Starter Pinion to Ring Gear mesh - SOLVED
 

I'm hoping someone has info on the correct spacing of the starter pinion gear to the ring gear. This, and/or specs on the pinion gear itself. Something is terribly wrong with mine...

The 928 in question is an 85 5 speed. To my knowledge, the starter mounting is fixed, hence no adjustment possible at the time of installation... Just replaced intermediate plate with a virtually new one and after about 50 or so starts am getting grinding sometimes on hitting the key.

When installing the intermediate plate, I also replaced pilot bearing, TOB and clutch fork pivot bushing. Starter was also replaced with a second hand unit. Pinion on the starter "appeared" to be good - little to no wear. Worked great for the first day or two, but I did notice an occasional "thunk" or "click" when the engine fired. Later that noise became a "scrape" noise. Now I'm back to tooth-gnash on hitting the key.

I believe the starter I installed may not have been retracting properly. I've since disassembled, cleaned, lightly lubed (with bearing grease), reassembled and tested out of the car. However, looking at the tooth spacing it looks far too open to work properly... (see attached)

I wanted to get any info possible before I try running the car again. I've already marred my once pristine intermediate plate and don't want to destroy it... ($450 or more to replace it again)

First pic is of pinion-ring gear tooth mesh. Last two pics are of pinion gears on the two starters I have. Both starters test properly (strong solenoids, good return on drive, strong motors).

If it's a reman' starter, it's possible to have the wrong pinion gear. I've seen it.
I don't think that's your problem though. You probably just need a new starter with new mechanism. I'd call 928 Intl for a nice used one before risking a local reman but that's just me.

With the starter installed for Pic #1 (solenoid off, manually extended) I noticed a fair bit of radial play on the starter axis at the pinion end - I could move the pinion back and forth a bit by hand. Seems to be this way on both starters I have.

Does anyone know if THIS is typical as well? It's seeming like these are both scrap, but perhaps not...

I doubt it should move much. My guess is the nose of your starter is shot.

Time doesn't afford me the opportunity to ship from Calif, so a reman is on order. I'll see what it looks like when it arrives. Here's hoping...

New (rebuilt) starter received. Play on the pinion gear IS less than on my other starters. Gear mesh to ring gear is the same. After installation obtaining the same results.

Tomorrow I'll begin disassembly - through removal of the flywheel to ensure the starter bracket is properly secured to the rear face of the block. Not that I'm crazy about taking this on, but this appears to be the only remaining item to verify. I don't see any possibilities for shimming, options for tweaking the gear mesh or other means of improving the situation.

That being said, any other experience with this type of issue is still appreciated :)

Flywheel out. Starter bracket was secured only by the two allen bolts, parts diagram I have from Pelican shows four bolts total. (2x M8x48 Hexagon Head bolts missing completely?). The existing lower bolt was not fully tightened. With the locating sleeves between the bracket and the block there still was not a lot of play in the bracket. However, during use the movement could be more than I'm able to manually affect on the bracket.

The plan is to get the additional bolts and check mesh with just the flywheel, starter and intermediate plate/ring gear installed.

Your comments and insights from your experiences are still welcome and greatly appreciated...!

Starter Pinion to Ring Gear mesh - SOLVED
 

Securing the starter bracket with the requisite number of bolts has a marked affect on starter operation... On first test of correctly installed unit, I initially thought the starter was bound and not cranking - it was running THAT quietly. It IS a beautiful thing.

How or why it was installed without the two M8x48 bolts is a mystery. I've had the car for three years - based on the dirt/oil build-up in the lower of the two vacant holes, it has been that way for quite some time. Oh, well - fixed now, and fixed properly :D

As an aside: I am such an enthusiast of this vehicle - as a driver AND as a mechanic. The engineering Porsche invested in this vehicle is simply remarkable and is evident throughout. With this job, for example, once my new rear crank seal was in hand (a necessary mission creep add-on) reassembly took only 3.5 hours, including removal of the old seal and a couple of rest breaks. This also included refitting exhaust and shields, starter fitment, refitting stabilizer bar center bushings, refitting front wheels and bringing the car down from jackstands. I performed the work alone and it was all straight-forward - no fiddly, impossible to reach items - no complex, curse-inducing painful steps. A remarkably engineered vehicle and I'm ever grateful to have one!

Great to hear that you got it all worked out. Sometimes you just have to 'shake your head' at the PO's work. It would have taken less than a couple of minutes to put those two bolts on and not have any parts left over..