3 starters , 2 ring gears

[nospiners]

87 G50 with a newly rebuilt motor , i have gone through 3 different starters , and 2 ring gears , still the same crunching noise every time. Clutch and flywheel set up , all OEM , very smooth , very engaging.. Checked the flywheel # , per Porsche dealer is correct


First starter OEM , had it rebuilt
Second , new Bosch s68x Part #
Third , High Torque from our host , also the new second ring gear
I do not want to just keep throwing money at the problem , i can get new clutch kit ,
I,m not sure it will fix the problem.
Any help would be appreciated , i,m at a loss for answers here..

[PeteKz]

Ugly. It looks to me like the starter gear is not fully engaging the ring gear. Does the starter fit all the way into the hole in the housing, and not cocked sideways?

[gecc]

There is a tech bulletin regarding starter seating depth for the 1987 Carrera . Only a small number of cars were affected. I would check this before replacing the starter or ring gear again. Unfotunately
All of my shop manuels and tech bulletin books are at work. I will try to remember to look this up and post tomorrow ..... or maybe someone else can look it uo and post

[porschyard]

The original G-50 ring gear part # 950 116 143 01 were flat similar to 915 and 930.
The updated ring gear 950 116 143 05 had a extended 1.5 mm lip to aid in poor starter engagement and fixed 99% of the engagement problems.

For that last 1 % like yours you will need to measure the dimensions shown in TSB 8708 Starter motor/gear damage and you will most likely find it was not machined correctly from the factory, dimensions should be 115mm +- 0.2
I have only seen this problem of incorrect machining tolerances 3-4 times in the past 35 + years and it is very rare and mainly on the early 87’s.

You don’t have to disassemble the gearbox and any competent machine shop can handle this.
Please post the dimensions you come up for the mounting flange, just curious what it is and if this is actually your problem.

Richard
img]http://forums.pelicanparts.com/uploads26/IMG_30101717374476.jpg[/img]

[nospiners]

Once again , great info and help here. I will check dimensions and get back here. Thank you so much

[nospiners]

Well , here is the proof…

I,m sure no machine shop is open Sunday night , but tmro morning off i go..

THANK YOU ALL !!!

[917_Langheck]

As a possible alternative to machining I think there is an extended star gear for the hi-torque starter to address issues like this.

There are a couple of threads on starter throws and gear widths in the archives.

[nospiners]

Originally Posted by 917_Langheck

As a possible alternative to machining I think there is an extended star gear for the hi-torque starter to address issues like this.

There are a couple of threads on starter throws and gear widths in the archives.

Great info , i'll check on that too, Thank you !

[wgirardot]

Could it be that the starter is not disengaging when the motor starts running.

I had this problem, and replaced starter, ring gear, and ignition switch ( for good measure ).


Bill

[nospiners]

Originally Posted by wgirardot

Could it be that the starter is not disengaging when the motor starts running.

I had this problem, and replaced starter, ring gear, and ignition switch ( for good measure ).


Bill

I thought so too , but after the second starter and ring gear still failed , dropped the engine and run it on the check stand and was able to diagnose the problem clearly. Its
definitely the distance of the starter gear to the ring gear. That Porsche bulletin above applies to my tranny. Its off to the machine shop already , hopefully i'll have it back soon enough, they're very busy and not too happy taking on my issue..

[porschyard]

Bumping this to find out if you went the machining the starter flange route and did that cure your starter problems.

Richard

[AlBackus36]

Interesting. I had this same issue on my '87. Occasional grind and damage found on Bosch starter and ring gear. I attributed it to a worn starter/weak ground. I swapped to the high-torque starter with the existing ring gear as part of an electrical refresh project and it was solved for me. I later replaced the ring gear when things were a part for a clutch. I imagine now I was in the 1% and didn't have a ground problem. Curious to measure my case now.

[EC900]

Not fully related… If the Tech Bulletin doesn’t apply, it could be a previous owner-operator/operation issue.

I once bought a car from a senior gentleman who was quite hearing impaired. He explained he often held the ignition key too long after engine turned over and I should be aware of some trouble with starting.
The split second of grinding over the years chipped away quite a few teeth on the flywheel. The tooth damage was in sections so it would often start without any problem but occasionally hit on the flat spot.
2¢

[nospiners]

Originally Posted by porschyard

Bumping this to find out if you went the machining the starter flange route and did that cure your starter problems.

Richard

I actually did do that , just got the tranny back , it will go on the engine test stand soon and i will report back.

[porschyard]

Originally Posted by nospiners

I actually did do that , just got the tranny back , it will go on the engine test stand soon and i will report back.

I don’t think they sell the old style flat ring gear anymore but make sure you are using the late style with the 5mm extended width teeth and keep us posted.

Richard

[nospiners]

Well , finally done !! Shaving the 2mm off did the trick , i also used the newer ring gear and all good now , no more horrible grinding noises at engagement.. THANK YOU ALL !!!