So im swapping engines out right now and pulled my 12a engine yesturday. The engine im putting in is a 1980 12a...

I was trying to figure out what clutch setup to order because the 1980 should have a 215mm clutch disc but the one it has is a 225mm which is what matches my 1985..

But the pressure plate that was being used on this 1980 12a was a 215mm......???? Is there a reason a 225mm disc was being used with a 215mm PP?????

My 225mm disc off of my 1985 engine fits on the 1980 engine but my PP doesnt work......?

Has anyone else had this problem and what should i do about it..........

 

In a old thread i had there was alot of mixed views on swapping my 85' 12a flywheel onto this 1980 engine because it was screw the balance up and cause my engine to only last a few thousand miles.....so i dont know if i would want that....... but seeing as my flywheel now is a 225mm flywheel i still dont know??

 

Best bet is go with the 215mm, if it came from the factory that way, oods are you should keep it that way. why take the risk?

 

I ran into a silimar problem. I have a 1985 GSL (225 mm flywheel). I purchased a really nice zero mile Atkins Rotary rebuild but is has a 81-82 215mm flywheel. I don't want to risk anything so I'm sticking the the clutch correct 215mm.

Something to think about. If sticking with the 215mm flywheel, do we also need to change the starter?

 

but the flywheel on the engine now is a 225mm even though it should be a 215mm....

Should i just go and try to send my clutch kit i ordered back and get one for a 1980...215 clutch disc and 215 PP.????? even though the flywheel on the engine now can handle the 225 and had a 225??

 

I didn't read your first post very well. Now I understand. If you havn't already identified the flywheel, look at the web site.

http://www.mazdatrix.com/faq/flywheel.htm

So you have a 225mm clutch on a 1980 motor that needs to go into a 1985 RX-7. I would first make sure what year the flywheel on the 1980 motor is. Whatever that flywheel is, I would stick with the same year clutch and PP. Who knows that internals are in the 1980 motor. That is what really determines what flywheel to use.

 

It looks like the 79-80' flywheel but shouldnt that mean it is a 215mm flywheel and not 225mm or are they all 225 but use a 215 clutch??

 

It is the 215mm flywheel then. I would use a 215 clutch and pp.

 

but the clutch disc that was used on this 215mm flywheel was a 225 clutch disc so how was that possible

 

The larger disc can be fitted between the 215mm flywheel and PP, although it may not fit correctly. The PP's have a different bolt pattern, so you will have to use the 215mm PP.
Best bet, would be to trade your new 225mm set for a 215mm. You're not loosing that much clutch surface, and will likely never see any difference in clutch holding power, unless you have a very modded engine.

 

I think so, here's why.
I recently swapped an engine in a 79, went back with an 85 out of an auto. Put the proper 85 flywheel on, which just happened to need a new ring gear. Before I installed the ring gear, I compared it to the 79 flywheel ring gear, and it looked to be identical. Yet, when I put the 79 starter back on, it didn't contact the flywheel. I ended up using the starter I had just gotten rebuilt for my 86. The 79 starter and 86 starter looked almost identical, other than the diameter of the drive gear. Even the depth of engagement (distance the drive gear moved) appeared to be the same.

 

I may be wrong on this one, but I was thinking all the manual NA flywheels are same diameter and the autos are different. I do know that the TII and FC auto starters and ring gear diameters are the same and the 83 on NAs are the same. Just not sure about the early 215 mm NA ones though.

 

Trochoid, I was hoping that either you, doc, or wackyracer could give a more deffinate answer.....
I based mine strictly on my experience. Note, all measurements I done, were with the naked eye. While they aren't micrometer acurrate, I not blind, yet......