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As you know I run a 501" BBF in a flatbottom boat. This entails lots of continious high rpm running. Twice in two years the roll pin holding the cam gear to the distributor shaft has broken. The distributor is a dual point Mallory of 60's vintage. Except for the triggering mechanism, the new ones look the same.
I gather from discussions this may be a weak area of the Mallory distributor although other makes look similar.
1. Has anybody else experienced this problem?
2. Changing distributors is not a possibility as I
need the Mallory small cap for clearance purposes.
3. Two potential solutions are to replace the 1/8"
roll pin with a 5/32" pin. To ccomodate the existing hole in the shaft must be drilled larger. Any problems with weakening the shaft?
4. Replace the existing 1/8' pin with a spring wound pin which is supposed to be stronger?
Any advice would be welcome.
Thanks
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67f100
(no login)
209.162.57.54 Distributor gear pin breaking...
No score for this post July 14 2001, 4:19 PM
Usually this is caused by using a HV oil pump, and by also using heavier oil. Going to a larger pin would help the gear pin breakage, and use the hardest pin you can find. I don't know what oil weight you are using, but you might want to re-evaluate that. Too heavy a viscosity of oil can cause bearing failure, because of the lack of flowability.
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gregaust
(no login)
203.17.162.31 mallory rollpin
No score for this post July 14 2001, 9:55 PM
I have had the same problem with a couple mallory twin point dist's over the years.One i repaired just a couple weeks ago i drilled the gear+shaft to 5/32.The previous one i drilled to 3/16 and fitted an original ford roll pin.I don't think drilling the shaft would make it any weaker as the original ford dist's have a 3/16 pin stock .I remember seeing an article a few years ago that adressed this prob + suggested the larger size pin.
HOPE THIS HELPS.
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Bob MacD
(no login)
24.112.158.243 Thanks for the ideas
No score for this post July 14 2001, 11:27 PM
Yes I am using a HV pump and 15-50W synthetic oil. I will drill out the hole to 5/32" and use a coiled pin for strength.
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Ken
(no login)
165.154.190.1 Easy fix
No score for this post December 13 2001, 2:04 PM
move up the shaft and 90 degrees to the existing pin, drill a second hole and put in a second pin. Go as high as yopu can for seperation. Haven't broken a pin in years.
I gather from discussions this may be a weak area of the Mallory distributor although other makes look similar.
1. Has anybody else experienced this problem?
2. Changing distributors is not a possibility as I
need the Mallory small cap for clearance purposes.
3. Two potential solutions are to replace the 1/8"
roll pin with a 5/32" pin. To ccomodate the existing hole in the shaft must be drilled larger. Any problems with weakening the shaft?
4. Replace the existing 1/8' pin with a spring wound pin which is supposed to be stronger?
Any advice would be welcome.
Thanks
Score 1 2 3 4 5 (5=Excellent) Edit Message Delete Message Lock Thread Respond to this message
Author Reply
67f100
(no login)
209.162.57.54 Distributor gear pin breaking...
No score for this post July 14 2001, 4:19 PM
Usually this is caused by using a HV oil pump, and by also using heavier oil. Going to a larger pin would help the gear pin breakage, and use the hardest pin you can find. I don't know what oil weight you are using, but you might want to re-evaluate that. Too heavy a viscosity of oil can cause bearing failure, because of the lack of flowability.
Score 1 2 3 4 5 (5=Excellent) Edit Message Delete Message Lock Thread Respond to this message
gregaust
(no login)
203.17.162.31 mallory rollpin
No score for this post July 14 2001, 9:55 PM
I have had the same problem with a couple mallory twin point dist's over the years.One i repaired just a couple weeks ago i drilled the gear+shaft to 5/32.The previous one i drilled to 3/16 and fitted an original ford roll pin.I don't think drilling the shaft would make it any weaker as the original ford dist's have a 3/16 pin stock .I remember seeing an article a few years ago that adressed this prob + suggested the larger size pin.
HOPE THIS HELPS.
Score 1 2 3 4 5 (5=Excellent) Edit Message Delete Message Lock Thread Respond to this message
Bob MacD
(no login)
24.112.158.243 Thanks for the ideas
No score for this post July 14 2001, 11:27 PM
Yes I am using a HV pump and 15-50W synthetic oil. I will drill out the hole to 5/32" and use a coiled pin for strength.
Score 1 2 3 4 5 (5=Excellent) Edit Message Delete Message Lock Thread Respond to this message
Ken
(no login)
165.154.190.1 Easy fix
No score for this post December 13 2001, 2:04 PM
move up the shaft and 90 degrees to the existing pin, drill a second hole and put in a second pin. Go as high as yopu can for seperation. Haven't broken a pin in years.
