RX7 turboII engines used a thermostat equipped oil cooler. I have mine tig welded at the mounting brackets to the end tanks on my FMIC. (Very little surface area actually touches between the two, and it's lined up perfectly so the upper grille air flow goes over the oil cooler and the lower grilled air flow goes over the FMIC. One of these days, I'm adding a air flow diverter design that will allow even better air flow through these, and keep the air flow seperated better.
The thermostat works. I took mine apart, and re-tapped the stock sized fittings which were AN8 to AN10. (The stock ID in and out on the cooler.)
Same with the oil pump. I've modifed and ported my oil pump to accept AN10 fittings. (You can get BSP 18mm 90 fittings to AN10, but the ID of the fitting is not giving you full flow.) Same goes for the stock fitting on the filter side of the block. You have to drill and tap the block for a larger 20mm BSP to AN10 fitting, to get full ID maintained from the pump to the exit point on the block.
To keep the AN10 sized theme, we tapped and plugged the small drilled out passage that normally feeds the stock filter boss on the engine block. The stock main galley thread is 20mm, so a BSP to AN10 fitting works great there, no mods required.
I use a 1/2" NPT compression thread on the outlet where the NA cooler bypass would bolt up to the block. (The GTE has a simple block off plate there stock.) If I did it again, I'd go 20 BSP to AN10 as the straight threads of the bsp fitting don't stress the block like the 1/2" NPT ones do.
I broke a block using the 1/2NPT thread fitting on the rail port. (SUCKED FOR SURE< had to tear down the entire motor, and re-machine the block for a BSP20 to AN10.. Note how low mine is compared to stock which is at the oil pan rail height.)
Shimmed the pump with a 10mm nut, and two washers. Also ported the pump to smooth flow out of the pump. No sharp edges on the corners between the pump gears and the exit point into the 90 BSP fitting.
I don't know why there should be a problem using stainless line inside the pan. It's pretty rugged stuff, and should hold up to the heat and oil just fine.
My system is AN10 from the pump to the return at the galley. I used Canton Mecca depth filter and 3 quart accusump. Also used a 1 quart Oil Guard bypass filter that takes oil out of the main galley, and filters it down to just one micron or better. (The Canton filters are claimed to be good down to 8 microns or better, and flow more dirty than a brand new paper pleated filter can.)
This gives you an idea of how convoluted the oil system can become if you let it take control of your engine build!
Small line is feed for turbo.
Two other small AN4 lines are oil supply from the main galley to the bypass filter, and the return line dumping oil back into the pan via the stock oil cooler dump port at the oil pan.
Then there is the AN10 line coming out of the engine, and the AN10 lines, one way valve, and T fitting allowing the accusump to fill/supply oil, and oil to go into the engine at the main galley. (Middle of the round filter boss on the engine is directly into the main galley that supplies oil to your entire engine, crank first.)
