Hey guys. Trying to get an old touring car going. The car is a 1928 Graham body on a 1961 F100 ch***is, with the donor truck's complete drivetrain, including the Y-block. The guy inherited it & knows nothing about it, not even how to start it, and is not mechanically inclined. I checked the motor over and everything seems OK, so I pre-oiled the rockers and hooked a battery up to it. It took a while to identify all the unlabeled switches on the dash and find the hidden kill switches, once we finally got power to it we rolled it over for a while to let it build oil pressure then hit the ignition switch and tried to get it to fire. Nothing happened. Further diagnosis reveals... no spark! Ignition wiring confuses me, guys, so any diagnostic tips would really help me out. I pulled the distributor cap off to check for spark at the points and nothing. With my test light I can see that, with the ignition on, I have power to the ignition coil, and power at the points breaker arm, but as I said, I don't really understand ignition systems. I feel like with power at the points and power at the coil it should be sparking and yet I have nothing. What do I test next? What are the likely culprits so I can make sure I bring replacements next time I run out there?
See if the points are grounding before they are supposed to. And clean the points if they are corroded. Also, check the points gap and make sure its actually closing.
One likely problem is oxidation on the points...carefully rub some sand paper between them, to shine up both point surfaces. If they are badly pitted or oxidized, they might need to be filed. You can test whether they're working, by connecting a test light to the wire that goes from the points to the coil. It should show power only when the points are open, not when they're closed. If the light never goes out, then the points are not making contact (or there is a broken wire, or some other issue that you should be able to find using the test light and some patient thinking)
I forgot to mention the dist looks brand new and is Motorcraft branded. Doesn't necessarily mean the condenser or points themselves are any good but everything looks new in there. I'm thinking the coil may be bad but trying to imagine how power flows around this system gives me a headache - so not sure if that's a possible culprit with the symptoms I'm having.
Are the points opening and closing? This is a six cylinder chevy distributor but note that the red arrow is ponting to the rubbing block on the point arm where it is in contact with the tip of the lobe in the distributor cam. It has to be exactly on one of those tips when you adjust the points. The blue arrow points to the end of the arm and the point gap. I've checked more than one no start rig where they had gapped the points with the rubbing block on the flat of the cam rather than one of the tips. That causes the points to open wider but never close to build up the magnetic field in the coil. Another thing to check is to make sure that one of the leads to the ponts isn't installed wrong and grounding out. I've seen that happen and had it happen on my car when I was 16 and doing my first tune up on my 51 Merc. Got razzed by my shop teacher over that one.
So with the points closed, the test light should not illuminate when I touch the probe to the breaker arm? If I hold the test light probe on the breaker arm while rolling the engine over with the starter it stays on constantly. It is difficult to get an angle to see if the points are actually closing fully but I will make sure I check that. I can see the breaker arm move and maybe stupidly ***umed it was doing its job, it didn't occur to me the points might never be closing.
You want a good running car first. Then you figure out pertronix. Plus, with how he described the wiring in it, i wouldnt even wanna start messing with solid state.
One thing from another thread that popped up. If the ignition has a ballast resistor, is there a byp*** wire from the I post of the solenoid to the coil? If it has a key start switch some factory key start switches don't provide power to the coil when you are cranking. If it has a push ****on that isn't a factor but it may not be getting full voltage. I'd do what Squirrel suggested, Clean the points with some sandpaper or an emory board and set the gap at .016 and see if it will start then.
It does have a resistor byp*** wire and is a foot starter. I spent some time talking with others & drew a diagram of how I thought the ignition circuit worked. I drew it correctly as far as the components and wires go, but I was not really understanding what a coil is and how it functions; i.e. that the breaker arm is hot because the 'ground' side of the coil is hot while the points are open, because it connects to the positive side through the coil itself. The points closing and shorting the ground side of the coil to ground is what makes the coil work. I guess I had no idea what was going on before but now I get it. I'm going to start with cleaning the points, then make sure they are closing all the way. If so my next step will be to replace the ignition coil because I have one handy anyway. I don't think there's anything else in this circuit that could cause no-spark other than the condenser but it should be brand new. I should also make sure that nothing is jacked up & grounding to the distributor body. I remember chasing my tail for ages over a forgotten isolating washer in my Model A distributor...
Got it going!! I determined the coil was dead so I replaced it. Had spark after that but it was weak, cleaned & set the points and it lit right off with gas down the carb. Getting gas from the tank will be stage 2...
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