Is there any appreciable differences between NA engines from a 86-88 and 89-91? I am thinking about dropping a 90 NA into my 87. Are there computer differences? Would I need to change anything? Also, engine is from an automatic and going into a manual. I know I would need to change the flywheel and front counterweight and of course a pilot bearing. Anything else? Any advice would be greatly appreciated.

 

there are ALOT of little differences. you would need to screw around alot to get it to work. you are much beter off to find a 86-88 motor.

 

No, no, that is all wrong.

There are many differences. It can be made to work, but it really isnt worth the extra effort for a backyard mechanic. IT will also be very hard to pass an emissions test if you did so, as the 89+ block has no EGR.

Basically you would a) keep the front counterweight and rear flywheel from an 89-91 nonturbo on the 89-91 block; the pilot bearing for all 2gens are the same, dunno who fed you that bs. You would change from the 86-88 motor you had and put onto the new 89 motor: front cover, OMP, intake, wiring harness, injectors, fuel rails, throttle body.

Basically, your aim would be to have an 89 block and all 86-88 externals with exception of the rotating assembly, which must match the block. For instance, your 86-88 flywheel would not work on the 89-91 engine, or there would be balance/vibration/longevity issues.

 

Thanks. Quite helpful! Where's the best place to get a complete rebuild kit and gasket set for the 87 motor?

 

I get all my parts from atkinsrotary.com. Theyre very nice and helpful, and their prices are great. I do not buy a "kit", just the parts I know I need/want to replace: gasket kit with coolant seals, apex seals, oil o-rings, oil thermo pellet.

Also note that it is common for at least one rotor and rotorhousing to be damaged in a blown apex seal motor, and require replacement in order to rebuild. You can get these used for $25-100 per piece.