How do I know if I need spacer on Hi Torque?
 

I received my new hi Torque mini starter and it comes with a spacer. I have my old starter out and i tried to measure the difference between the two but its difficult to measure accurately and the spacer is only ~ 2 mm so its tough to eye ball.

Is there any other way to tell? I hate to chew up the ring gear with the wrong guess.

Surely this is covered in a thread but I could not see it with several searches.

Able to bench-mount and energize each, then mark reference points of the extended pinion gears?

Also confirm the teeth patterns are compatible.

Sherwood

I will try it, but again its only 2mm difference so its got to be a pretty accurate measurement and there are no really good straight edges to reference. Maybe I can measure down to a pencil mark on the bench.

Not absolutely sure, but it should be possible to bench-energize the solenoid w/o energizing the motor. If possible, the solenoid will extend the pinion gear out to its maximum extension.

Record the measurements from each starter, then compare with the distance between the starter mounting surface on the gearbox and the ring gear. The objective is to fully engage the ring gear w/o over or under-reaching it. BTW, a 2mm spacer represents pretty close fine-tuning.

Sherwood

I can energize the stock starter and the pinion come out but not the mini (it jumps out and spins), but I can pull the mini out by hand. They both appear t stick out the same amount, again difficult to measure ~2mm when there are no really good flat surfaces to gauge from.

Next I put both starters on two 2x4 scraps face down (on their mounting surfaces) and I was able to see that the Mini pinion sticks out slightly farther than the stock. So I am going with the spacer.

Excellent. Always better to confirm and not assume.

Sherwood