TOPIC:

My question is: What is the desired oil temperature on a 1000J motor?  In my 1000j motor in a small race car I would like to install an oil thermostat  for the oil cooler.  The only full flow(ie zero pressure drop) I have found is by Improved Racing They are available with activation  temperatures from 145F to 215F with 20 degree increments.  With the roller  rather than plain bearings what is the preferred operating oil temperature. 

I've got no idea what the actual temp is but J motors were notorious for cooking the center two cylinders.
An oil cooler is essential especially if in warmer climes. 

Around 180 - 190f is reckoned to be the temp required to burn of contaminants in the oil and still provide the required lubrication

You said in your intro thread the car weighs in at 840 pounds  
Twice what  a bike is .  How is the airflow over the motor ? 
Asking to try and factor the added strain on the motor which will add to  your heat  potential problem 
I would  probably run the system with no thermostat  , or one set at the lowest temp. 
Being a race car I'm sure the motor will be run hard so my concern is keeping it cool, not warming it up
Just my 2cts
Dave

If you are going to race the car, that engine is going to run super hot.  Do you have an electric fan to blow on it?  

Wookie58 all my motorcycles 2 x FJ1200's, GPZ1100 and Z1R run at 80 C to 90 C (around 180 to around 190). P.S The GPZ1100 has a FJ1200 oil cooler. All these bikes can get to 100 C but that in is Australia with up to 40 C + outside.

I believe Harleys run up to 140 C+ (correct me if I'm wrong, remember I'm talking about Australia temps), I think that's close to a max good working temp. 

My friend has a Z900 (Z1260) he has a huge oil cooler which runs around 60 to 70 C but I don't believe that is good as oil should reach a working  temp .

You want a thermostat that opens at 180 degrees.

Thanks for the the confirmation of the oil temperature below 200F.  My research on roller bearing indicates the same, SKF would like the roller bearing housings to be under 100  C to be safe in the long term. And, the cylinder head and cams can use all the flow and cooling they can get.

For cooling there are 2 ea 12:"extractor fans above the motor, and 2 12" supply fans mounted in the chassis. None are ideally located and  due to the body style which is not modern era aero the supply fans will eventually get relocated a bit.  The oil cooler also has a fan and I have relocated it a bit to improve the airflow..  The cooler is a tube style with 1/2" tubes rather than plate and frame so not quite as efficient but a lower pressure drop.  I am increasing the line size from -6 (3/8" nom.) to -8 (1/2" nom.) to improve the flow..  I'm also adding a cylinder head temperature gauge.    I have replaced the exhaust cam and cam bearing due to previous heat problems, so I'm trying to fix it properly. 

The net cost of adding a full flow thermostat is about $300 and an in flow temperature switch to turn on the oil cooler fan is also available.  I don't know what the output of the alternator is but I suspect that I may well have to recharge my smallish car battery between races, a lithium battey is probably the e the best answer for this.. 

There are several modern classes of MC powered cars, but most are running more modern water cooled motors.  This is the type of thing we get into working with vintage racing.  The first MC motor this car had was the old 750 Suzuki 2 stroke "water buffalo".

Below is spec for 81-83 "J" charging system. If you go for a lithium battery make sure you use a MOSFET reg/rec with a stable output (I would also recommend a 30a fuse in the reg/rec output to the battery to avoid possible "thermal runaway's" FIRE)

 

I can't imagine the oil temp ever being below 180F, except for when warming up the engine.  I'd skip the $300 thermostat.