I currently own three 1st gen rx-7s . I have started to swap two of the engines(81' gsl motor to an 84')
I have run into a few problems...

first the 81' has a radiator style oil cooler and the 84 has an oil to water cooler

The question is " Can I do away with the radiator system and use the oil to water cooler?"

second ,the 81' has a wiring harness on the passenger side of the motor and the 84' is on the drivers side

" Is the harness interchangeable , or do I need to buy a new harness?"

I have found that the haynes manual sucks , "Does anyone know a better rx-7 bible?"

finally (Can anyone think of any other modifications I may run into ?"

Thanks in advance,

 

moving to 1st gen section

 

if the 81 oil cooler is anything like the 79-80 style, then it is probably better than the 84. so i would keep that.

i would not interchange the wiring harnesses. right now i have an 80 engine harness on my engine, and a 79 engine bay harness, and there are a lot of problems. i would suggest against it.. the easiest way to get around that is to leave the engine bay harness in the body that you are going to use, and swap the engine harness to match.

 

Toss the oil to water cooler, it's a pile 'o' junk... keep the radiator style air-oil cooler..

 

I would go with the radiator style oil cooler...it's alot better than the water cooler.

 

AFAIK all 12A cars (not sure on 13B but probably them too) have the engine harness on the driver's (spark plug) side of the car. Hmm.

 

Thats not true 84-85 12a engine wiring harness are on the passenger side! just below the washer tank!. I put a 83 12a in my 85 and just used the 85 wiring harness. It will work.

 

Wow, strange. The engine I bought a few years ago was definitely an '84-85 (had water/oil cooler and 6 solenoids in a row on the rack - '83 had 5 in a row) yet the wiring definitely all went off to the left side of the engine bay.

I never really paid much attention to the wiring on the '85, but now you've got me curious!

 

Yeah i was suprised too, but it does go toward the drivers side then loops back to the passenger side in front of the carb.

 

Yeah my wiring goes through the pass side, well seems logical cause thats the side the ECU is on...

Oh and a side point of interest is theres a 6 or 8 point harness (i forget if its 8 or 6) on the pass side, that carries the oil temp sesor, the white/blk from the alt (goes to the choke and check relay). Also in this small harness is oil pressure from sender, a tach wire, and something else. But whats funny about it they come from the motor to the pass side, and then all the way back to the front and around the drivers side and then back in the drivers side gromet...

I have really studied this cause I wanted to make my Haltech install as pleasureable as possible

 

I've heard of people using both for added efficiency...but I'd just go with the air-oil cooler.