The Stovebolt Site Forums The Shop Area The Electrical Bay Ignition troubleshooting on '51 3100

I'm trying to start my 1951 3100, which hasn't been started in either 5 years or 20 years, depending on whom you talk to. The starter works fine. Problem is, I don't seem to be creating any spark. I know I have juice to the coil. I checked the continuity of the coil (for what that's worth), and it was OK. I put a volt meter on the coil wire leading to the distributor, and it has current. If I remove the distributor cap, the rotor is going around. But if I hold a spark plug wire NEAR the top of the plug while cranking, or if I remove the plug and look at the electrode while cranking, I see no spark in either place. So my question is, what do I do next? I don't know how to test the condenser or the points, or any other part of the distributor. Help? And Thanks!

ol_red,

Welcome to the Stovebolt. I think the very least I would do would be to gap the points, pull the plugs and gap and clean them. With the key ON, a meter on the points side of the coil (-) should alternate between approximately 6 volts and 0 volts as the engine is cranked over and the points open and close.

This quick test shows that they are at least actually doing what they are suppose to do, and that the condenser hasn't failed.

If moisture is a issue, spraying the cap and distributor innards with WD-40 will displace the water and help dry things out.

Nasty fuel and crud in the carburetor might be a concern too.

With the key ON, and using a screwdriver, opening and closing the points should fire the coil. Holding the COIL WIRE near a ground should show a ZAP of some sort.

If the condenser is shorted after years of sitting, the system won't work. This is something that should be replaced along with the points. More help is on the way...good luck.

Stuart

Don't use old fuel. You'll risk siezing your valves.

old red
I would get a new set of plugs, you're going to want them anyway. Then you might think about replacing the spark plugs wires. Look at the cap and rotor, if they look clean then keep them. If the look dirty or pitted replace them. Next, I would get a new condensor just to have. Then I would disconect the fuel line to your fuel pump. You then can hook up a gas can to the carb the will gravity feed the carb. Hook up some gas hose to the vent nipple of the gas can.

Check for spark at the new plugs.
no spark, replace condensor.
Check for spark at the plug
No spark pull cap and check for spark at points.
If you have spark at the plug.
Then reinstall plug and attempt to start motor
no start but spark check timing.
adjust timing as nessesary
reattempt to start.

It may take you a while but you will get it. Heck I did and if I can do it anyone can! Good luck
And welcome to the 'bolt!

Thank you all for your help. I didn't tell you that the parts (dist. cap, points, condensor, rotor, wires, plugs), are fairly new and very clean. They're 5 years old but have almost zero runtime on them. I ended up replacing the condensor and points--had no idea that would cost $22! I now have spark at my spark plugs, so that's great.

Two more questions, please:
1) I'm not getting power from the ignition wire when I turn the key, so I've run a jumper from a hot terminal to the coil, therefore, the coil is always hot. Can this cause damage, or is it otherwise a bad idea?
2) I know my firing order is 1-5-3-6-2-4, but I don't know if I have the #1 plug wire in the right hole on the distributor cap. The shop manual says to plug #1 into the hole farthest from the block, but it's hard to tell exactly which one is farthest, so I may be one hole off. Even if I have the relative order of the plug wires correct, I'm guessing it would be a problem if they were all one hole off, or two holes off, etc. Right?

ol_red,

It is indeed a bad idea to have the ignition powered all the time. This will lead to a cooked coil and maybe cooked points. Are you sure you have the key switch ON when you are looking for power at the coil? The key switch has a nontraditional position for ON.

You might be able to rotate the distributor enough to make up for being off one cap hole, but not two. If you want to be sure of where you are, pull plug #1 and bump the engine over until you feel a blast of air rush by a thumb held over the hole.

If you look above the starter, there is access hole in the bellhousing with a little pointer attached. This is where you time the engine. After you feel the air blast by your finger, you need to slowly pull the engine over in the direction of rotation, looking for a BB that is embedded in the flywheel.

This BB can then be aligned with the little pointer. This will indicate TDC on #1. Now you can pull the distributor cap, note the location of the rotor and stick #1 wire in the tower over the tip of the rotor.

If this is all to technical, you can fiddle until you get the engine to pop, then adjust the distributor manually. Moving #1 a spot in the cap can get results too..one method gives you instant results while the other can get the job done, just slower.

Stuart

Thanks very much, atomarc. Your suggestions make perfect sense. I can do that!

Regarding the key position, I recently realized its non-traditional position. Straight up is ON, but I assumed that was OFF. Nevertheless, even after allowing for this, I still have no power to the coil with the switch ON. The wires are original and the insulation and many connections are in bad shape. I'll fix this circuit rather than wiring the coil to a hot terminal. Thanks for the caution.

i would get new points anyway they may have a coating built up just from setting and there cheape