Gunter

As mentioned by others, Bosch will not sell the special bearings as confirmed now with this reply:

Bei den Kugellagern zu dem Tandem-Zuendverteiler handelte es sich
um eine Spezialanfertigung von Fa. INA. Leider können wir Ihnen diese
jedoch nicht zum Kauf anbieten.

Sie haben jedoch die Möglichkeit einen Austausch Zuendverteiler zu erwerben.
Bestellnummer 0 986 237 900.

Bitte wenden Sie sich fuer Preis- bzw- Lieferauskunfte an den naechstgelegenen
Bosch Car Service. Anschriften siehe unter
http://www.bosch.ca/content/language1/html/2744.htm

Mit freundlichen Grüßen / Best regards

Jürgen Gräber

Robert Bosch GmbH
Automotive Aftermarket
Sales Europe Central
Kundenberatung (AA/SEC3)
Postfach 41 09 60
76225 Karlsruhe
GERMANY

Short translation:

Specially made for Bosch by INA, not available to the public.
Suggests to order a rebuilt distributor from Bosch.

So, we'll have to find similar bearings and shim the inside dia. for a good fit and hope for the best.
As I suspected, the bearings are designed for side-load but I think regular ball- or needle bearings may work. (At least for a while)

IXLR8

Why not, I'll just buy a new car because I have a flat tire, or a new engine because I have a bad valve.

Their loss!

They could sell me a 5 cent cap that covers the bottom bearing and shaft of the secondary distributor for $10. Instead, I found an identical looking frost plug for $1.75 tax included. Hey Bosch...

When the time comes, I'll be using a 12 x 32 x 10 angular contact bearing, for example, an INA 7201-B-2RS-TVP.

At an ID of 12 mm, all I have to do is open that up in radius by 0.223 mm. Some angular contact bearings come apart which means I can hold the race in my lathe and grind the ID as necessary. I might just buy one for the fun of it and give it a try.

tctung

Both belt and bearing were replaced after 120,000 km (about 75,000 miles) on recommendation of the shop last year. Old belt looked slightly dry but seemed still good for some extra miles. I was also surprised that such a tiny stripe of rubber could last 15 years.

Doink

112,000 miles, and still on original distributor belt. I have owned the car for 9 years, 80,000 miles.

I do not know of any owner in the UK who has had a 993 distributor belt break. Both my independent specialist, and Porsche dealer, have not advised replacement, and both are very knowledgeable I would say.

Since reading this thread, I'm now thinking about replacing the belt for the first time.

Join Rennlist, and scare the pants off yourself !

IXLR8

Same here on a belt that had ~72K kms or ~45K miles. I'm glad I'm changing it though due to age. Plus I get to inspect the bearings and grease them while they are still good and the distributor get a thorough clean and greasing where necessary.

Its only spinning a secondary distributor shaft, so unless the bearings are seizing, there is hardly any load on it.

Gunter

Greasing the bearings would require Micro Surgery with major magnifications to carefully remove the seal, inject some lube and then replace the seal without damage.

May work or not.

But, new grease may not renew the bearing if the races or the tiny ***** have wear.

When I dismantle my spare distributor and need new bearings, I think I'll go with a new bearing 32 mm O.D. 10 mm wide and 13 mm I.D. and simply shim with one layer of 0.5 mm shim stock (Or SAE equivalent) around the shaft cemented with Loctite.

IXLR8

The seals do not have to be removed. One can easily slip the tip of a needle past the edge and inject grease.

BUT, sealed bearings come with a pre-determined amount of grease and adding more is actually detrimental to bearing life. I'd be adding some if they look low on the amount of grease.

If one side of the bearing is open, then pack the bearing as much as you want. I have to check if the insides of the bearings on the secondary shaft are open or sealed.

At that point, it is too late, which is why I checked mine despite the low mileage.

amfp

Severely frayed after inspection ~ 60K miles. Of course it is not mileage, but many years of rubber degrading.

Steve Weiner-Rennsport Systems

FWIW,.....

The belts are under little stress unless the bearings dry out. Its the ozone buildups that deteriorate the rubber over time.

Many of these bearings came with VERY little grease in them and in fact, they even do not contain a high-temp grease (more suitable for the operating conditions). When we find that the bearings are dry after cleaning and examination, sometimes we can carefully remove the seals, clean the bearings, and re-grease with a better high-temp product thats superior to what they came with. One can really feel the difference.

In some cases, the bearings cannot be rehabilitated and we must replace them.

The key issue here is the lack of an effective warning system that alerts the driver to a broken belt (or seized bearings). Without a regular maintenance program of belt replacement and inspection, one is risking some very expensive consequences.

IXLR8

So they are available. Who from?

Steve Weiner-Rennsport Systems

It took me 3 solid years to dig that out so I'm unable to share that.

I do however, offer them as part of a distributor rebuild.

IXLR8

I'm usually on forums to share information but then I don't run a business. Nahhh, even if I did.

Renaud Bizet

Hi Steve,

What is the cost to ship you a distributor for a rebuild?

Thank You

Renaud

IXLR8

And does that cost include 3 new bearings?

Steve Weiner-Rennsport Systems

PM sent.