Ready to Run Distributors

[Rick]

Any one have experience on wiring up a MSD 8388 ready to run distributor. The instructions are vague on what to use as the 12 Volt power source.

For your 12 volt source do you use the ignition start line or the igniton run line.

On a 74 satellite they are the the bulk head location #22 ( wire # J3) and #23 (wire # J2)respectively. The igniton run line comes back into the original distributor thru the orignal electronic control unit.

Having an issue visualizing how this will work. If I use the ignition start wire as the 12 volt source will the #8388 continue to receive voltage once the ignition key is moved to the run position.

Vice versa if I use the ignition run wire will the #8388 receive voltage to start the engine up?

Or should I pigtail both the ignition run and start wires together and connect this to the MSD distributor as the 12 volt power source. I am thinking the last scenario.

 

[old_skool]

The ignition run maintains power when starting, DO NOT connect both by twisting, this will cause the starter to remain engaged and immediately activate in the run position, get a manual, wiring like this by the seat of your pants is what causes fires, not being harsh, but you'll be better in the long run. Use the original wire that went to the control unit that you are no longer using.

 

[Rick]

Thanks old skool. The manual is vaque and a call to MSD suggested hooking up both wires which didnt seem right. What you are saying makes sense but how does the field coil get activated to produce spark without wiring in the igniton start circit. Maybe over thinking this and yes definetly dont want a fire.

 

[old_skool]

Do you have the pdf instructions, I have a copy if you don't

 

[Rick]

Yes I have both. Please refer to my original question. The instructions are vague on what to use as the 12 volt powe source.

 

[Hemirunner]

There are two wires providing voltage to the coil, the ignition start wire (full 12v) and the ignition run wire (8-10v or whatever comes out of the ballast resistor) You can bypass or eliminate the ballast resistor with the msd coil and tie those two together to provide power to the RTR distributor in both the ign start and ign run key positions.

 

[bm02tj]

Make it look stock by removing ballast resistor and replace the resistor inside the ballast with a solid wire out of sight then you have full voltage to the MSD

 

[Dragon Slayer]

I am not familiar with the 74 wiring, but I did redo a 70 RR. The diagram shows you connecting to the coil +. So unless you are directed to remove other ignition system items, why worry about what is happening upstream? For a points 70 system, as already stated the ignition Start just jumps a ballast resistor to give full voltage at startup. The run is required to operate after startup. So I imagine both ign wires go into your original ECU and the wire coming out to the coil + is the wire you will use for your distributor +. G

 

[Hemirunner]

I am not familiar with the 74 wiring, but I did redo a 70 RR. The diagram shows you connecting to the coil +. So unless you are directed to remove other ignition system items, why worry about what is happening upstream? For a points 70 system, as already stated the ignition Start just jumps a ballast resistor to give full voltage at startup. The run is required to operate after startup. So I imagine both ign wires go into your original ECU and the wire coming out to the coil + is the wire you will use for your distributor +. G

The MSD systems need 12+ volts at all times. You need to eliminate the ballast resistor.

 

[Rick]

Thanks to all helping me to understand. I have eliminated the original ECU and ballast resistor and pig tailed both the ignition run and ignition start wiring onto the (t) side of the coil. Currently trying to eliminate the wiring for those pesky seat belt interlock circults. I picked this project up and it has along way to go. But getting the engine running is my first step. Will let you know how it starts and runs.

 

[maxwell]

Any pics of how this looks under the hood, I am looking into the ready to run for my 68. and wondering if it worht it.

 

[QQBlue1]

I'm resurrecting an old thread . . . I have a 8388 MSD "Ready to Run" distributor that replaced the original points distributor (68' small block 318). The MSD has a three plug connector running from the base of the distributor and plugs into the matching plug runs from the coil and the ground. I'm assuming the ground causes the spark that triggers the coil and sparks the distributor. Other than the ground, it all seems internal and nothing is wired to the ignition per the diagram above or the ballast resistor or voltage regulator. Additionally, it looks like the old blue distributor wire from the harness is/was being used to power the electric choke on the carb. I wired all this in 10 years ago with a friend and now I'm trying to understand it better in order to replace the old wiring with a new harness. I keep looking to see if I'm missing something but I come up empty. Thanks for any advice!

 

[Rishi]

Thanks for any advice!

Start a new thread.

 

[RemCharger]

I'm resurrecting an old thread . . . I have a 8388 MSD "Ready to Run" distributor that replaced the original points distributor (68' small block 318). The MSD has a three plug connector running from the base of the distributor and plugs into the matching plug runs from the coil and the ground. I'm assuming the ground causes the spark that triggers the coil and sparks the distributor. Other than the ground, it all seems internal and nothing is wired to the ignition per the diagram above or the ballast resistor or voltage regulator. Additionally, it looks like the old blue distributor wire from the harness is/was being used to power the electric choke on the carb. I wired all this in 10 years ago with a friend and now I'm trying to understand it better in order to replace the old wiring with a new harness. I keep looking to see if I'm missing something but I come up empty. Thanks for any advice!

Post #10 answers your question ,but to reiterate;
Connect the two connections at the ballast together. Your current + wire at the coil stays there, and the red from dist connects to it. Orange to negative. Black to ground. Start car.
How much amperage is bled off by your electric choke is unknown.
I haven't used a choke in decades.