I am an rx7 lover mostly the 1st gens a few 2nds and alot of 3rds but i am possed with a promblem. My 82 rx had a really bad raditor leak and so i thought simple just get a knew one. Yeah was fooled, i got one alright but it was to long and leaves no room for the oil cooler i have a few friends that have rx7s and they say the hell with it just cut it off and run the lines straight my question is: Do i really need the oil cooler or does the engene temp stay low enough. Any info you can give will be a great help


Thanks bv82rx7

 

yeah you do need a oil cooler, my understanding was 2/3 of the engine heat went out through the oil and 1/3 through coolant. it sounds like you got the 84+ taller radiator go exchange it for the right one if you still can or make longer lines for the oil cooler...

 

That would be a 83 up radiator...

You need the smaller version..

 

You can order one from www.radiators.com for under $130.

 

You need a good oil cooler or you WILL roach your engine real quickly. Passion is correct, but his numbers are backwards. 2/3 coolant, 1/3 oil cooler.

 

Rotary morots love to cook the oil!! I wouldent try running it without an oil cooler for more than a few minutes.

 

rx7passion has it right ... you lose 2/3 of your heat through the oil. if you don't believe me, look it up ...

bv82rx7~
if you can't exchange the radiator for the right model, then just get some decent lines made and mount the oil cooler in front of the radiator. i think it's a better setup that way anyways.

BTW ... ditch your friends that told you go without the oil cooler! they're morons! when they blow up their cars, let me know ... i may want to get a body for a racecar.

 

Yep 2/3 through oil.

 

I did look it up.

Quoted from my 1985 Racing Bleat catalog:
"Obviously the size and location of the oil cooler are important. Remember that roughly one-third of all the heat rejected in the cooling system (water and oil) goes out through the oil cooler. Therefore the oil cooler should get about one-third of the total air". -WG.

 

Thank you WG. You my Hero!

 

Your friends obviously must not know how a rotary engine is structured.

Look at a picture of one, or find one that's had the front cover removed. You'll notice a large open area in the middle of the rotor, where the eccentric shaft goes... That's full of oil when the engine is together...

Go one step further and cut a rotor in half. It's hollow inside, save for fins and internal ribbing and such. It's full of oil when the engine is together too...

All this is for lubrication AND cooling. On a boinger, the combustion chamber is a cylinder, surrounded on the sides with coolant. The area below the piston and above the valves has oil in it...

On a rotary, Only the outer housings of the engine contain coolant passages. So there's a lot less area of the conbustion chamber loosing heat through the coolant... Hence the added heat on the oil.

You'll notice on boingers that are set up to be run hard, they have oil coolers too.