The Stovebolt Site Forums The Shop Area Engine Shop 1951 3100 No Spark at plugs.

I am flummoxed. Electrical is not my best suit. Really, all I know about electricity is the its useful, invisible and dangerous. The kids and I in my school shop are trying to get the old girl running for the new owner who is going to give us TIG welding instruction in trade. Last known operation was in 1982. I have spark at the points, 6 volts at the bat terminal of the coil. and 6 volts at the ign terminal of the coil, which changes as the points open and close. Same result with two different coils. No spark at the plugs. rotor looks new, as does the cap and wires. Any ideas???

Ron,

I just went through this too. Check your static timing. BB/ ball on the flywheel on the pointer with the no. 1 cylinder at top dead center on compression. If the timing is off, your spark will be very weak or not at all. Once you get her running you can time it with a timing light.
Have fun.

Mark

Ron,

This might be dumb, but you did check that the rotor is turning when you crank the engine. Right?

SimS

I forgot to mention that when you do the static timing and the ball is on the pointer with the no 1 cylinder on compression, the rotor should point at the no 1 cylinder on the distributor cap. If it's off, loosen the clamp and turn the dizzy until it does. THEN, when it starts, you can dynamically time with a light. Sorry about that. It's a little early here.

Check what SimS also said.

Mark

Ron,

One more thing. I know that you changed the coil, but is it giving you a nice fat blue spark, when you turn the engine over?
Pull the coil wire from the distrubutor cap and hold it near a good ground and turn it over. If that is ok then do the timing. Sorry this is not in the correct order. The coffee is just now beginning to work its majic.

Mark

Thanks, that gives me a good number of things to try at school on Monday. The distributor wobbles a bit also when you grab hold of it, and the clamp is tight. It may be very badly worn. Ron

rotor is turning, yes

First, find out if it WILL make spark and forget about timing, point gap, and everything else. Get the cap and rotor out of the way so you can use a screwdriver (plastic handle) to rattle the points open and closed with the ignition switch on and the coil wire in the coil and with the end that usually is in the cap about a quarter inch from a good ground. If it makes spark turn the switch off and set the points at .016-.017" with a feeler gauge. Now turn the switch on and spin with the starter---no spark, the points are bad. If it makes spark this means the rotor or cap are the problem. A bad coil or condensor are a possibility but nine out of ten times when one of these old engines has sat for a good while and has no spark the points are the culprit.

Amen, what he said, But prove the coil/distributor high voltage wire too.If it is open the coil output can not be distributed.

Hey Ron,

Any progress yet?

Mark

Hello Bolters!
I have a 53 GMC 3/4 ton 228. I have been driving here for the last 3-4 years with no worries. Drove her last about 3-4 months ago. Ran great with no issues. Went out yesterday to fire her up and nothing. I've replaced the plugs, coil, and wires. Cap looks good, cleaned up the points and rotor a bit with 220 grit. Nothing. Primed the carb with a little gas, nothing. Pulled the plug and looked for spark. Nothing. What am I missing? I need to get her running by Sunday for a wedding. It did fireonce right after I replaced all the plug wires, but that was the only sign of life.