Gunter

This time I took a closer look and here are some measurements:

Primary shaft is 12.44 mm on top and 11.99 on the bottom.
Secondary shaft is also 12.44 mm both ends.

Three bearings (1 on top of primary and 2 on secondary top & bottom) are the same: 32 mm OD, 12.45 mm ID, about 10 mm wide are a special order NLA.

The bottom bearing on the primary shaft is a dual set-up with a needle bearing for radial and a ball bearing for axial loads 22 mm OD & 12 mm ID about 25 mm total width.
Both bottom bearings on the primary are open once the shaft is removed and can be checked and lubed.
The other 3 bearings are sealed and almost impossible to clean and lubed unless one has good magnification and special picking tools. Someone posted that a 6201 bearing can be used but I don’t see how since the ID of 12 mm cannot fit over the shaft being 12.44 mm.
One would have to find bearings with ID 13 mm, OD 32 mm, about 10 mm wide and use shim stock to make up the difference of 0.5 mm on the ID.
But, there are no 32 x 13 x 10 bearings.
And the combination bottom-bearing on the primary shaft is impossible to find. If those bearings are worn out, one has to have the distributor professionally rebuild i.e. Steve Weiner or Bosch or?

One could try and replace the needle bearing on the primary with an equivalent but to do that one has to remove the small axial thrust bearing first; pretty tricky.

IXLR8

Günter,

I just assembled my distributor after a complete overhaul minus bearings.

I did not have any of my bearings out since they are all fine.

Considering the side load placed on them by the Belleville washer, I am sure they are not a ball bearing but a contact angular bearing. Having one apart would confirm that.

As for the lower bearing on the primary shaft, I doubt that one would go very often.

As for the availability of the bearing, I would just take a 32x12x10 and grind the inside radius to size; all it needs is 0.22mm taken off. They may be impossible to find...till someone makes one at home.

Gunter

I don't think the 3 identical bearings (12.45 ID, 32 OD) are angular contact because the axial load is taken care of by the bottom bearing on the heavier primary shaft. Any potential axial play is eliminated by compressing the spring washers during assembly. When the gear is on the primary and the circlip on the secondary, all axial play is gone. The 11.99 mm diameter step on the bottom of the primary shaft is there to eliminate axial play when both bearings are compressed by the spring washer.

Good luck in removing 0.22 mm from the ID of an inner race of a small bearing which is hardened; a lathe won't do it and grinding would still rquire a way to grip the inner race so it won't turn on you.

Gunter

Good theory re removing the inner race and grind out the bore.
This old ME thinks that dismantling a small bearing like this will most likely damage the seals and the cage. Then there is the issue of centering the inner race on a lace to run true. The inner bore is only 12.00 mm (about 1/2")
Paying someone to dismantle the bearing and most likely destroy it and grinding off 0.22 mm from the bore, then re-assembling the bearing with cage and seals intact is highly improbable.
It's not worth it considering that Bosch in Karlsruhe, DEU, will rebuild the whole distributor with new original bearings.

Or have Steve do it. With some special tools and magnification, the seals can be carefully removed, bearing cleaned and lubed and re-assembled if the ***** and races are still good.

IXLR8

Maybe, but in any case, whatever axial load is at the bottom bearing is equal to the axial load at the top bearing.

Heavier primary shaft? Both primary and secondary shafts have the same OD except at the bottom bearing of the primary shaft where it is 12.04 mm.


Not just play is taken up; the bearings are pre-loaded and in my opinion, more than they have to be.

I had to use my drill press to overcome the tension in the Belleville washer so as to get the hole aligned in the gear with that in the shaft before sliding the pin in.


Günter, never give up. The BMW service manual and parts list indicated that the Valeo starter motor for my motorcycle was not rebuildable. At that time, they wanted just over $830. Yeah right, not rebuildable, sure anything you say, BMW. I rebuild it and wrote up a DIY since nobody at the time had rebuilt one.

If I had to, I'd sooner get one from the supplier where the complete distributor is refinished than getting one rebuilt. In a PM from Steve recently, the bearings are $140 each plus $220 for the rebuild plus parts. So count on at least $650 for a partially overhauled distributor, and at that, it does not include a new sender plate.

Anyway, at my mileage I am not going to worry about the bearings as they are smooth and quiet (still greased). I will experiment with increasing the ID of a sample bearing though.

Steve Weiner-Rennsport Systems

Hi Alex,

FWIW,....after rebuilding well over 300 distributors since 1995, I've yet to see a faulty Hall-Effect assembly. Remember, thats not a trigger; its only for cam position reference with that full-sequential Motronic FI system.

I've seen some real ugly ones along the way, without a doubt, but they all work unless someone was ham-fisted with the connectors.

When we are done rebuilding them, I think they are better than new since we re-pack ALL the bearings (when needed) with a much better high-temp grease than the bearing manufacturer used.

IXLR8

Hi Steve,

Do you mean that you re-pack the existing/original bearings? Since they are a sealed bearing, do you remove the bearings, remove the seals, wash them out, and repack them before installing the seals again?

Steve Weiner-Rennsport Systems

Hi Alex,

Yes. If we find one that feels dry but otherwise smooth, we remove the bearing(s), carefully remove the seal, clean out the old grease and re-pack it with a better synthetic hi-temp product than what they came with. In many cases, they respond very nicely to this maintenance regimen and feel just like a new one.

When we find a bearing thats feels rough, those are simply replaced as needed.

IXLR8

OK, since you've had them out and apart, are they a deep groove ball bearing or an angular contact bearing or another type.

I found the axial load placed on them unnecessarily high with that Belleville washer and number of shims installed. A shim on each shaft could be left out and they would still be loaded.

Steve Weiner-Rennsport Systems

Standard deep groove ball bearings.

Gunter

Please, check again.

The original bearings were angular contact ball bearings 7201 BE 2RS special order from INA-Schaeffler Germany.
Angular contact because there is an axial load from the spring washers.
These 40 deg angulars would have to be installed the right way to enable correct function.

Deep groove might work but.........................I'm sure a batch of ??? angular contacts 12.45 x 32 x 10 could be ordered from some manufacturer in China like Best Bearing Co. but that would only work for someone who does a lot of work on these duals.

But there is also the needle- and thrust bearing combination on the bottom of the primary shaft. All in all, not easy to find replacements.

Best.

nine9six

Maybe Im missing something...All in stock where, Diddi?

Never mind...Found in the correct link, here...Just go back a page.
https://rennlist.com/forums/993-foru...earings-4.html