compatibility question
10-26-20, 09:47 PM
#1
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Thread Starter
compatibility question
I have a 79 sa w 12a and 4 speed. in the event I need a motor, what other year rotarys/trans are compatible with my car? I located a few possible motors/transmissions, but not sure about compatibility between different generations, 12a vs. 13b etc. i've seen a few things about that, but not sure where to look here for that info.
10-27-20, 12:11 AM
#2
poke around the Gen 1 section and you can soak all the fine details of many combinations. most things are swappable between the SAs and FBs.
suffice it to say, you can use any 12A in your car, generally speaking. there are some external differences here and there (e.g. EGR passages, flywheels), but nothing insurmountable. they bolt in - no drama.
as for transmissions, it's pretty much the same deal there - SA and FB. i'm not 100% sure on shifter locations between the two, but i have a vague memory of putting an FB tranny in a friend's SA, and i don't remember doing anything but bolting it in.
13Bs are a little more complex because now you'd start having to buy parts (and the parts are not necessarily cheap) and/or do real work to convert things. getting the engine in the car is actually fairly simple - 13Bs are a little longer, so you'll need a new or modified mounting bracket. aside from that, finding an oil pan (GSL-SE is probably the best option) is the only other physical hurdle for getting it in the car. Gen 2 engines are easier than Gen 3 engines because of the oil pan and front cover bolt patterns, but even the REWs are not too bad. getting it to run will vary from relatively easy (carburetor) to somewhat complex (EFI). just note that i did not include the 13B from the Rx-8 in that though. it's a somewhat different animal and deserves it's own conversation. also, i'm not considering keeping OEM turbocharged engines turbocharged in what i said either. that is probably best explored in a separate conversation as well.
for 1986+ trannies, any of them will bolt to the engine with the right flywheel setup, but putting it in your car will be more difficult. the Gen 2 trannies are probably the easiest, because all you'd need to do is swap tail housings and mounting brackets. the Gen 3 and Rx-8 are doable, but again, a different story.
suffice it to say, you can use any 12A in your car, generally speaking. there are some external differences here and there (e.g. EGR passages, flywheels), but nothing insurmountable. they bolt in - no drama.
as for transmissions, it's pretty much the same deal there - SA and FB. i'm not 100% sure on shifter locations between the two, but i have a vague memory of putting an FB tranny in a friend's SA, and i don't remember doing anything but bolting it in.
13Bs are a little more complex because now you'd start having to buy parts (and the parts are not necessarily cheap) and/or do real work to convert things. getting the engine in the car is actually fairly simple - 13Bs are a little longer, so you'll need a new or modified mounting bracket. aside from that, finding an oil pan (GSL-SE is probably the best option) is the only other physical hurdle for getting it in the car. Gen 2 engines are easier than Gen 3 engines because of the oil pan and front cover bolt patterns, but even the REWs are not too bad. getting it to run will vary from relatively easy (carburetor) to somewhat complex (EFI). just note that i did not include the 13B from the Rx-8 in that though. it's a somewhat different animal and deserves it's own conversation. also, i'm not considering keeping OEM turbocharged engines turbocharged in what i said either. that is probably best explored in a separate conversation as well.
for 1986+ trannies, any of them will bolt to the engine with the right flywheel setup, but putting it in your car will be more difficult. the Gen 2 trannies are probably the easiest, because all you'd need to do is swap tail housings and mounting brackets. the Gen 3 and Rx-8 are doable, but again, a different story.
10-27-20, 09:35 AM
#4
the rotor and rotor housings on the 13b are thicker, making the entire assembly longer. will require fab work to the front mount. any 12a will bolt in although emissions did differ. any trans from 81 on will need fab work for it's mounting and shifter position.
11-07-20, 10:03 AM
#5
Engine, Not Motor
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An '88 (S4) engine is completely different in every way than your 12A. 
It is an EFI controlled engine, thicker, mounts at the center iron not the front cover, the transmission is longer with different mounts, etc. etc.
You could make it fit with some work such as swapping 12A front cover, make transmissions mounts, shorten shift housing, 13B carb manifold, etc.
It is an EFI controlled engine, thicker, mounts at the center iron not the front cover, the transmission is longer with different mounts, etc. etc.You could make it fit with some work such as swapping 12A front cover, make transmissions mounts, shorten shift housing, 13B carb manifold, etc.
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