I have a 1980 RX7 holding a 12a. the 12a is carb. I have a 1987 RX7 NA running a 13b. the 13b blew and i want to put the 12a into the 87 NA. Just a few questions.



a) I have heard the motor mounts are in different locations? Can you explain this to me? Where are the 12's? 13's? Does the 12a contain the location on the block to use 13b style mounts? Does anyone have online comparison of the two engines?



b) I also heard i will have to shave the block/manifolds for the 13b's exhaust? Truth?



c) Will the 12a bolt to my NA's tranny?



d) How was the 13b (internally) differ from the 12a?



e) Are the bolt patterns for the rims the same : )



Thnx for your time i rlly appreciate it.

 

Well, first a remark about your last post in the other area. If the dude could drive it around at 2,000 rpms then it could not have been totally blown. You very well may have a fine front rotor. Just my 2 cents.



Now, about those questions. I will try to answer some of them



A. Yes, they are different. 1st gen = front plate mount. 2nd gen = center plate mount. 3rd gen = rear plate mount. Don't ask why because I have NO idea No, the 12A does not have mounts to slap it in the 2nd gen. The 2nd gen 13B had the pass mount go into the oil pan like this: http://www.rx7turbo.com/mycar/small%20new%...rmotormount.jpg



B. Dunno.



C. Yes. one or two may be in the wrong location but it should mate up.



D. Bigger There is a bunch of different stuff since it was a pretty major redesign.



E. Dunno. You like the older wheels???

 

thnx for the info, maybe i can fabricate the mounts? Yea i like the rims on it more than the phone-dial style im sporting now lol.

 

Yah, you could make them but I am sure someone sells them.

 

b) they changed the bolt pattern too, so you would need to make some sort of adaptor, and even then the 12a doesnt have injector holes in the block



c) yep



d) the 13b has wider (by 10mm) rotors, and the 86+ 13b's have 2mm apex seals, and the water seals are in a different spot



e) nope



mike

 

AS for E:You can use 4 lug FC rims if you swap on a set of GSL-SE brakes.



You should use the front cover,oil pan and dipstick off the 12a to make the 13b drop in.Or else you'll have to fab custom mounts for it.

 

um, he's going the other way



J