Dual Point Problem

[HALIFAXHOPS]

Hey a big issue with most dual points except what was noted id check the ground between the distributor and the block. A metal gasket is needed, a fiber one will not conduct the ground, and just the ground through the clamp is iffy if the distributor is painted. Also double check the condenser easy check . If you have a noise suppressor condenser check that also usually on the coil.

Here is one way will not check the capacity though more of a pass fail. Use a analogue meter!

How To Check a Condenser on a Points Ignition

I get asked this all the time. I have a condenser tester but I do it daily. This will work for you. This is for an analog meter but a digital works--you will see the voltage spike. Hope this helps 1.) Remove the condenser from the engine (or...

www.forabodiesonly.com

 

[Stumper]

Hey a big issue with most dual points except what was noted id check the ground between the distributor and the block. A metal gasket is needed, a fiber one will not conduct the ground, and just the ground through the clamp is iffy if the distributor is painted. Also double check the condenser easy check . If you have a noise suppressor condenser check that also usually on the coil.

Here is one way will not check the capacity though more of a pass fail. Use a analogue meter!

http://[URL]https://www.forabodieso...o-check-a-condenser-on-a-points-ignition.186/

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Oh, boy…. I think you just hit the nail into my head… When I put the distributor back in I added an O ring to the bottom ‍. Thanks for this !!!

 

[HALIFAXHOPS]

It is ok if it has the grove for one not on top of the block. Grounds do weird things to point systems. I see it on the distributor tester. The spark kind of walks hunting for a ground hard to explain. I have a few metal gaskets left if you cant find one. Getting rare! I get alot of crap saying that usually internet believers.

 

[AR67GTX]

That metal gasket is a good tip that I forget. I have one on both of my Mopars. Although you would think the clamp and bolt would ground the distributor. But sounds like you can’t always count on it.

 

[ynst]

That fine strand wire is called Litz (Litzendraut) wire.

It's tough to find insulated Litz wire, though, and you really should use insulated, as opposed to bare, wire so that it doesn't short to the connecting strap between the two sets of points when the vacuum advance rotates the point base and creates a slight kink in the ground wire.

The cheapest insulated Litz wire I could find was ONLY available in spools and the minimum length was 100 feet. Kind of expensive when you only need two or three inches. I wish I still had the spool my father had when he used it for dial cord wiring when he repaired radios in the fifties.

 

[Carcinogen]

I had wiring problems that turned out to be corrosion under the insulation.

Was chasing an intermittent problem and had replaced parts and still had problem. Wiring was only thing left, insulation looked good but copper was discolored with areas of green. Inside near connector was worse but even in the middle with no damage to insulation was corroded.

 

[RJRENTON]

You can eliminate 50% of dual point dist problems.....by using a single point dist...

What a STUPID comment......the OEM Prestolite dual point is a reliable, easy to set, easy to recurve unit. I set mine, out of the car, where it's easy to access the screws to replace components and to set/adjust points.....0.001"-0.002" variation between each set and overall specs is TOTALLY acceptable and the world WILL NOT come to end if not exactly the same (despite of someone may believe and THINK they can tell). If using dwell settings, +/- 2 or 3 degree variation will be acceptable. The OVERALL initial advance will be set when reinstalling the distributor.....to what ever degree YOU or the engine likes......
BOB RENTON

 

[Rebelrouser]

Looking for feedback on my Latest challenge. A few months back I suddenly had an issue where my engine would cut in and out under any amount of throttle. Found the problem by pulling the vacuum line off the timing advance which resulted in the engine settling to normal - at first. After a few tries of putting the vacuum back on and off it finally would run at all. Found that the primary power wire inside was broke. After I pulled the distributor to replace the wire also found the bridge wire between the two contacts nearly broke. I replaced the wires along with new points, condenser put it back in and everything ran fine for several outings. I suspected that the problem was the wires were all old originals and that the action of the advance moving the dist back and forth resulted in the wires breaking.
Fast forward to Saturday. Started the same type of skipping of the engine to the point that I couldn’t really put any load on it. Even backed fired out the exhaust a couple of times. I pulled the cap and all the wires inside looked good and tight. Tried again but same problem. I pulled the vacuum line to the advance and it runs perfect…..

A “shop” that had my car some months back replaced the vacuum advance unit with a new one from Tony’s Parts. Since the car runs good without the advance connected I’m thinking the unit is bad. Haven’t had it apart yet but anyone have thoughts? When the distributor was out a few months ago it didn’t seem to have any play and was oiled up good.

Could be a lot of things, but if it is an old original distributor the bushings and or rubbing block could be worn out. Easiest way if you can find a good mechanic that has an ignition scope, you simply look at the raster pattern and the points open signal should stack on top of each other if not the distributor is worn. One way to limp it along is to set the ignition points tighter say .010. What happens is as the rpm goes up the shaft will center itself in the worn bushing and open the gap of the points. You could also leave the dwell meter hooked up and watch it when driving if the dwell changes a lot, may show the issue. Vacuum advance pulls on the plate, so watch the dwell when applying vacuum to the advance.

 

[WileE]

From your symptoms a Catholic Priest may be in order

 

[WileE]

What a STUPID comment......the OEM Prestolite dual point is a reliable, easy to set, easy to recurve unit. I set mine, out of the car, where it's easy to access the screws to replace components and to set/adjust points.....0.001"-0.002" variation between each set and overall specs is TOTALLY acceptable and the world WILL NOT come to end if not exactly the same (despite of someone may believe and THINK they can tell). If using dwell settings, +/- 2 or 3 degree variation will be acceptable. The OVERALL initial advance will be set when reinstalling the distributor.....to what ever degree YOU or the engine likes......
BOB RENTON

Bob... Bob... you forgot to say "just my opinion of course" . ( just my opinion, of course )

 

[Geoff 2]

And Bob has lot his WONDERFUL sense of humour while he was on vacation.......

 

[AR67GTX]

I rebuilt the 2 dual points I have in my car and they function great. Dead steady dwell. I have given up changing/setting points with the distributor in the car. My hands are vision just aren’t as good as 50 years ago. I pull the distributor and do it on the work bench.

What I noticed on an old single point I had on my 440, when the vacuum advance pulled in, it changed the dwell reading by 2 or 3 degrees. Another forum member pointed out what was happening which had to do with the advance arm pulling across on the points plate. Could have been due to some wear on the points plate center pivot but seems he said that’s just the way they are.

 

[RJRENTON]

I rebuilt the 2 dual points I have in my car and they function great. Dead steady dwell. I have given up changing/setting points with the distributor in the car. My hands are vision just aren’t as good as 50 years ago. I pull the distributor and do it on the work bench.

What I noticed on an old single point I had on my 440, when the vacuum advance pulled in, it changed the dwell reading by 2 or 3 degrees. Another forum member pointed out what was happening which had to do with the advance arm pulling across on the points plate. Could have been due to some wear on the points plate center pivot but seems he said that’s just the way they are.

In the Prestolite dual point distributor, the breaker point mounting plate pivots on a CONCENTRIC, ball bearing mounting plate, which will not be effected by the operation of the the vacuum advance mechanism. This is TOTALLY different from the single point distributor operation, which the breaker point plate pivots ECCENTRICLY, which is why the dwell changes with vacuum advance changes.
BOB RENTON

 

[Stumper]

Still fighting this battle. I’ve tried new condenser, coil and ballast resister. Here’s what I’m seeing. The engine turns over fine but I’m not getting spark to fire it off. I have 12v to the coil with the distributor primary disconnected. When it’s connected I drop to around 5v on the hot side and crazy voltage numbers on the neg side ( 20-30 all over the place).
In the distributor the ground wire is good — although the rivet to the plate is a bit loose. Primary wire in is good and not grounding on the case. Connecting wire between the points is good. What the heck am I missing?..

 

[gtxrt]

disconnect the condenser wire and try it.

 

[Geoff 2]

I said earlier in this thread half in jest, half in all seriousness that 50% of dual point dist problems can be eliminated by using a single point dist. One less set of points & condenser to fail, plus attachment/mounting points that can fail. Try a single point dist.

 

[Stumper]

Any chance it could be a main coil to distributor wire that measures OL when testing resistance …..?
Almost new set of wires that I got from Mopar Mall… Never would have thought to check a new wire ….

 

[HALIFAXHOPS]

Thats telling me it is open! Make sure the meter is on the right scale. Does not explain the short in the dist though.

 

[Stumper]

Well, it wasn’t the wire. Tried a known good secondary and it also measured OL on the bench.. Found that my meter has separate modes for continuity and resistance. Both wires are around 6.5ohm…

BUT, I did find this. The wire coil is still intact, although stretched and the center insulation is obviously broke. Still showing 0.7 ohms cold

 

[Stumper]

disconnect the condenser wire and try it.

Didn’t help