The early seals can be reused for years. In the olden days we milled the fat seals down to fit the later

3MM rotors. Works fine. The thin bolts are fine. You can run a later rear iron, but check to see if you will need to plug a bolt hole in the rear rotor housing to keep coolant out of the sump. Go easy on torque on that plug as you will distort the housing.



The Mazda trans uses the bell housing center as the front of the trans. That adds to the work.



You can adapt the early bell housing to any flat faced trans with a flat plate adaptor. Practacly any flat front Mazda trans can be fitted to the early bell housing. You have to cut out the center of the bell housing and use the bearing retainer from you new trans.



Or, you could put the old front cover on a later engine and it would look authentic to the unwashed, with nearly no trouble at all.



I used to make up button flywheels and spacers so I could use Porsche Super 90 clutch covers. I welded the Porsche disc to a Mazda center (Ithink a Volvo disc is the same as well)You just bolt that flywheel on over a stock early flex plate. I used the smaller top mounted starter by slotting the mounting holes in the mouning flange on the starter. I just used the two studs close to the parting line rather than all 4. Now you have a fast reving engine with clutch pack, disc, and flywheel at about 7 pounds. Plus the parts were cheap. Take the lining off of the disc and epoxy it back on. Use the clutch cover as a clamp. Cover the cover pressure plate and flywheel with Saran wrap or baby powder to prevent excess epoxy from sticking to the pieces. Mazda's have no torque down low so for NA engines do not need monster clutch pressures and big covers. Racers use the smallest diameter covers made. I used 5 1/4" but now they have 4 1/2" covers. The Super 90 is about the standard 7 1/4".



We also cut the centers out of VW flywheels, if you can stand a bit more weight. Also bolted on over the stock flex plate. If you will do big revs, TIG the ring gear on both sides all the way around, as they tend to break into segments and machine the bell housing into two pieces.



Lynn E. Hanover

 

The dual side seals would be more reliable for compression but would eat up the irons faster wouldn't they? And holy massive apex seals! If the carbon ones are more reliable, why doesn't anyone supply them anymore?

 

mazda sells carbon seals still, just not the 5mm ones, they sell 3mm 12A and 13B, and 2mm 13B.



and more reliable in this case means that they are easy on the housings, and seal well @high rpm, because they are really light, but they will wear more quickly.



the weight difference between a 3mm 13B seal and a 5mm 12A seal is really dramatic actually