Distributor Lower shaft

Robbie1

Robbie1

Junior Member
Hey guys! I'm trying to sort out my distributor. It was running good when disassembled, but why not make it right, right? I'm amazed on how vague the Mechanics Handbook is. There is about 1/4 inch play on the shaft (up and down) and a little wiggle on the lower side to side. Do I need to drill out the pin holding the upper shaft to the lower? Does it punch out? Most videos I see don't even show that these shafts are pinned together.I have a new upped shaft that's drilled for oil. I'm waiting on new bushings which will be another step. I assume now I will need the lower shaft ( this one is pitted ).

Thanks for your help!
 

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Yes to fix the play you have to take the pin out. Usually they aren't in there that bad if it was recently running. You can take a punch and hammer them out most of the time. If not, I just split the sleeve or cut the shaft flush with the distributor.

To correct for endplay, you shim it with washers until it turns freely but has virtually no endplay.
 
One area of wear is the channel in the housing the upper plate slides in. Also, the upper plate has ears that wear. Cupping the ears with a metal punch, and lubricating with dielectric grease, or even vasoline, can help. Or fitting a different upper plate.
Also another improvement is shrinking the
Center hole of the upper plate by preening it and filing the hole round.
Both areas of wear can affect the point gap variation.
Explaining that is above my pay grade.
I am impressed with your ambition, and hope to learn how you proceed.
Learn by doing is the best teacher.
 
Bob, My take on it is that although wear in the upper plate is a bad thing, any play is unnoticeable once installed with the plate spring pushing on it. Of course you don't want it to run thin either but I have never seen that happen before.
 
I think the replacement top plate could have been thinner, or the castings were varied, I don't remember anyone other than Tom Westenberg (sp) lubricating the grooves.
Several castings were worn, I did the modifications.
Never had my hands on a NOS distributor, just well broken in ones.
 
OK. I punched out the pin and ta da.....nothing. Still couldn't get them apart. I went with option 2. I took a hack saw and cut it in two. I made sure there were no burs on the upper shaft before pulling it out. I cleaned it out to the point of making my hands hurt. I installed the new (drilled) upper shaft. It was tight. there is no side motion to it at all. I've already ordered the lower shaft and bushings. SO...Do I try and change out the bushings when they get in or go with what I have (when lower shaft arrives)? A part of me says change it! It will all be new! Another part of me knows my luck, combined with enough skill to get me in trouble, and I end up cracking the housing installing new bushings.
 
If it is already tight, leave it alone. You might have to ream or hone it already. Put some oil on the new shaft and see how it turns.
 
New bushings will have to be reamed. I only change them if wear is excessive. The new shaft sleeve can come with a steel pin or a roll pin. I use the roll pin since there is no torque pressure on the sleeve.

I renewed my distributor recently and found that the fiber washer had fallen apart and the pieces slipped out. Due to that, I didn't use the fiber washer. I just used the steel shims. I ended up having to remove the valve cover and replace the oil pump & distributor drive. The old OEM stuff was all worn out. That area between the drive and the distributor is a corrosion point due to constant build up of condense in there. This makes the lower distributor drive shaft stick to the upper shaft and sleeve. I sprayed mine with LPS 3 corrosion preventative before putting it all back in.
 
I had to replace my distributor due to a cracked casting around the upper bushing. That distributor had a one-piece shaft. The replacement distributor had a drilled shaft, so I had to fit a new lower shaft. When I tried to fit the new lower shaft to it I found that it bound inside the sleeve that fits the upper shaft to the lower shaft (the sleeve that OP shows being held in by the pin). Likely due to a very slight mis-alignment of the offset of the slot. The solution I came up with was to take about 0.010" off the lower shaft in a lathe, then it fit into the sleeve just fine.

So with some luck the issue with OP's distributor will be plug-and-play. But that's not guaranteed.

JayJay
 
I suggest going with a new stainless steel lower shaft. Regarding the bushing reaming, I took a piece of round barstock, hacksawed a slot in it, then placed some fine sandpaper in the slot. Using my drill, I "honed" out the bushings until the shaft would just fit. Poor man's hone. Worked for me.
 
I’ve done the poor man’s hone, then use the old or new shaft and spin it in the bushings to burnish the bushings.
 
Is there a demand for Zenith Carburetors that need to be rebuilt, or would I be money ahead to rebuild them myself and then sell them?

Bill
 
imacrazy said:
Is there a demand for Zenith Carburetors that need to be rebuilt, or would I be money ahead to rebuild them myself and then sell them?

Bill
Click to expand...

I'm not sure where this came from, but I vote to go ahead and rebuild and sell. We need vendors that can do these jobs.
 
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