No spark slant points &condenser

[Shadow]

Stumped on this one. I think I’ve narrowed down the problem but don’t know how to fix it. Have 12 volts to coil on both sides even when points closed. Distributor seems to be grounded ok, so why is the voltage not dropping on negative lug when points close? I have 12 volts also on lug inside distributor where condenser hooks up so my lead wire there is good.
Bad distributor?
Have replaced points, condenser, and coil.

 

[Shadow]

Can also add this: that with ignition turned on and moving points closed and open by hand: no spark jumping across points

 

[Charrlie_S]

Are the points actually making contact? With points closed, and ign on, use a test light or volt meter, and see if you have voltage on the "moveable" point. If yes, see if you have voltage on the fixed point. If yes, the point set is not grounded. If no, the points themselves are not making contact.

 

[Vaanth]

Stumped on this one. I think I’ve narrowed down the problem but don’t know how to fix it. Have 12 volts to coil on both sides even when points closed. Distributor seems to be grounded ok, so why is the voltage not dropping on negative lug when points close? I have 12 volts also on lug inside distributor where condenser hooks up so my lead wire there is good.
Bad distributor?
Have replaced points, condenser, and coil.

It sounds as if the distributor wire between the negative (-) terminal on the coil and where it attaches to the point set is open. If the wire looks intact, it could be broken inside the insulation, at a terminal end, or withing the point set. Or the mounting of the point set to the breaker plate is not making contact.

Edit: strike the first sentence. Followed up in post #6.

 

[Charrlie_S]

It sounds as if the distributor wire between the negative (-) terminal on the coil and where it attaches to the point set is open. If the wire looks intact, it could be broken inside the insulation, at a terminal end, or withing the point set. Or the mounting of the point set to the breaker plate is not making contact.

OP says he has voltage inside the distributer at the terminal where the wire connects to the points.

 

[Vaanth]

OP says he has voltage inside the distributer at the terminal where the wire connects to the points.

Thanks, I missed that. Then it's more likely a grounding of the point set issue, or the contacts are not making contact to each other.

 

[Shadow]

Problem solved!!
Swapped distributor and she fired right up
Something in the distributor was bad, sure seems like a ground issue. The points were making contact as I was manipulating them open and closed wanting to see a spark jumping across but it wasn’t happening. Luckily I had a spare distributor!!

 

[halifaxhops]

Sounds like a shorted condenser.

 

[Charrlie_S]

Sounds like a shorted condenser.

With a shorted condenser, he would not have voltage at the connection on points/condenser wire, as the condenser would be the same as the points being closed.

 

[halifaxhops]

LOL your right need coffee!

 

[Charrlie_S]

LOL your right need coffee!

I already had two
I knew you knew better, figured you just misread something. Just didn't want some to be misled.

 

[halifaxhops]

Just weird he change the dist that had new points and cond and it worked. Re thinking this dirty points not making contact. Does happen.

 

[Charrlie_S]

Just weird he change the dist that had new points and cond and it worked. Re thinking this dirty points not making contact. Does happen.

I have had that happen with a vehicle sitting for an extended time with the points open.
Back "in the day" we used to screw with guys by taking a piece of scotch tape and putting it between the contacts. So thin and clear, it was hard to see.
Another thing we would do would be to swap the coil wire with a spark plug wire in the dist cap. Car would'nt start but would hit on one cyl. leading the drive to assume he did not have an ign problem.

 

[Shadow]

Actually the distributor that I had in it had brand new points and condenser. The one I swapped in to get it to run had old p&c

 

[Charrlie_S]

Actually the distributor that I had in it had brand new points and condenser. The one I swapped in to get it to run had old p&c

It sounds like the points are not being grounded to the dist housing. Check with an ohm meter. or test light to find where the problem lies. Just because "NEW" does not mean good. The end user/consumer is the final quality control inspector (unpayed).

 

[67Dart273]

Somehow I missed all this. This is a GREAT example of WHY GOOD TROUBLESHOOTING (and in this case add the word "simple") can save a lot of time and grief

LET'S GO OVER THIS.

For the naysayers, I KNOW that electron flow is neg to pos. But I tend to thing the other way in automotive. What do we have?

We can forget the key/ harness because the OP has said that he has 12V to the coil

So we have a coil, the distributor lead eyelet terminal on the coil Neg, the distributor primary lead, the eyelet on that wire to the points, the actual points, the connection to the advance plate, allegedly in contact with the distributor case, and allegedly the distributor grounded to the block

So here we sit. 12V on coil +, on coil-, I assume 12V at the points terminal. All you need to do is run through the circuit.

Probe coil +, 12V. Probe coil -, 12V. Probe the points terminal, I assume 12V. Probe the points mounting frame, do we have 12? Probe the advance plate, do we have 12? Probe the CASE, do we have 12?????

The point (ha ha, pun intended) is that with about 1 minute at the outside and any cheap meter or in this case even a test light, you can run this down

HOW DID YOU KNOW the points were conducting. You said "they were closed." That does not mean they were making contact. So if you had 12v at the points wire terminal BUT NOT 12V at the points mounting frame, then you would have KNOWN that the points are actually oxidized or maybe not for certain closed. Or if you had 12V on the advance plate but not on the dist. case, then you would have known that somehow, even tho improbable, the advance plate was NOT grounding to the case.

Factory dual point distributors had ball bearing advance plates, and had to have a separate grounding wire to get a good connection between the plate and the distributor case. That does not mean that single points dist's can't have the same problem.

 

[BillGrissom]

When faced with such, often good to test the distributor in the air, spinning the shaft by hand. A points distributor needs its case grounded to the engine block (or BAT-) with a jumper wire. Leave the distributor cap off and don't disconnect the spark wires. Connect a spark tester (or spark plug with threads grounded) to the coil output post for the test. With IGN power ON, you should see sparks as you spin the shaft by hand.

Note that setting points gap is just to get in-ballpark. The gap should ideally be set to get the correct "dwell" reading on a dwell meter, as the distributor shaft turns. You might be able to spin it fast enough and steady enough by hand to read dwell. Never tried, but that would be good for a slant since adjusting the points with it in-engine is tough on a slant.

To skip all that fuss, a GM 8-terminal HEI module gives a stronger spark and controls dwell electronically. It requires a later e-distributor (many posts). I put that on all 3 of my 1960's Mopars (slant, 273, 383).

 

[RustyRatRod]

Just because "NEW" does not mean good.

Preach it, brother.