PT81PlymouthPickup Posted June 27, 2020 Report Share Posted June 27, 2020 In my struggles to figure why my engine runs roughly at partially open throttle and with help from searching on P15d24, I have discovered that the distributor shaft has more clearance than feels right. I measured with a dial indicator and it's wiggling at .012". That seems excessive? Anyhow, I'm not certain if this is the culprit to my engine falter at higher rpm, but I want to fix it regardless and just maybe I'll be lucky? According to the 1947 edition Autolite service parts catalog https://www.thecj2apage.com/storage/47_autolite_service.pdf my 1939 Plymouth PT81 should have had a IGS-4103A-1 or an IGS-4103B-1 but the distributor that's in it is a IGS-4003-1 which is an earlier one listed for 1935-36 Dodge and Plymouth cars. Unfortunately, I have no idea what my engine came out of? The numbers on the block were removed. I'm guessing that it may have been an earlier engine that was re-manufactured? Perhaps that's why the earlier distributor? My conundrum is what to do now? Install new bushings? Try to locate another distributor in better condition? Which one? Does it matter? I was thinking of installing a Pertronix unit or Langdon's mini HEI? I like the idea of not having to service points and getting rid of ballast resistor. Perhaps this is the time, but the more I read about those options the more confused I become. Opinions and advice welcomed and appreciated. Quote Link to comment Share on other sites More sharing options...
The Oil Soup Posted June 28, 2020 Report Share Posted June 28, 2020 Perhaps that was an industrial engine, most I've seen have casting dates on the head and or driver's side of the block. Industrial engines generally lack a vaccum advance so maybe that is why it may have the incorrect dizzy. Quote Link to comment Share on other sites More sharing options...
Worden18 Posted June 29, 2020 Report Share Posted June 29, 2020 I'd go with the electronic ignition option. Quote Link to comment Share on other sites More sharing options...
PT81PlymouthPickup Posted June 29, 2020 Author Report Share Posted June 29, 2020 15 hours ago, The Oil Soup said: Perhaps that was an industrial engine, most I've seen have casting dates on the head and or driver's side of the block. Industrial engines generally lack a vaccum advance so maybe that is why it may have the incorrect dizzy. Yes, I think that might be the most likely possibility. I also was told years ago that some of the professional engine re-builders would remove the numbers? Hard to say! I just discovered that the breaker plate in my distributor is the correct one for my 1939 truck, but the distributor housing is listed for earlier (1935-36 cars). Obviously, some of the parts interchange, but not being very knowledgeable on these distributors, I have no idea how important it is to have the correct distributor for the engine. I'm uncertain as what might be my best path? Get the correct one for my truck? Rebuild the one I have? Quote Link to comment Share on other sites More sharing options...
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