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Discussion Starter · #1 ·
It's been awhile but I'm back for more help. If you're not familiar with my conversion, I'm using a 1986 Mazda RX7, an ADC FB1-4001 motor (I think that's the right model's been awhile) and Electro Auto's transmission adapter kit. I'm FINALLY getting to put the motor in, after an exhausting battle to get clutch parts that fit. Now I'm having trouble when mating to the trans mission. Here's what's going on:

-The motor and parts all seem to mate easily. It only takes a short time to lower the motor into position, line it up, and bolt the adapter plate to the transmission. The slave cylinder and throwout bearing appear to function correctly from the outside, moving appropriately when the clutch pedal is depressed and released.

-Prior to mating, the motor spins fine when connected to a battery. Also, when in gear, the spline shaft of the transmission turns the correct way when pushed. In other words, as best as I can tell, both components of the issue seem to work separately.

-After mating, the car can be pushed forward or backward when in neutral. I cannot be pushed (with two people) when in any gear, even when depressing the clutch. With the back wheels off the ground, the motor will not spin with power applied, whether in gear or in neutral.

It looks like the problem is with installation, which is good because these are two things I'd rather not have to replace or service. Any ideas? Thanks in advance.

Admin: 'one of many'
4,838 Posts
If you depress the clutch will the motor spin?
It could be the clutch is misaligned and also the clutch may not be releasing if the flywheel to adaptor distance (the magic number) is wrong.

Otherwise one possibility is adaptor missalignment the other is end thrust.

With the motor well supported by a crane or jacks, loosen the bell housing bolts but don't remove them, just allow the motor to be pulled back 1/4" or so and pull the motor off the trans that amount but keep it supported so it is not sitting on the shaft.
Everything should still be coupled up.

Select neutral and turn the back wheels by hand. Then select each gear in turn and turn the wheels. The motor should turn freely with the wheels, at least in 5th gear as the lower gears will be harder to turn by hand.
Slowly wind the bolts in a little at a time and keep turning the wheels and checking the motor turns freely.

Just before the bolts are all the way home the motor may start to bind.
If the motor binds suddenly when there is still a gap between the adaptor plate and the bell housing then it could be end thrust, the adaptor plate is too thin or the coupler too long.
If it binds gradually as the bolts are wound in then it is probably alignment. You may even see the adaptor plate try to wobble.
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