64vert

I just finished a valve job on my 65 L79 with stock points ignition and reassembled everything and attempted to start but I have no spark. When the heads were off I installed a new Lectric Limited ignition harness, everything seemed to connect properly, it cranks over just fine, but I have no spark. I did check a couple voltages, I have 12V at the + coil terminal with the key in the run position. I also have 12V at both sides of the ballast resistor with the key in the same position. The ballast resistor was changed last year. What would be the next step to troubleshoot this problem?

leif.anderson93

Did you check the gap on the points?? They might not be opening. You state that you have no spark but you didn't say where i.e. at the coil, at the plugs, etc.

64vert

Point gap is good, I am getting no spark at the plugs.

Boyan

Test the black ground wire on dist breaker plate for continuity....or just jump it and try to start. It may look fine, but breaks inside.
Boyan

Nowhere Man

Sounds dumb but do you have the plug wires on correct?

MikeM

Why not do a little trouble shooting? There's plenty of advice here if you use the search function?

64vert

I checked that wire for continuity and it is good. I also hooked a light up to the negative terminal of the coil and it flashes on and off while cranking. The plug wires are all on correct.

67vetteal

Pull the Coil Wire out of your Dist. Cap and hold it near a ground while someone cranks the engine over. Spark should be a crisp Blue color. You can also watch Points while turning engine over and see if there is a spark visible. Last resort run a wire from the Battery + to the + on your coil and see if that helps. Might just be a Coil gone bad. Al W.

66jack

Just a guess on my part but, Check the condensor...the one that hooks to points..

Powershift

Pull the short coil wire out of the cap. Have a friend hold it a 1/4 inch or so away from the block/manifold when you are cranking the engine. Make sure friend uses a rag or insulated pliers You should be getting a spark there.

Perhaps the center metal "tang" on the distributor rotor is not touching the electrode in the distributor cap. You can bend it up slightly.

If you had a dwell meter, you should hook it up and check for 28-30 degrees of dwell while cranking. This will ensure you have the proper gap and that the points are functioning okay.

What is the voltage at the coil + terminal during cranking?? When you are cranking the car with the starter, the coil gets its 12v power from a different wire than when the ignition switch is in in the "run" position. Maybe that second power source wire is bad. It comes from the starter solenoid small, side "R" terminal. The coil + terminal should have two wires attached to it: one from the ballast resistor and one from the starter solenoid.

Larry

garrbw

Try reversing leads under the cap. I can't remember if the condenser wire is on the outside or not. This will keep it from firing

MikeM

I believe you have narrowed your problem to either the coil or condenser with the check you did here. That is, unless you forgot to install the rotor?

You did mean the test light while cranking was off/on/off/on, not bright/dim/bright/dim?

You shouldn't have 12 volts on the coil side of the resistor but that won't keep you from having a spark.

Powershift

Mike:

The 12 volts he stated was with the key in the "run" position………the points were likely open when these reading(s) was taken, resulting in no current flow and 12 volts on both sides of the ballast resistor.

Agree that when the car is running, the ballast resistor will have 12 volts on one side and 8 volts (or so) on the other side. But it ain't running yet.

Larry

64vert

It was a bad coil, I picked a new coil up at Napa on the way home from work and I now have spark. I can't start it in the attached garage so now I have to wait until I get home while it's still light outside to try again.

Thanks for the help.

SI67

Just curious to know what the coil that failed was. Original Delco, replacement Delco, aftermarket stock-type replacement, or aftermarket high-performance type?

Steve

64vert

It is an aftermarket stock type, I don't remember where I got it at, there isn't even a manufacturers name on it. It isn't more than 3 years old at the most. This time I got the Napa Echlin IC12, hopefully it will hold up better. I did get a chance to start it this afternoon, runs good, just need some final tuning.

Brian

67vetteal

Just had to be. Al W.