB/Mazdatrix adaptor works well.

Mazdatrix used to sell a banjo bolt replacement with a threaded opening on the end of the bolt for the oil return line just under the pedestal. That's where I have mine mounted. Oil temps pretty much parallel my water temps in the summer under normal driving conditions. Winter months (Phoenix) I have to drive her a while just to get it up into the 160F + range. This is with an R1 (dual oil coolers).

Wouldn't the oil in the pan be after it's been cooled, if you have an oil cooler, as that is where the pickup is for the pump?

I have mine mounted in the pan... my temps in traffic are ~10* - 15* (F) higher than water temp. On the open road they're usually the same.

Cooled oil goes back to the engine at the rear iron, up to the filter, then through the bearings and rotors, which then falls into the pan for pickup through the pump, and out the front cover to the fmoc.

I would install a temp probe in the banjo bolt on the rear iron. It will not give the highest temp reading of the oil, but will tell you if the cooled oil going into the engine is too hot and the oil cooling system is maxed out.

so whats the minimum temp for oil????
 

I just installed 2 eunos cosmo oil coolers in my FB, and currently in 90~95 F ambient, the oil temp is reading 158 F

before the oil (105C) and water temps (95C ish and climbing while at the track) were sky high (in 80 F temp ambient) , but after I put in the Koyo copper FC radiator the water temps dropped , but not the oil.

So I then put in the two cosmo oil coolers that I had sitting around, and presto I suddenly was running oil temps in the 70C (158 F) range in 90 ambient at night when the temps drop it drops down to 140 F

is this too low? I have heard that it might be...

I currently run 20w50 oil.

kenn

I'm no expert but I would say it may be to low, it may be staying to thick at that temp. There is such a thing as "over cooling" an engine, but I don't know at what point that would be.

I think about it this way, the lowest t-stat they sale is a 160* so I would assume theres a reason for that (maybe there not really). I thiink two oil coolers may be a bit much. And especially for 20w/50.

How does your oil pressure look?

Its the same as prior to installing the oil coolers.

4 kilograms when cold at idle
2.4 kilograms warmed up at idle,
and 4.5 kilograms at 5000 rpm .8 kgs boost in 3rd gear.

kenn