Heavymetal, no disrespect, but you also haven’t told us whether you still have the original starter. If you do, it’ll give you some valuable dimensions to compare the replacement part with.
You could even measure the extension of the starter motor gears when the solenoid is energized by just applying 12VDC. I’ve never tried it, but if you’re uncomfortable using the car’s battery and don’t have a separate source (like a power pack), two 6VDC lantern batteries connected in series might be just enough to operate the solenoid long enough to take a measurement.
Or, since the original was still working properly, perhaps you could just install the original back in and return the new one for a refund.
I cannot envision any way the motor could spin unless the bendix assy was activated and the contacts engaged, so it almost has to be either
- insufficient gear extension,
- improper shimming,
- missing ring gear teeth, or
- a center-to-center dimensional problem between the starter housing mounting holes and the starter motor shaft such that when the motor is mounted the starter shaft is too far removed from the flywheel centerline to allow engagement. You’ll need to check some measurements before returning the assembly.
If you’re not sure how to measure the dimensions from the bolt holes to the starter motor centerline, just clamp a piece of scrapwood to the benchtop, drill a hole the same size as the starter shaft (or gear O.D.), stick the starter in it, mark the mounting hole locations, drill them out on the wood, set the starter assembly aside, and measure the center-to-center of the holes on the bench.
You can get a pretty accurate measurement by sticking drill bits into the holes, measuring the outside-to-outside dimension (tangents), and subtracting the total of half of the radii of the drill bit at each end of the measurement. That’ll get you well within the tolerance necessary to tell if the bolthole-to-motorshaft centerline dimension is consistent with the original assembly.
The key to doing this is having the original assembly. Once again, do you still have it?
Post back. We do care.