Distributor Malfunctions - loose pickup plate?

[PaulC]

Also be careful of some aftermarket dizzy caps and rotors. Some may have less than stellar qc as far as clearances go. I had one of each where the rotor top actually scored the terminals in the cap. Think it was a combination of poor tolerances on both.

[geospider]

Well, actually, it just stopped. was thankfully close to home. Called Steiny as I was walking back home, for all things, get the old one that leaked. since it still worked, knew I could go easily get the car back home. swapped in on the street. Never could find the rest f the rotor.
AR was awesome; sent them pics and they sent me a new one.
As I said, the original just leaked, so new seals and bearings and I know i have a good spare.

Agree with Paul about the rotor caps. I have heard about that. Always inspect the cap pick ups for alignment.

geo

[maxm50]

Hey all,
I have some interesting updates on this issue:

I ordered a new distributor from a vendor. It was not a rebuilt OEM, but rather a new reproduction (I knew this). However, it was obviously inferior to the original in several ways - poor quality gear, no felt washer/plastic washer assembly, no o-rings on shaft, and a pretty bad quality cap and rotor. The vacuum advance also has a stiffer spring in it (thus will not give the same advance curve as stock).

I pulled my distributor out and used this new one (with my old cap and rotor) for a few weeks. All in all, it works OK but I'm not impressed. I'm worried about its longevity, poor vacuum advance curve, and I just don't like the fact that the parts are inferior to OEM. So I pulled it back out and disassembled both distributors to see if I could piece together one working distributor with mostly OEM higher-quality parts. I discovered that the only part that was bad on my original distributor was the vacuum advance PLATE. The plate that the magnet and pickup screw into. It's retained on the distributor shaft by what SHOULD be a very tight fitting bushing that the plate is swaged onto. However - this part on mine was obviously not original to the distributor (looked new and shiny, and a different plating on the metal), and the bore of the bushing was oversized by about 0.70mm. So it was not at all a tight fit on the distributor shaft. That's what was causing all the knocking around that I posted in the original video on this thread. So it's not a worn out part, it's an incorrect part that was put on there for some reason by the PO.

Then I tried swapping the NEW vacuum advance plate onto the OLD distributor, only to find that the new part is incompatible with the original style vacuum advance. The "ball" that the plastic end of the vacuum advance rod snaps onto is a much smaller size, and the screw hole pattern of the vacuum advance module is different. So, if you have one of these reproduction distributors, good luck ever replacing the vacuum module!

So - I'm on a mission to just fix my original distributor by replacing the vacuum advance plate. Does anyone have a spare good-condition OEM vacuum advance plate that they'd be willing to sell me? Must fit tightly to the distributor shaft and not rattle around. That one little part will let me get back on the road! Or if you have a rebuildable "core" distributor, I'd be happy to buy that and pull the part off myself.

I hope my experience will help to encourage others to do whatever you can to fix your original distributor rather than replacing with a reproduction. I wish I had just disassembled my original distributor and found out what the real problem was before ordering the reproduction, but I wanted to get back on the road quickly and hindsight is 20:20...

Pics here of the vacuum advance plate. This is the one with a proper-sized ball but oversized bushing ID (of course you can't tell that from a photo). The reproduction vacuum plate has a much smaller ball on it.

[18Fiatsandcounting]

Sorry to hear about all the troubles with the new distributor. On your old one, could you have a machine shop make and press in a new bushing (collar) that would fit snugly against the distributor shaft? Maybe spot weld the new bushing to the plate?

All my spare distributors are centrifugal advance only so I can't help you there, but you could try posting a Wanted ad in that section of this forum.

-Bryan