gbgastowers

I have an 82 Euro S 5spd that hasn't run in a while and the po recently put a new starter on it and tried to get it started. It finally did start for him but had oil blow by through the exhaust. He shut it down after about 30 seconds and sold it to me. Anyway-here is what the ring gear looks like. What causes this? I was thinking I would put it back in till I get the car running smoothly then replace the clutch pack later when it's more worn out.

Imo000

starting the engine while running can do this and so would a missaligned or wrong starter too.

Randy V

Yep, those are pretty much the main reasons for your problem.

SteveG

Or, weak bendix (weak spring that causes the starter to engage w/ring gear). Assuming it is the correct starter, working properly (it needs to reach a certain rpm in the correct time to overcome the spring and engage) it can be re-built.

Mrmerlin

since only a few teeth are damaged i would think that the engine was seized or otherwise wouldnt turn.
if the starter was engaged while it was running then all of the teeth would have damage.
Its also a possibility that the wrong starter is installed.
NOTE, the way you have starter in your picture is 180 degrees from the correct position , the solenoid is mounted so that its under the oil pan

gbgastowers

That's how the starter was mounted when I got the car. So your saying I need to rotate it for the correct position? That explains the damage to the ring gear.

Mrmerlin

turning the starter 180 degrees will position it correctly in the housing but it wont change the depth of the starter to its mount

Roy928tt

I've answered this question over on Pelican as well but here goes again.

Engines generally stop in the same position every time, sometimes more than 1 position but always in distinct positions. Thus when you start the engine the starter engages the same teeth on the flywheel every time, after 30 years your flywheel looks like the one in the photo, which by the way has an awfull lot of life left in it.

As can also be seen from the photo, Porsche didn't bother to cut a lead in on the teeth on the flywheel, so the starter bendix simply gets thrown out, crashes into the teeth of the flywheel and then starts to spin resulting in damage and wear on the flywheel teeth.

I'm suprised at some of the nonsense thrown up, by people I was begining to believe knew better.

This is totally normal wear found on every flywheel.

Cheers Roy

Imo000

You have a valid point BUT why the hell is the starter brand new in the picture. My logic is that there was something wrong (besides normal wear and tear) with the previous one and that's what cause the extensive damage. This is not normal wear, even if the flywheel is 30 years old.

Tails

Dress up the teeth or the ring gerar where worn with a slight chamfer on the leading edge profile by file to get good engagement.

Chech the thrown "in" distance of the starter's spur gear to check if you have full mesh of the spur gears.

Change location of starter motor by 189 degrees as Stan suggests.

I have seen worse worn ring gears.

Check the system in operating condition to verify engagement. if no non engagement then all is satisfactory for use.

It is your call.

Tails 1990 928S4 Auto

gbgastowers

Merlin- look how Sharkskin has his starter installed. I'm going to flip it but this confuses me. http://members.rennlist.com/sharkski...tesTorqued.jpg AND http://members.rennlist.com/sharkski...ine_Mounts.htm

Dave928S

Here is a photo from the Blue 82 (James Morrisons now), when it was for sale, that shows the factory orientation. I keep all the photos of that car in a folder as a handy reference for the way things are supposed to be. It wouldn't practically make any difference which way you have it, other than where the solenoid and cables are oriented. You could I suppose mount an argument for each orientation based upon susceptibility of the solenoid and cables to heat, oil leaks and impact .... but if it was me I'd go factory and get a better fit and location of cables.

Ring gear wear ... Roy is right in saying that when the starter engages that it crashes into the teeth and causes some wear ... but my ring gear hasn't got that degree of wear, and to me it looks excessive. It looks like there may have been a problem in the past with a dicky solenoid maybe, which caused slow meshing and accelerated gear wear, and the new starter does suggest a past issue. He is also right in saying that the ring gear settles in only a few locations and that's where you get all the wear. An old remedy is to rotate the ring gear to a new orientation so that fresh undamaged teeth are exposed to the starter gear. As you've lost some metal from teeth anyway, I don't think doing that is likely to have any balance implications.

Clutch .... clean up your flywheel face, pressure plate face, and intermediate plate faces, and check ball cup wear, input shaft, and pilot and throwout bearings as a minimum before putting it back together. WSM has checking procedures and measurements. No point not attending to a clutch issue while you have it out ... because believe me they're a bitch to drive with a dodgy clutch. Adjustment on twin plate clutches is critical to correct operation too. Search and you'll find a few threads on twin plate adjustment.

Roy928tt

I visited my 928 today, started it about 30 times and turned it off, I noted where the engine stopped, it stopped in 4 distinct areas. Interestingly about 80 percent of the time it stops in one of two areas and the other two areas account for the remaining 20 percent of the times, so from this I would expect to find 2 areas of wear on the ring gear.

Cheers Roy