View Poll Results: Have you experienced a broken distributor belt?
Yes
15
7.50%
No
185
92.50%
Voters: 200. You may not vote on this poll
How many have broken their distributor belt?
#32
Racer
Same here, Alex.
I plan to install a new belt on the spare DD more slowly taking measurements of the bearings for future reference. Usually, bearings have a number on the side of the races but these bearings might be too small?
Anyway, dimensions can also be used to find new ones. In the Spring, I'll go to Kaman Bearings in Trail and see if SKF, ***, Koyo or ? has something that will fit exactly. I suspect that they're just sealed single row ball bearings. Once we get the right part numbers, the mystery might be solved.
I can see how a frozen bearing will make the small tooth belt work so hard that it'll eventually either break or jump teeth. With 60k Miles (or 100k Kms) I believe that along with a new belt, the bearings should be changed for piece of mind.
I plan to install a new belt on the spare DD more slowly taking measurements of the bearings for future reference. Usually, bearings have a number on the side of the races but these bearings might be too small?
Anyway, dimensions can also be used to find new ones. In the Spring, I'll go to Kaman Bearings in Trail and see if SKF, ***, Koyo or ? has something that will fit exactly. I suspect that they're just sealed single row ball bearings. Once we get the right part numbers, the mystery might be solved.
I can see how a frozen bearing will make the small tooth belt work so hard that it'll eventually either break or jump teeth. With 60k Miles (or 100k Kms) I believe that along with a new belt, the bearings should be changed for piece of mind.
#34
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Replaced belts in my 993s even though still look good but like you said Steve I too had bad bearings in one of them .
here was the fix
used ball brg NSK 6201-08DDU, but there are SKF/NTN/*** equivalents.
Basically a double rubber sealed 6201 ball brg.
These brgs are the same dimensionally except for the ID wich is 0.5mm dia. larger.
Prepare the brgs in advance by wrapping 0.25mm thick shim stock of appropriate x-y dimension around the shaft, and apply a bit of retaining compound to the ID of the brg so that the shim/sleeve is glued to the ID of the brg.
You will need a blind brg removal tool to remove the olds brgs.
I think the brgs were around $15 ea.
Cheers Guy
here was the fix
used ball brg NSK 6201-08DDU, but there are SKF/NTN/*** equivalents.
Basically a double rubber sealed 6201 ball brg.
These brgs are the same dimensionally except for the ID wich is 0.5mm dia. larger.
Prepare the brgs in advance by wrapping 0.25mm thick shim stock of appropriate x-y dimension around the shaft, and apply a bit of retaining compound to the ID of the brg so that the shim/sleeve is glued to the ID of the brg.
You will need a blind brg removal tool to remove the olds brgs.
I think the brgs were around $15 ea.
Cheers Guy
Cheers,
Mike
#36
Rennlist Member
Usually, bearings have a number on the side of the races but these bearings might be too small?
Anyway, dimensions can also be used to find new ones. In the Spring, I'll go to Kaman Bearings in Trail and see if SKF, ***, Koyo or ? has something that will fit exactly. I suspect that they're just sealed single row ball bearings. Once we get the right part numbers, the mystery might be solved.
Anyway, dimensions can also be used to find new ones. In the Spring, I'll go to Kaman Bearings in Trail and see if SKF, ***, Koyo or ? has something that will fit exactly. I suspect that they're just sealed single row ball bearings. Once we get the right part numbers, the mystery might be solved.
Once I have the exact dimensions, I will have my co-worker check if they are available. He works with bearings in the tribology department; that is all he does...bearing failure analysis.
It has been said that they were specially made for Porsche/Bosch which I find hard to believe. Manufacturers usually take off-the-shelf bearings.
There is very little load on them considering their size and RPM (half engine speed). The belt will fail due to age more than wear in most 993 cases.
Same here. I will as a minimum check them.
By the way, the Bosch number for the distributor is: 0 207 503 004, other script under the part number is: PHFXZ 6x2
#38
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#39
Rennlist Member
I'll soon know.
Machining a collar would be a possibility as long as the wall thickness was say 1 mm. There is a 15 mm bearing with a 32 mm OD with thicknesses of 8 or 9 mm.
#41
Racer
Sounds good, Alex.
Small correction: The Bosch number is 0 237 503 004 and the Porsche ID number is 930.602.015.01 for the dual distributor. The tooth belt is 930.602.134.00 and available from Porsche AFAIK.
The right size bearing would be best but, we'll see................................
Small correction: The Bosch number is 0 237 503 004 and the Porsche ID number is 930.602.015.01 for the dual distributor. The tooth belt is 930.602.134.00 and available from Porsche AFAIK.
The right size bearing would be best but, we'll see................................
#42
Rennlist Member
The reason the bearings crap out was moisture got in and the bearings had lots of rust ( maybe from when I power wash the engine while it was out ? ) Notice it only when replacing belt , there was no indication beforehand I guess just lucky that I decided to do the distributor maintenance when I did .
As far as the fix , the sleeve ( collar ) it was cemented to the shaft it is not going anywhere . I`ve done 1.5 season approx . 10k km and all is well .
Cheers Guy
As far as the fix , the sleeve ( collar ) it was cemented to the shaft it is not going anywhere . I`ve done 1.5 season approx . 10k km and all is well .
Cheers Guy
#43
#44
When I enquired at a p-car specialist about a replacement belt he described broken belts on a 993 as rare and suggested a complete new unit in a couple of years as the bearings might be starting to wear and new caps would also be good.
He could not source the non standard size bearings used by Bosch.
I found some information on a couple of German Porsche forums and the bearings were listed as INA-Schaeffler Germany 7201 BE 2RS (AH01 F0329, K0807, F0831, special order production numbers) The bore size is 12.45mm, 32mm OD and 10mm deep.
Not available from Bosch and Schaeffler will not sell them either.
This is what INA Schaeffler do have available 7201-B-2RS-TVP angular contact ball bearings.
http://medias.schaeffler.com/medias/...P;bF89aeEIqQ15
I know this size does not tally with what Guy has posted so will have to wait for Alex to report back in the true spirit of the Rennlist with his dimensions and a possible fix that might save us DIYers money. (Unless he develops a commercial interest!)
#45
Racer
Interesting.
Are the OEM bearings actually angular contact bearings?
Or just regular ball bearings?
Angular contacts are used when, aside from a radial load, an axial load factor is present like on most wheel bearings which are usually double-row as well.
If the distributor bearings are angular contact, they may have to be installed correctly to respect the axial load-factor.
Are the OEM bearings actually angular contact bearings?
Or just regular ball bearings?
Angular contacts are used when, aside from a radial load, an axial load factor is present like on most wheel bearings which are usually double-row as well.
If the distributor bearings are angular contact, they may have to be installed correctly to respect the axial load-factor.
Last edited by Gunter; 01-19-2011 at 12:09 PM.