What are your guys' thought on welding a distributor shaft. Say taking two pieces of a shaft and welding them together. As long as it's chamfered, straight, and welded correctly, do you guys see any presented problems in doing this? Besides the high RPM's and centripetal force applied to the shaft, I don't see any major loads that could be applied that could cause any issues?
I had a feeling that would be the first question asked. Just wondering, lets say if you wanted to fix a broken shaft and length wasn't an issue. Or if you wanted to make a custom shaft to fit in a different oil pump and didn't want to machine a whole custom piece. Just wanted to see what your guys thoughts were on the subject.
Theoretically, properly done welds are as strong as the parent metal. That said, though, I would want the weld in the "no load" area of the shaft...meaning not in the section between the gear driven by the cam and the oil pump drive end. There is much less torque required to drive the distributor than the oil pump. no point is stressing the weld more than necessary. Other than that caution....why not?
More screwing around than machining a new one from scratch! Have you ever welded a shaft together and gotten it straight enough to use in a distributor? It ain't easy!
Thanks for the input guys. That's what I was thinking as well Wolfcreek about the straightness of the shaft after welding. At that high of rpm the slightest deviation between the two shafts welded together can be pretty big.
I tend to agree...depends somewhat on the particulars of the shaft, but certainly worth consideration.
We do it quite a bit. Drill one side of the shaft and machine a spud on the other side . Press the two together and either pin or weld the shaft in a lathe. Some distributors dont have any torque on them while others drive the oil pump etc...The ones with no torque we just drill-bung and pin with rol pin... I also like the way Hot Heads extend the shaft using a slip over tubing with a pin as well...
Good thoughts. The one I have has no load. Jus a tang in the pump itself. Pump gear driven by cam gear. So GMC, for no load distributor, you just notch each shaft, drill through both, pin and weld?
You will NEVER get it straight enough to run. Unless its a Dusenburg distributor you should be able to find another in Hemmings.
In the case of a distributor that drives the oil pump, you could use a steel rivet, correct? When I added a Pertronix to my GMC V6, I had to shim the gear and re-swage a new universal head rivet in my vise. Works like a champ. I would think the rivet is best, since it has a solid cross-section as opposed to a roll pin.
If you look at the drive gears on most factory distributors, and see what holds that gear on the shaft, and consider it also drives the oil pump, then there's no reason a good weld done properly wont be as strong or better. My concern would not be whether the weld is strong enough, but just ensuring the shaft is perfectly true when it's done.
I love it when someone says it cant be done... two posts after a pro dist. builder says he does it all the time.
I would look at using a piece of repacement steel, welding the top from the donor onto it and machining the lower to accept the gear,maybe I'm not picturing the distributor your working on well. I would not try to weld the middle of the shaft. I'm sure it can be done with enough equipment to ensure its straight, but its not typical garage equipment. Do a search on 409 chevy distributors, I've seen big block chevy distributors modified for shorter 409 applications
You guys are hilarious. I thought the same thing when I saw it cannot be done. Thought, I think I could make it work! I'll have to do some thinking on ways I can make sure it's true when welded. Sounds like this will be the toughest obstacle. The distributor shaft isn't real long, maybe if it's welded at the lowest point possible there would be less of an issue in deflection. Agreed looking at setup that loads shouldn't be an issue. No major force on distributor itself.
Make the the stub as GMC Bubba suggests, hole and stub. Make the new end oversize. When all the welding is finished, machine the new end to finish diameter. Ago
This is what I would do. Face off both ends in a lathe. Next drill a hole in each end to accept a pin, then chamfer each end. Press the ends together with the pin inside and TIG weld. Place the shaft in the lathe and straighten, using a dial indicator and a dead blow hammer. Of course it can be done but why? Sounds like a lot of work for a $20 part.
Ten years ago one of the popular mods to 2.3 Ford Turbo engines was to use a Chrysler distributor and Ford distributor and make a distributor that works with the 2.3 Ford. That allowed the use of the Chrysler EEC from the Turbo Chrysler cars. The advantange was programmable tuning before stand alone engine management became availabe at reasonable pricing. That isn't any different from what the OP asked, except the application was for Off Topic Engines.
It would be welding a shaft tang off one distributor to a different distributors shaft. Kind of an adapter. The tang needed is a larger diameter than the distributor shafts diameter. So it needs some growth. Smaller diameter just slips out of the pump.
That was my thought exactly before I read his post about doing it on a regular basis. It might not be the cost of having a machine shop do the work if you don't have access to a lathe or have a buddy who can do it for you though. That half hour it takes to do it might cost some serious $$$ at a machine shop.
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