Here are the pics of the starter alignment and the collection of rings I`m starting to accumulate. I betcha I can R&R that engine blindfolded now!! Did I mention our driving season up here is fairly short.

http://forums.pelicanparts.com/uploa...1340073510.jpg


http://forums.pelicanparts.com/uploa...1340073546.jpg


http://forums.pelicanparts.com/uploa...1340073583.jpg

Starter must be running while the engine is running somehow. Maybe some fault in the ignition switch possibly?

Does the starter engage normally ???

Are you sure it goes back after starting ???

The starter sounded perfect when it was working. It definitely disengaged properly when I let go of the key. I found this link last night which looks exactly like mine.
http://forums.pelicanparts.com/porsche-911-technical-forum/558692-3-6-conversion-starter-problem.html

Where are these rings being manufactured?

It looks like the starter teeth are hitting the bolts that hold the ring gear (based on condition of the bolt) Is that possible?

The starter teeth are fine. The bolts are chewed up from the chunks of teeth that flew off the starter ring. There were pieces of teeth everywhere. One piece even left a huge groove in the bell housing of the transmission! Before the teeth broke there was no unusual noise at all.

That may be a clue. The velocity that is required to wreak havoc like that could only be with the engine running, wouldn't it? The starter doesn't spin the engine over that quick. Maybe as suggested your ignition switch isn't telling the stater to come back (some of the time) and you just can't hear it.

Long shot but. Are locating dowels still in place between the engine and trans? I can,t recall what should be there originally but without them could the bell housing be slightly offset from the block?

Wouldn't that ruin the starter as well?

In both cases, the teeth are chewed away at the exact same place, where the engine stops and the starter initially engages.

Dowels are definitely in place. Flywheel is even all the way around.

Wow, that is pretty amazing! If you think it might be a bad batch of ring gears, post a wtb a ring gear and get one that is used and test it.
If the starter was running/engaged on the RG, you would hear it, ask me how I know because it sounds like your engine is about to let loose? I have posted this a few times and it worked for me when it was hung up, shim it.

I think you should call Jim Patrick He's done an awful lot of these
Patrick Motorsports - Custom Porsche racing parts and services.

He must be hearing something when those teeth shear off.

I definitely heard it. It almost sounded like a backfire quickly followed by grinding and then free spinning of the starter. The sound/spin was almost instantaneous.

Is this happening right when you start it, and then the noise goes away (minus any teeth rattling around), if so then the starter is not hanging up as that sound is continuous?

That's a classic timing problem, to much advance on either the cams or the distributor will destroy starters and rings as the engine backfires during cranking. The starter is spinning one way, and the engine another.

The engine has never been touched. It only had 26K miles on it in 1999 when the car was smashed. The engine runs really well, I also had it on the track the week before the second ring gear went and everything was perfect. Startup was almost instant with no hesitation and never any pinging. I will double check the alignment of the two distributors after work just in case. Also, with the first ring I used the starter quite a bit before the DME was hooked up to get some new oil through the engine and make sure the lifters pumped up. I had a tapping noise develop which I thought was the lifters but now believe I had chipped a tooth off during that sequence. As you can see I'm back and forth with my thoughts. The timing issue seems to be the only other potential cause so far. I'll definitely have it checked out once it's running again. My dilemma now is what other options of ring gears are there. I'm a little hesitant to go the same route again. I do like the used ring suggestion. Too bad I got rid of my original one.

With the amount of time and money you're putting in, I would run this engine on a stand so I could see what was happening real time with the ring gear.

with the way the teeth are broken, mostly on an angle toward the starter, maybe the hi-torque starter is the culprit. if the starter teeth engage the ring gear teeth too far out toward the tips of the teeth, they would have a lot more leverage to break them off. same if the two gears were not fully engaged across the full width of the teeth. are there any witness marks on the other teeth that may support that idea? i think i would go back to a stock starter. they work just fine.