49 Chevy ignition troubles

[xtreme80]

Hey guys, I come to you with a question that's just puzzling me.

A friend of mine just got a 49 with a factory 235 straight six in it. It's also been converted to a 12 volt system.

My issue is that I can't get the ignition system working. I ran a wire straight from the hot on the battery, through a resistor and to the contact on the coil. The second wire comes out from the other contact on the coil, and runs to the point on the distributor. I've used a test light and traced that circuit all the way from the battery down to the point on the distributor, and I've got power all the way.

I've verified that the motor is spinning the rotor in the distributor, but for some reason I can't seem to get power from the primary wire to the spark plugs to create a spark. The primary wire is good, the plugs and plug wires are good, and it's got a brand new coil in it. I also ran a ground strap directly from the distributor to a good chassis ground, and nothing.

Any ideas guys? Thanks for any help!

[OrrieG]

You did not mention a condenser inside the distributor attached to the points. Does it have one? Is it good?

[xtreme80]

Forgive my ignorance, but the condenser is the round unit with a single wire that's attached to the point right? If so, then I'm only assuming it's good because it looks brand new
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[tmoble]

check that power wire from the batt is connected to the coil terminal marked with a +. from the post marked with a - the wire goes to the distributor, inside through a grommet and to the moving arm part of the points. The condensor (technically a capacitor) is also hooked to the same spot. when the points are open the coil charges. when the points close it grounds the circuit and charged field in the coil collapses. this is what actually causes the spark. The points must open and close while the engine is turning. if the adjustment is too tight they never close, too loose and they never open. Either way, no sparks.

You can emulate the circuit by hooking a power wire to the + side of the coil, use a jumper wire connected to the neg - terminal, tap it on ground. have the coil wire in the coil tower and held near a ground. you should get a strong blue snapping spark when you ground the jumper wire. just tap it, don't hold it on ground. There can be high voltage present momentarily in the jumper wire as the field collapses, don't hold it with your bare hand. Don't ask how I know this.

If all this works, the points are adjusted and still no sparks check for the presence of a ground wire running to from the points plate to the distributor body. If it's not there you might not get a good enough ground through the points to trigger the coil.

[solidaxel]

I am sure you have the points set for .020 and are VERY clean!

They are opening and closing (.020) whith the rotation of the engine, right!

The wire that is attached to the points and condenser make sure it is NOT touching any metal in side the distributor (grounded).

Do you have 12VDC at the wire that is attached to the points before you connect it to the points.

Check after you connect the wire also.
Try a new or different condenser

Keep us posted.

[mr48chev]

Tmobil and Solidaxel pretty well covered all the bases.

Problems usually happen when:

Someone sets the points on the flat of the cam rather than the tip of one of the lobes.

The connection on the points is grounded to the body of the distributor because it is in the wrong spot. or the insulator is missing or broken.


Sorry about the dirt. This distributor was in the front seat of a truck that sat up on the Horse Heaven Hills for 15 years.

[tmoble]

nice. looks like a real world distributor to me. It's just been stored near the south end of the north bound horses is all.

What grounds the points plate to body on that style?