Pin on Distributor keeps breaking at gear

[Michael C Henry]

If the hole is worn in the original distributer gear the gear should be replaced. MSD uses true roll pin rather than spring pins . A little tougher. I/8" x 3/4" as I remember. Got mine through Summit. Drilling for a larger pin weakens the shaft. The oil pump drag is usually the problem. Thick oil, high volumes, and or high releif presure. I was worned that I should not get carried away with RPM until the engine oil temperture was showing at least 140° Think of that pin as a fuse, a built in weak point. It will only take so much. A larger for pin hole will weaken the shaft and or move the damage further up the line like twisting the drive shaft, if the oil pump stalls or such. They make a FE truck pump with a larger hex drive 5/16" as to original 1/4". And they make better material drive shafts with 5/16" hex shaft with 1/4 tip to fit the car distributer shaft tip. As it was shown to me most wear of the oil pump drive line was at the female hex socket in the oil pump end rather than the distributer. Under normal cercumstances, the original 1/4" hex drive and 1/8" pin worked just fine, but add higher volume oil pumps at higher releif presurses the throw in cold oil and something has to give. But when the oil pump is stalled the the distributer drive pin breaks the distributer stops , the engine ignition imediatly stops and the engine coast to a stop. If not at high RPMs usually no damage and is caused and it only takes another pin and about an hour to repair.
It has been mentioned in past postings on this subject that the shaft outside and gear inside measurments may varry causung anything from a rattle to a press fit.