Qbuilt

Hello all,
I just recently swapped in a new( to me) 12a into my 83gs. However i believe the engine is a 82 or older due to the lack of eyebrows over the spark plug holes and the older flywheel being installed. I was using the clutch that came with the new engine but found it to be slipping quite badly, so i pulled the tranny and found that the pressure plate was not releasing all the way due interfering with the recess in the flywheel. Also the PP was spaced outwards with little machined 1/2 inch spacers. So I installed my old clutch (known good) and have had no slipping issues since, probally due to different PP design not interfering with the flywheel. On my 83 the PP sits flush mounted on the raised portions of the flywheel, however the 82+older FW's do not have raised portions.
Should a proper 82+older PP sit flush on the FW???
Im asking because i have a very distinct engine vibration above 5k. Possibly due to improper flywheel throwing off the balance of the engine?
Also is it possible to swap the front counterweight and flywheel from my vibration free 83 engine( blown up) to this older engine and not have a problem. Or will the rotors different weight mess this up???

Any input is greatly appreciated, as I have approx 2 weeks before i have to take this thing on a 1000km round trip, and I would like to not tow it back home.
Thank you all.
Brendan

Rx-7Doctor

iTrader: (13)

The spacers you are refeering to are used on a lightened steel flywheel with the larger 225mm clutch. The stock flywheels do not use anything on them and the pressure plates sit flat.
Was the clutch out of the donor car the same size as your 83?
Engines are balanced according to the years and usage of the correct flywheel weights. Most of the time there is never any vibration felt even with the incorrect flywheels.
I would check the condition of the trans mount. Most of the time the rubber portion seperates from the metal.

Qbuilt

Yes, the two clutches are the same size. Im a little confused about this as I thought the pre-83 clutches were 215mm and the 83 and up were 225mm. Im assuming I have two different aftermarket clutches and both were designed quite differently.
I know i currently have a pre-83 flywheel installed, and I know that I am using the clutch on this flywheel that came directly off my 83 flywheel( different design). The clutch sat flush on the raised portions of the 83 flywheel, but since there are not any raised portions on the older flywheel, spacers have to be used to use this clutch. But i was under the impresssion that the wear surface on the pre-83 flywheel would not accept the larger 225mm clutch disc.
So right now I have clutch assembly made for an 83 bolted up to an 82 flywheel. It works well and it feels exactly as it did when installed on the proper flywheel.

Thanks Rx7doctor, ill check my engine mounts tommorrow, i know the trans mounts are O.k. as i just inspected it before install.
The vibration is weird, it cant really be felt at lower rpm but when i accelerate hard when i hit about 5k i get a weird buzz/humm sound and it sounds and feels like its coming directly from the engine.????????

Kory_yahi

I had a vibration on my 2nd gen right after I swapped it to a LS flywheel with an aftermarket clutch. When I swapped it back the vibration was gone. Never exactly knew what the problem was....