flywheel ring gear

[ROWDYRENAULT]

It seems that I have knocked a tooth out of the ring gear on my flywheel. This seems to be an odd thing to happen its all factory parts and the factory has already told me the ring gear to replace it with. My question is has anyone seen this problem before and am I missing anything besides just replacing the ring gear and a visual inspection of the starter? Lee

[Storer]

Hi Lee

Had a similar issue but my starter was the wrong one (not supplied by the factory).
The teeth were not fully engaging all the way onto the ring gear.

We are asking quite a bit of these components with 33% more cylinders per rotation and a greater rotational mass, so it is a wonder we don't have more issues.

The ring is easy to change, its just the time it takes to get the box out that sucks.


Paul

[ROWDYRENAULT]

Thanks Paul: My setup is all factory so I think the starter is good as is we will see when I get it out. Lee

[Swiss_Toni]

Hi Lee

My set is very bespoke (rear mount starter with a shat), though I have found alignment is critical and also clearances for both for the distance of starter gear front face to aft face of the ring gear (side closest to starter) and radial distance (tooth engagement).

I don't know if your setup has shims to adjust either.

[Nabbott]

Lee, I had just this issue - pretty easy to fix, if a bit of a ball ache. When I spoke with the factory they highlighted the stress that all the starter components are under. If your engine has ever spent anytime running poorly a backfire upon startup would be enough to shag a tooth.

[ROWDYRENAULT]

I think Nigel may have hit on the truth. I had taken the Kinsler off for service work and when I went to restart it did pop a couple of times before all was well in start up land. Right after that is when I started having troubles with a blank spot on the starter, Of course when I rolled the car forward a few feet while in gear then the car would start as normal. Lee

[JoulesCanAm]

Lee,

I had a similar issue with starter engagement not quite aligned and wearing outer teeth on the flywheel in one spot. I hadn't considered the backfire scenario, but my car does cough and sneeze when cold, so a plausible hypothesis.

Julian

[2001ultima]

Yes, I have heard that backfiring can cause the problem.

The following information and link below provide some good information. I'm reading about 9 and 10 tooth starter pinions, 9 being Porsche OEM and 10 being a possible solution. But with the 10 tooth if you buy one you need to make sure that the teeth have a chamfer on both sides. If not, that could also be why the starter pinion teeth and ring gear can get chomped up a bit.

See link below. This person installed a 10 tooth starter pinion which was longer in length as well BUT machined the opposite side of the pinion teeth to create a chamfer on the opposite side and this solved the problem. Note the OEM pinion has a chamfer on each side.

http://forums.pelicanparts.com/porsche-911-technic...

"The special 10 tooth pinion that IMI supplied, has the chamfer on the wrong side of the leading edge of the teeth - hence the issues with the occasional grinding on start-up." "Therefore I machined a chamfer on the opposite side of teeth and it is now working properly."

IMI Performance = http://www.hitorque.com/default.asp

Another link but not much help:

http://forums.pelicanparts.com/porsche-911-technic...

[Nabbott]

Lee, I had just this issue - pretty easy to fix, if a bit of a ball ache. When I spoke with the factory they highlighted the stress that all the starter components are under. If your engine has ever spent anytime running poorly a backfire upon startup would be enough to shag a tooth.