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I’ve had my ‘84 rx7 project for quite sometime. The engine is very strong, I’ve deleted the emissions and threw a weber on, and a racing beat header with custom exhaust. I’ve always liked the look of SA’s and the underside of my FB is a little more rotten then I feel is worth trying to repair. Long story somewhat shorter, I bought a 1980 SA with what seems like coolant seal issues but an extremely solid body and frame. And I’d like to swap my 12a from my FB into this chassis. I’m pretty confident in the swap, as I know most of it is quite straight forward. But I’ve noticed the main harnesses are a fair bit different along with a few other small details.. anything in particular I should look out for? Like hooking up coolant and oil temp wires and such to the SA chassis with the fb 12a? Is the beehive oil cooler less of a headache then keeping the external cooler from the SA? All tips are appreciated!
Last edited by Norlando; Apr 20, 2023 at 08:44 AM.
Reason: Sa is an ‘80
The front mounted oil cooler is regarded as better than the beehive at cooling the oil. The transmission from the 84 will place the shift level a couple inches further back, so it doesn't fit the plastic surround in the interior. Guys have overcome this by mixing and matching tranny bits to bring the lever location back to where it needs to be. Easier than creating new interior parts as the 84 plastic doesn't mesh with the SA.
Can't use the 1984 engine harness in the 1979. The 1979 doesn't have a computer. The 1979 does not not have an oil gauge. Also, the 1979 uses point sand the 1984 is an electric dizzy. You can swap in the electric dizzy but will need to use the 1984 dizzy harness and do a little wiring. On the 1984 rear iron, there is a Tee to supply water to the beehive oil cooler. You can cap that part of the T and go with the 1979 front mount oil cooler like Banzai indicates. You'll also want to use the 1979 radiator heater metal water line the runs on the passenger side. This will eliminate the need for the very expensive coolant line that runs to the beehive.
The front mounted oil cooler is regarded as better than the beehive at cooling the oil. The transmission from the 84 will place the shift level a couple inches further back, so it doesn't fit the plastic surround in the interior. Guys have overcome this by mixing and matching tranny bits to bring the lever location back to where it needs to be. Easier than creating new interior parts as the 84 plastic doesn't mesh with the SA.
Can I leave the SA’s trans in place and bolt the FB engine right up to it?
Can't use the 1984 engine harness in the 1979. The 1979 doesn't have a computer. The 1979 does not not have an oil gauge. Also, the 1979 uses point sand the 1984 is an electric dizzy. You can swap in the electric dizzy but will need to use the 1984 dizzy harness and do a little wiring. On the 1984 rear iron, there is a Tee to supply water to the beehive oil cooler. You can cap that part of the T and go with the 1979 front mount oil cooler like Banzai indicates. You'll also want to use the 1979 radiator heater metal water line the runs on the passenger side. This will eliminate the need for the very expensive coolant line that runs to the beehive.
Will my SA being an ‘80 make any difference in regards to that?
Regarding the ignition system, 1980 had electronic ignition with igniters mounted on the fender. The 1980 igniters will not work with the 1984 distributor, as the reluctors are different, so make sure you use the 81-85 igniters with 81-85 distributor, or 80 igniters with 80 distributor. No mixing and matching. I think most regard the 81-85 ignition system as better, so it might be best to wire that in.
Will my SA being an ‘80 make any difference in regards to that?
The 1984 engine will be fine. It's your choice to use any of the things I've mentioned. Best to stick with the 1979 oil cooler. The electric dizzy would be an upgrade worth doing since you have everything. if using the 1979 oil cooler, you'll need to stick with the 1979 radiator. if using the beehive, put in the 1984 radiator.
Can I leave the SA’s trans in place and bolt the FB engine right up to it?
You can but you MUST use the 1984 flywheel/clutch. The reason for this is that the flywheel must match the engine range (1983-1985) because of the balance of the rotating assembly.
You can but you MUST use the 1984 flywheel/clutch. The reason for this is that the flywheel must match the engine range (1983-1985) because of the balance of the rotating assembly.
Getting close to pulling the 1st engine out.. went through and marked everything I’ll need for the next motor with painters tape just to remind myself what goes where.. wrote on the tape with marker for the not so obvious connections. Pulled the RAD and the non functional A/C. As well as the cold start set up. Going to get the rad cleaned up and redone at a local shop, and going to use the external oil cooler from the SA. Getting lots of tips from the forum as well as “RAD Potential” on YouTube.
You don't need to cold start from either car. Just use a cap on the carb side. Mazda published a TSB instructing owners to just unplug the pump, Now, as for the Hot Start, you'll want to use the 1980. I didn't say this before, but you'll want the carb from the 1980. The tricky part is the intake manifold.
The issue is that is an open port at the bottom center of the 1980 that the 1980 manifold does not cover. The intake from the 1984 covers this port. I'd be inclined to use the 1984 manifold and the 1980 carb. In my very first RX-7 (1980). I put a 1984 engine in it. That port on the 1984 using the intake from the 1980 made so much noise (exhaust) I used JBWeld to plug it. It worked, but looking back I'm lucky none got to the rotors.
You don't need to cold start from either car. Just use a cap on the carb side. Mazda published a TSB instructing owners to just unplug the pump, Now, as for the Hot Start, you'll want to use the 1980. I didn't say this before, but you'll want the carb from the 1980. The tricky part is the intake manifold.
The issue is that is an open port at the bottom center of the 1980 that the 1980 manifold does not cover. The intake from the 1984 covers this port. I'd be inclined to use the 1984 manifold and the 1980 carb. In my very first RX-7 (1980). I put a 1984 engine in it. That port on the 1984 using the intake from the 1980 made so much noise (exhaust) I used JBWeld to plug it. It worked, but looking back I'm lucky none got to the rotors.
Ive got a Weber 48ida on my ‘84 12a.. keeping everything nice and simple
1st engines out, doing a nice deep clean before I get going on the other engine and bringing it over. Going to convert to the 84 ignition and converting the ‘84 to accept the ‘80 oil cooler. Oil cooler lines were giving me a hard time so decided to just address that when the engine is out. Also had a fun time getting at the throttle cable so I waited to get it on the engine lift and pulled away from the firewall to get more room.
