Vacuum advance makes car shut off...WTF??

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Reddartowner

Reddartowner

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Here's my problem,

We have been running my son's '68 Dart without the vacuum advance connected (it was that way when we bought it). After installing a new intake and carb this week, we decided to hook up the vacuum advance in hopes of improving gas mileage somewhat. When I hooked up my vacuum pump to the advance can to get a reading on how much the can would advance the timing, the car shut off as soon as I started to apply vacuum to the can. The distributor is an electronic Mopar factory piece, with .008 between the reluctor and the pickup. While inspecting the dist I noticed that the pickup plate could rock on the slide points and cause the pickup and reluctor points to touch (removed from car). The mechanical advance works fine, and the car runs fine unless we connect the vacuum advance. Do I have a worn pivot pin on the pickup plate or is it something else..??

Thanks.....
 
Touching of reluctor and stator is not good. I would think the plate bounces from that, and timing is altered in an undesirable way.

I think wear or assembly are the issues.
 
I was thinking that the pivot pin on the pickup plate might be worn, or the pivot pin hole in the base plate, allowing the plate to rock. Guess I'll have to pull it apart and check that.
 
It might be worth checking the stops on the vacuum control. Perhaps they have been altered in a way, for too much travel.

There should be a clip to hold the plate down at the pivot point. Slop in the main shaft bushing, or wobble could be a problem too, exacerbated by the plate travel. There are also pads that support the plate. The grease can get sticky, resulting in bumpy travel.
 
Reddartowner said:
Here's my problem,

... While inspecting the dist I noticed that the pickup plate could rock on the slide points and cause the pickup and reluctor points to touch (removed from car). Thanks.....
Click to expand...

There lies your problem. The vacuum advance is pulling on the plate & causing them to hit. Mechanical advance doesn't pull on the plate it rotates it as a whole, so it won't cause it to **** & hit. I'd check for worn out plate &/or bushings etc.
 
OK, so I know where I need to focus my attention. It's either going to be the pin on the pickup plate being worn, or the hole in the baseplate when the pin goes is worn. Finding a new pickup plate assembly is easy, but does anyone know where I can find a new base plate (the part that screws into the distributor body..)..???
 
Reddartowner said:
does anyone know where I can find a new base plate (the part that screws into the distributor body..)..???
Click to expand...
I had this problem when I got a new e-distributor for my 64 slant off e-bay since it was missing the internals. As you found the pickup plate is easy, just $7 at rockauto. I had to swap the baseplate from my points distributor. Fortunately, they appear to be the same between points and electronic distributors.

What engine do you have? If SB or RB, a new "ready-to-run" distributor is only $50 and appears to have a much better pickup design, plus an HEI module.
 
BillGrissom said:
I had this problem when I got a new e-distributor for my 64 slant off e-bay since it was missing the internals. As you found the pickup plate is easy, just $7 at rockauto. I had to swap the baseplate from my points distributor. Fortunately, they appear to be the same between points and electronic distributors.

What engine do you have? If SB or RB, a new "ready-to-run" distributor is only $50 and appears to have a much better pickup design, plus an HEI module.
Click to expand...

You mean an HEI compatible pickup right?
 
TrailBeast said:
You mean an HEI compatible pickup right?
Click to expand...
I was just talking about fixing his Mopar electronic distributor. It can trigger either the factory Mopar module or a GM HEI module. I think he will need to find a junk distributor to get the baseplate.

My comment on the "ready to run" distributor is that it costs only ~$50 and gives you a brand-new distributor with a better designed pickup. You could wire it to trigger a Mopar module, though I would use the built-in HEI module, lose the ballast, and run a better coil.
 
I would have to assume everything about the distributer is worn out. If the shaft is loose in the housing bores also, replace the entire assembly.
 
I'm going to install a rebuilt dist that I ordered from Autozone and see where that gets me. As mentioned, that also eliminates the possibility of wear in the other components as well. And for the $40 price I could hardly replace the components in my old dist.
 
Reddartowner said:
I'm going to install a rebuilt dist that I ordered from Autozone and see where that gets me. As mentioned, that also eliminates the possibility of wear in the other components as well. And for the $40 price I could hardly replace the components in my old dist.
Click to expand...
Good idea!
Let us know how you make out.
 
Update.... Turns out the reluctor wires were reversed, so the distributor was out of phase. Switched the reluctor wires and re-timed the distributor and now the vacuum advance can be connected with no problem. Only now we have to find a vacuum advance can that adds less than the 28 degrees that this one adds....
 
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