The difference is 15mm of diameter, which may not sound like much...but it is. It's a heavier duty clutch, that they put on the 280 2+2's and turbos. I upgraded mine, with the Fidanza flywheel (which is drilled for both size clutches) which is cool. The 240mm clutch also uses a shorter throwout bearing collar to match the "taller" thicker plate. I highly recommend this if you plan on gagging it.

 

Assuming I still wanted to use the 4 speed, could I put a 280ZX friction disc on the output shaft of the 4 speed? Of course, I would be using the 280ZX flywheel, clutch cover, and pressure plate, since they just bolt on to the motor (and have matching diameters). I would probably also want to use the 240Z throwout bearing because I know it will fit on the 4 speed output shaft.

Since the 280ZX flywheel has a diameter of 15 mm greater than the 240Z, will there be an issue of clearance in the 4 speed bell housing?

You confused me a bit on the whole throwout bearing collar thing (terminology). Is that a piece between the pressure plate springs and throwout bearing or between the clutch release fork and throwout bearing? Or is it part of the throwout bearing itself? Will I have any problems with these throwout bearing modifications fitting on the 4 speed output shaft?

Or if I wanted, would it be possible to put a 240Z flywheel on a L28ET and use all the 240Z/4 speed clutch hardware? (Even if they aren't as strong, would it physically fit on there? I would most likely choose the more durable clutch equipment though.)

 

its all the same for the clutch and flywheel for the 225 mm clutch. when you go to the 240 mm clutch which is out of the 2+2 and the turbo the flywheel is no bigger, just the surface area where the clutch disc touches is wider on the 2+2 flywheel. alos the bolt pattern for the 2+2 is bigger so you can not interchange the two clutches. make usre you get the flywheel bolts that go to the back of crank from the 2+2 or turbo car, because the bolt head is shorter. i found this out this morning when we tried to put the clutch cover and disc in the car and 225 mm bolts on the crank where touching the disc springs. we ground them down about 1/8 of an inch and it worked. i will be fireing it up later today with my rebuilt trany. i cant wait!! its been a month without driving my car.

i want to thank TONYD for your help on the flywheel and HAN for the great deal on the clutch and disc and MICHEL"S tranmission shop for the great deal on the rebuild.
good luck
leo v 80zx

 

Okay, almost have the full solution...

So basically, a 240Z flywheel won't bolt onto an L28 crankshaft; and the contact areas of the flywheel, friction disc, and pressure plate are different between the 240Z and 280ZX. So I have to use all 280ZX clutch hardware because I can't use a mix of 240Z/280ZX flywheel, friction disc, pressure plate (different surface areas) and I cant use the 240Z clutch hardware because the flywheel won't bolt on. Now the only issue is whether or not the 280ZX friction disc will fit onto the input shaft of the 4 speed trannie. So are they compatible? Also, will a 280ZX throwout bearing fit with the 4 speed input shaft and clutch release fork?

 

Okay, almost have the full solution...

So basically, a 240Z flywheel won't bolt onto an L28 crankshaft; and the contact areas of the flywheel, friction disc, and pressure plate are different between the 240Z and 280ZX. So I have to use all 280ZX clutch hardware because I can't use a mix of 240Z/280ZX flywheel, friction disc, pressure plate (different surface areas) and I cant use the 240Z clutch hardware because the flywheel won't bolt on. Now the only issue is whether or not the 280ZX friction disc will fit onto the input shaft of the 4 speed trannie. So are they compatible? Also, will a 280ZX throwout bearing fit with the 4 speed input shaft and clutch release fork?

 

Oops, Double Post...%*#$ Computer!!!

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