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Dual Distributor Rebuild Durability

Old 01-09-2019, 11:32 AM
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pp000830
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Default Dual Distributor Rebuild Durability

I am looking for a little information from 993 Rennlist members on the durability of dual distributor rebuilds, something that our community may benefit from.
If you have had your distributor rebuilt please answer the below questions:
  • Was your distributor rebuilt due to a functional failure such as the belt breaking? Y/N
  • Did your rebuilt distributor fail for a 2nd time subsequently to the rebuild? Y/N
  • For approximately how many miles have you been running on your current rebuilt distributor?
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Old 01-09-2019, 11:33 AM
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  • Was your distributor rebuilt due to a functional failure such as the belt breaking? Y/N
  • N
  • Did your rebuilt distributor fail for a 2nd time subsequently to the rebuild? Y/N
  • N
  • For approximately how many miles have you been running on your current rebuilt distributor?
  • 5000
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Old 01-09-2019, 01:42 PM
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rg0115
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Here you go. I had mine rebuilt as preventative maintenance it did not fail but wasn't going to find out what could happen.
  • Was your distributor rebuilt due to a functional failure such as the belt breaking? N
  • Did your rebuilt distributor fail for a 2nd time subsequently to the rebuild? N
  • For approximately how many miles have you been running on your current rebuilt distributor? 7,000
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Old 01-09-2019, 05:52 PM
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IXLR8
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No failure to the original belt, but due to Rennlist phobia, I replaced the belt and checked the bearings. This was back in 2011 when bearings weren't readily available.

Original belt was 16 years old with about 42K miles. The belt was fine once I had it off for inspection. With the vent kit, I highly doubt the belt would fail at that age and mileage. The belts that failed in the ones I have rebuilt for friends and members usually had binding or seized bearing(s) due to rust.
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Old 01-09-2019, 06:15 PM
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IainM
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Is that why you should put a drop of oil on the felt pad under the rotor cap?
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Old 01-09-2019, 06:32 PM
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Originally Posted by IXLR8 View Post
No failure to the original belt, but due to Rennlist phobia, I replaced the belt and checked the bearings. This was back in 2011 when bearings weren't readily available.

Original belt was 16 years old with about 42K miles. The belt was fine once I had it off for inspection. With the vent kit, I highly doubt the belt would fail at that age and mileage. The belts that failed in the ones I have rebuilt for friends and members usually had binding or seized bearing(s) due to rust.
So correct me if I am wrong, there is a bearing at the base of the housing below each rotor shaft and a bushing near the end gear that is also called a bearing by some.
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Old 01-09-2019, 06:45 PM
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Churchill
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Had my distributor rebuilt by Hank Cohn 10 years/40K miles ago as preventative maintenance while I had the engine out for a clutch job. Would expect the bearings to be 100K+ mile maintenance items.
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Old 01-09-2019, 07:34 PM
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IXLR8
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Originally Posted by pp000830 View Post
So correct me if I am wrong, there is a bearing at the base of the housing below each rotor shaft and a bushing near the end gear that is also called a bearing by some.
There are a total of three 7201 bearings and one NX 12-XL needle/ball bearing. The latter is not absolutely necessary since it is splashed by oil, but it is cheap, so I replace it for a full rebuild.

The driven shaft is actually the secondary shaft and it takes one 7201 bearing and one NX 12-XL bearing. The NX 12-XL bearing sits right next to the driven gear. The 7201 on this shaft from what I recall never seems to go.

The primary shaft has two 7201 bearings. It is the shorter shaft of the two. These are the bearings that usually fail due to rust.

Andy, it would be best to see some pics and I have some on my photo site of three or four dual distributors of many I have done for friends, locals and a few RL members.

My dual distributor is the one with the slide hammer. My belt showed no signs of fraying or cracking. Expected at the low mileage.

Have a look at Bill's Dual Distributor, photo 26. It is showing early signs of rusting and it would only be a matter of time till the bearing failed.
When you look at the orientation of the dual distributor, the primary shaft is angled down which is why water tends to collect at that bearing for whatever reason (heavy rainfall, washes or power washes, etc)

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Last edited by IXLR8; 01-09-2019 at 09:19 PM.
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Old 01-09-2019, 07:40 PM
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crw
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My distributor belt showed some minimal wear at 30K miles
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Old 01-09-2019, 11:13 PM
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Steve wiener rebuilt mine. Whole thing was a hot mess. He ended up replacing nearly everything. Haven't had a single issue with it since. I left this rebuild to the pro.
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Old 01-10-2019, 12:17 AM
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mike cap
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The one in my car now is a Bosch remanufactured unit. 2,000 miles and no issues. My original had some sketchy bearings at 42,000 miles so to avoid the downtime we put in the reman unit. My original (now pickeled and put away) was rebuilt by a distributor master someplace in a North America who shall remain anonymous.

Last edited by mike cap; 01-10-2019 at 01:16 AM.
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Old 01-10-2019, 10:23 AM
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pp000830
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Originally Posted by IainM View Post
Is that why you should put a drop of oil on the felt pad under the rotor cap?

I put a little motor oil on the pad in the shaft the rotor slides on to as my father taught me on his cars years ago. This was back when cars had points and a coffee can of used points resided in the trunk of his Buick for reuse.
In Northern Ohio and now Virginia it seems the small amount of oil applied tended to coat things below the plastic donut-shaped shield on the rotor shaft and may have contributed to the total lack of corrosion on the internal parts of the distributor assembly. Although only a theory, could the lack of lubrication at cap and rotor changes be the root cause of corrosion-related distributor bearing failure for others, who knows?
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Old 01-10-2019, 10:36 AM
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Rebuilt mine at 88,000 miles. Belt was hard and beginning to crack. Was able to get the three 7201 bearing, so I did them. One of those bearings was a little rusty.
30,000 miles since, no issues.
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Old 01-10-2019, 03:58 PM
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This is likely answered elsewhere so forgive me, but how easy is it to get these bearings now? A standard 7201 bearing is 12mm ID, and from what I recall we need a modified 7201 with a 12.45mm ID.

Last I looked it appeared *** bearing was the only supplier of a bearing with this ID (7201-BE-2RS-AH01). Is this still the case? Last I looked these were only available from a few places at near $75/bearing.
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Old 01-11-2019, 01:27 AM
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IXLR8
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Originally Posted by Top-Gun View Post
Last I looked it appeared *** bearing was the only supplier of a bearing with this ID (7201-BE-2RS-AH01). Is this still the case? Last I looked these were only available from a few places at near $75/bearing.
As far as I know, yes, but then I haven't done any further searches since 2011. Back then, one rebuilder was charging $140 a bearing. The bearings are up to Ç62 a bearing now from Germany. Not the end of the world for a long term peace of mind.

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