‘67.5 R16 Not Firing - Ignition Electrics?

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SP3
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‘67.5 R16 Not Firing - Ignition Electrics?

Post by SP3 »

Reaching out separately from thread that was getting too broad on inop issues.

I followed the 2 schematics provided by Curtis to the letter. Thanks. Since I had recently acquired the car it was running just rough intermittently. I decided to replace all the ignition system components as a tune-up as I don’t know when they were done last nor did seller AND eliminate those items as contributory to the misfire condition. So prior to cleaning grounds and replacing points, condenser and coil, the car was starting. Took pictures of connections prior to taking stuff apart. After reassembly car just spins over but won’t come close to starting. Since initial replacement of those parts I also put new NGK plug wires on and installed another new coil for a points ignition system-still no starting. Ordered new rotor button but wrong one sent (would not fit distributor shaft) so scuffed end of old one that points to cylinders and re-used. There was a question on whether other new coil with 40k volts output was appropriate for ignition sys with points.

My multimeter was acting funny reading voltage, so I used my Test light. You clip it on a ground and the body lights up when the pointed end touches something that is 12 volts positive OR you can reverse connections to test for Ground conditions. It is pointed to pierce wire insulation to test for voltage at a junction in a harness etc.

So I tested the wires per schematic coming out of firewall to ballast resistor, coil and distributor when the key was turned to Start on the ignition switch and those wires tested hot. Hot across ballast, coil and wire that connects to side of distributor where condenser wire connects on outside and points wire connects on other side (inside the distributor cap). I was able to measure 7.2 volts on side of ballast that connects to positive side of coil. Also observed, with ignition switch turned to Start, the test light lit up bright on side of ballast with connection of Black/white wire. When I touched the other side (connecting to Positive side of coil) that post was lit significantly dimmer, which supported ballast working, stepping voltage down to 8 volts (7.2).

The thing that is concerning or maybe working as designed- The whole distributor test negative when I reverse the connections on Test light to measure for Grounds. The points plate, points, connection where condenser/points pigtail and Black wire from firewall terminates. Also never saw points arc when rotated to open (on lobe). When tested with Test light for hot condition at the points neither side lit the light. Also placing #1 spark plug on valve cover and spinning motor over, there is no arc across gap.

Should the distributor be grounded out and is that preventing no voltage to points or spark plugs?

In cleaning all the surfaces for better ground, removing paint on firewall where coil mounting bracket secures. have I introduced a Ground condition that is shorting out the distributor?

There appear to be 4 connections that were removed in replacing ignition parts that for some reason are not supporting firing now. Black and Black/white wires out of firewall to Ballast and Negative terminal on coil. Wire from out of Ballast to Positive side of coil. Black wire from firewall to distributor where condenser wire, points pigtail terminates.

Related: Fuse box connections cleaned, fuses replaced, correct Amperage confirmed and location in order. Battery voltage at 12.4 with everything off. Headlights, fog lights and running lights come on. Cleaned and re-gapped spark plugs at 0.029 in. Points gap set at 0.020 in.
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Re: ‘67.5 R16 Not Firing - Ignition Electrics?

Post by notoptoy »

There is a small ground wire that goes from the point breaker plate to the distributor housing, is this in place, and is it in very good condition?

It is very small, about 1-2" and a braided ground wire. with a terminal on each end.
Critical for the points application. If all else is in place and good, I would replace the condenser again.
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Re: ‘67.5 R16 Not Firing - Ignition Electrics?

Post by Linda »

Is the starter turning over well?
I think 12.4 on the battery is a little low, should be 12.6 or so as I recall. Can you charge battery to see if it helps?
Be sure there is enough fluid in battery.
Might want to clean the ignition switch also and the wires that go to it.
Check starter harness connections again at both ends.
The little pigtail wire in the distributor is kind of fragile so nice to replace it.
Edit: see you got new wires.
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Re: ‘67.5 R16 Not Firing - Ignition Electrics?

Post by theunz »

Have you checked for spark to the distributor cap from the coil and from the cap to your spark plugs? To do so remove the coil wire from the top of the cap and place or hold (if you hold use something insulated else your hair may stand on end) near an engine part and crank the starter while looking for spark. To check from cap to plugs, remove spark plug (or use a known good extra one) and ground the hex portion of the plug to engine and observe spark across gap. These measures will help narrow down your problem by process of elimination.
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Re: ‘67.5 R16 Not Firing - Ignition Electrics?

Post by SP3 »

Thanks for replies.

- Took off points breaker plate wire mentioned, inspected and cleaned both end’s connectors, so fresh metal and tight connection

- Starter spins over fine and fast. Is .2 of a volt that critical ~ 12.4 to 12.6? may have been my digital multimeter still moving to final reading

- Ignition switch operation turns on applicable fuses and wire from firewall that sends 12volts to distributor and worked fine before - so inclined to think is not issue.

- Connections at starter/solenoid are clean and tight

- Did test to confirm if distributor is firing to grounded plug on engine. Will try testing coil wire to ground for arc

My question is, is there something now grounding the distributor preventing points from being energized? New points install correctly and assumption is they are good. May order another set on the off chance they are bad out of box. Same with condenser.

I was thinking I had a wire crossed because car started before switching out components but swore I followed my pictures pre-switch out and wiring diagram.
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Re: ‘67.5 R16 Not Firing - Ignition Electrics?

Post by notoptoy »

The distributor is grounded through the engine block. This is why it is important that the plastic terminal block that goes through the side of the distributor is in good shape and properly isolates the incoming lead from the rest of the distributor.Make sure that either end of the white wire that goes from the terminal block to the points is securely connected and not touching any metal other than the terminal bolt and the point screw for attaching the wire. Post a picture of your set up so we can see if there is anything obvious that we might be missing. I would lean heavily toward a defective condenser if everything else is as you say.
Oh yes, one more thought, make sure the "carbon Pill" is in the center of the inside of the distributor cap. It is spring loaded, and should push up and down freely. If this is missing everything else will work, but you will get no spark at the plugs.
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Re: ‘67.5 R16 Not Firing - Ignition Electrics?

Post by Linda »

I am wondering if the higher voltage coil you got fried anything. I know you have the correct coil now. Coil wire spark should give the power you need to start as Mike said. That pigtail wire in distributor has a few fine copper wires inside and it is not too hard for them to break, so I would test it or just get a new one. I had a broken one long ago, so it was a problem
Maybe you can take a pic of the coil, ballast and distributor for more info.
Not sure if you got a new ballast but if not check that the backside is not rusted out.
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Re: ‘67.5 R16 Not Firing - Ignition Electrics?

Post by SP3 »

Will provide pictures of set up shortly.

Replaced Ballast resistor.

Will try coil wire test before reporting back. How does one test the braided breaker plate wire? As mentioned the ends are tidy now. Do you test for a resistance through it with a meter?
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Re: ‘67.5 R16 Not Firing - Ignition Electrics?

Post by mraitch »

you test the wire for continuity

have you confirmed that there is no ballast resistor INSIDE the coil??
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Re: ‘67.5 R16 Not Firing - Ignition Electrics?

Post by Linda »

Yes you can test for resistance.
Here is a budget multimeter from Harbor Freight that has an audible function for testing:
https://www.harborfreight.com/11-functi ... 61593.html

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Re: ‘67.5 R16 Not Firing - Ignition Electrics?

Post by jrusso07 »

Disconnect the condenser and give it a quick try. If it starts or fires, don't let it run as the points will arc and get damaged. Then replace the condenser. I have seen them shorted or open, right out of the box...more than once. Also, check the little conductive spring loaded button on the coil lead inside of the distributor cap. It contacts the rotor. I have seen these fall out leaving just an arc or spring contact to the rotor
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Re: ‘67.5 R16 Not Firing - Ignition Electrics?

Post by SP3 »

- Tested trying to start with Condenser disconnected and no luck.

- Placed coil wire spark plug end on valve cover and spun over engine and no arc to ground.

- Tested continuity of braided short wire to points breaker plate and do have continuity

- Interesting observation with old and current coil wire. Why do they not test showing continuity and the wires for spark plugs do?

Here are pictures of the environment:
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Re: ‘67.5 R16 Not Firing - Ignition Electrics?

Post by Linda »

Pics look OK except coil wire at coil may not be seated down far enough to make good contact. Try pulling back boot to stuff the wire in there well. Fuse box could be cleaner, I would clean up the wires and use new heat shrink.
Ballast resistor is correct one? Per the Tech Wiki schematic for 66-67 by Jim Bain, it says 1.6 ohm for the ballast resistor.
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Re: ‘67.5 R16 Not Firing - Ignition Electrics?

Post by SP3 »

Installed new points, condenser and rotor, set gap and engine fired for about 10 seconds but sounded like a cylinder was off - not running smooth and then will not start again.

Confirmed spark via grounding plug on motor and have arc across electrode.

The timing was never tampered with when prior running. Does the timing look way off?

Assuming since have spark at plug that condenser is still functioning and not fried since car started and then died? Engine dying was not from lack of 12 volts. Still have power, spins over fine, just no starting since.
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Re: ‘67.5 R16 Not Firing - Ignition Electrics?

Post by Linda »

I always put that pointer in the middle or 0. Then disconnect vacuum advance and plug it , put idle at 600 and time it 16 deg BTDC. Does rotor point to #1 plug when engine is at TDC? And I would have pointer on 0 when checking that.
And for instructional reference, you know how to find TDC?
Also for those who don’t know, you undo the bolt under the distributor towards the back, and careful not to overtighten when you are finished timing.
After timing if you want the idle higher than 600, do it then I usually have it at 750

Good that you have spark!

Linda
Sadly-Linda has passed away 2022. She was the 311's den mother and drove the first Rare-Parts ball joint project. RIP.
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