Has anyone had any experience with the MSD y block dizzys? I'm getting weak and sporadic fire at the plugs. My car sounds like it's only hitting on four cylinders. It's puzzling as last weekend we had it running and it sounded good but had to have a battery charger hooked up. As soon as it was removed it would start misfiring again. I thought I had a flooding problem because it smelled very rich but I now think it just wasn't burning all the fuel. When I put everything together I put all the wires to coil exactly back the way it was with the 6 cyl. Should I have ran a new wire to coil to produce a full 12 volts? If so where on the car can this wire run from?

Durham Missouri

The MSD three wire distributors (Ready to Run series) requires a full 12 volts to the red wire.  Hooking that up to a resisted voltage source will damage the electronics after a given amount of time.  Make sure the engine is well grounded to the frame if using an engine ground for the distributor.

Lorena, Texas (South of Waco)

Here’s the MSD wiring diagram for the 8383 Y-Block distributor.
 

Lorena, Texas (South of Waco)

If you still have the original ballast resister on the wiring going to the coil it needs to be removed..

Thanks Ted. I checked all the grounds. I have a ground from the firewall to the engine,engine to the frame,and battery ground to the block. The dizzy ground is on the block behind the intake. I think I'll try to find a keyed 12 volt source on the car and run it to the coil like the diagram. Is there a source on a 56 car that will supply 12 full volts at all times? I assume there is one on the fuse box? I'm no electrical guru by any stretch so I'll need a little help on this.

Durham Missouri

Your standard ignition wire should be fine on a 56 as the resister was not part of the wiring back then but a separate unit. To test, disconnect wires to distributor and ground your coil on the negative side. With the positive still connected to you ignition put a voltmeter on the positive of your coil and to a good ground. Turn on your ignition and you should get 12 volts. If you disconnect the ground wire on the coil then the voltage should rise slightly, maybe 1/2 volt, that is showing you the volt drop in you wiring and ignition switch (there will always be some). You need to have the coil grounded like I mentioned to give a load to get true voltage reading.

Thanks for the help. My plan is to remove the ballast resistory and run a new wire from the "i" terminal on the solenoid to the "+" side of the coil. Is this a constant 12 volt source? I couldn't really find to much info about the subject.

Durham Missouri

If memory serves me correctly, the 12 volts off of the “I” terminal at the solenoid is only active in the key start position.  You’ll need the 12 volt source that comes off of the ignition switch that originally went to the resistor that was mounted on the intake.  Someone else feel free to correct me on this if I’m wrong.

Lorena, Texas (South of Waco)

Ted is correct, the "I" terminal provides 12v to the coil when the key is in the start position. When the key is returned to the run position the power goes from the ignition switch to the coil. A ballast resistor is in line on that wire. You can remove that resistor and connect the two wires that are attached to it together to eliminate it, easier then running a new wire.

Thanks guys. Someone recommended the I terminal. While I have your attention I'd like to bend you ear one more time. Where is a good spot to hook up an electric choke?

Durham Missouri