2.4 MFI to a 3.0 CIS conversion? Wires?

[bobswei]

I posted this on the racing forum but thought I'd try here too:

I built a racer some years back and now am going from a 2.4S motor to a '78 3.0 SC motor. So, the new engine has a few extra bits to power. And, I'm not sure where to get the power from or, the sequence of valves to connect. I have a power wire coming straight from the battery and power coming off the alternator. I think, the termovalve and air valve act together? The WUR is straight forward? 12 volts in? Excuse the primitive drawing but this is what I have. Any knowledge in this area?
Thanks, Bob

[Trackrash]

I'm guessing that you don't have the SC's CIS harness? And you are creating a completely new harness? Oh my. Do you have an SC wiring diagram?

According to what I can tell from just deconstructing an SC harness the cold start valve is connected to the starter solenoid. The thermo valve and air flow valve are connected to the fuel pump relay.

The MSD needs a new heavy wire to the battery and one to the ignition switch.

Still using the SC's distributor?

[timmy2]

Bob, email me and include a phone number.
With a few questions on what you have for existing wiring, I can give you a full description of what you need to do.

[strictly]

theres an offer from timmy2 take it, otherwise you need a harness, or have timmy build you one!

With the harness, the main modification to the car will be easy, you just need both wiring digarams. I would not be working on the electrics without either!

[bobswei]

Yes, I still have the SC harness on the engine but I'm separating all the wires from what I need and don't need. Also using the stock SC dizzy. MSD coil. I also have the wiring diagram for the SC. The harness in the car, I made and is very simple. Power to ignition and oil temp, level, pres., alt and tach. No cold start anything or relays. Fuel pump in front is always on with return line to tank.
Makes sense that the cold start valve, I can connect to the yellow starter wire. Correct? Heavy red wire, from the alt, to the MSD, correct? So, if the thermovalve and air flow valve need a relay, then I......??? Do these two take continues power?
This is my fuse block in the front. Simple and effective for over 20 years.

[Trackrash]

You are keeping the CIS? That is what I understood in post 1. Then the only thing you will eliminate from the harness is the loop for the heater blower.

Are you using the six pin CDI? Or MSD ignition? You said MSD coil? There are a number of posts on setting up MSD ignitions.

Are you using the 14 pin connector in the engine compartment?

The SC harness has two differences from the older cars. The ignition wiring is incorporated into the engine harness. Unlike the older cars that had a separate harness for the coil and CDI. Also the hook up for the regulator does not go through the 14 pin connector as it did on the older cars as it has its own connector.

Others will have to chime in on how they hooked up the cold start and thermovalve, since the SC's fuel pump and starter wiring are different. In my case I am using carburetors.

Here is me figuring out my wiring.

[bobswei]

Trackrash, love the photo. I think, mine may be a bit simpler. I pretty much eliminated the original harnesses in their original form. I kept the 14 pin connectors and got rid of all the wires not needed. I know have 7 wires in each connector. I am using the MSD which has the instructions and seems fairly straight forward. Now that I know were the power comes from.
I talked to Dennis (Timmy2) and was a great help in simplifying what I have. Since yesterday, I got all the wires going to the 14 pin connectors installed. I'm now, working on hooking up the MSD and is going smoothly. I did have one question on this. Instructions say to connect large black wire to battery negative (opposite end of the car). Why can't I connect it to the chassis in the engine compartment?
Thanks for all the input. I'm no longer staring at it but working on it.