ring gear for Fidanza flywheel

G

Greg Nagy

Well-known member
Does anyone know if the stock ring gear for the 1275 sprite/midget is the same as the one used on the Fidanza Al flywheel. If not, what is the ring gear from?
 
I emailed them, with no response.
I know calling would be better, but I have been unable to make calls during the daytime hours this week.
 
It's been years since I dealt with them, but I do remember doing it over the phone. I just needed a new friction insert for a flywheel, but it wasn't a problem to get a new one ordered and shipped.
 
As far as I can tell they use a normal stock type ring gear with one exception, they drill and tap halfway thru the ring gear and aluminum flywheel to pin the flywheel,and ring gear. I think if I had to do this job, I would get a new stock ring gear, remove the old one, put the flywheel with installed new ring gear on the milling machine use the appropriate end mill to put back the hole half way in the ring gear and flywheel, then use a helicoil there instead, or maybe even use a counter sink allen head bolt with a jam nylock on the other side, that would be a easier way to duplicate it in the future, if I had to replace the ring gear again.
 
Most engines come to a stop in the same position within a few degrees. (I don't know why!) This exposes just a few ring gear teeth to initial starter engagement, leading to excessive wear of just a few teeth.

Are all of your ring gear teeth worn, or just a few in a limited area?

If the latter, try repositioning the flywheel 90 or 180 degrees (balance permitting), or if the flywheel is doweled, reposition the ring gear on the flywheel to expose different teeth to initial starter engagement. Either way, re-balancing is recommended.

RJS
 
No, it is not in just one place. I am not sure WHAT happened, but all the teeth seem to be rounded down, and I also have a brand new starter with a destroyed gear as well.
 
Mounts solid? everything lined up properly? Bendix in good shape? sounds like something isn't lined up right...
 
Greg -- Check to be sure the starter pinion is fully disengaged from the ring gear when retracted. I've seen gear reduction rebuilts that did not fully disengage (or did not fully engage). On one I had to grind about 5/16 from the leading edge of the gear teeth to get decent clearance when disengaged. It's best to check all this on the bench so you can really see what's going on.
 
Also............. if the Bendix drive return spring is weak and/or the clearance is low per Randy, the stationary starter drive gear will move forward enough under hard braking and hit the rapidly spinning flywheel ring gear teeth. You'll know it though as it makes a terrrible clatter.
 
The word from Fidanza is that it is a stock ring gear.
They say to mount the new gear and then mill the openings for the positive fasteners.

The starter I had on the car for the last race was a new one, and not checked on the bench. The next one going in will be.

Thanks everyone.
 
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