Help! Wiring problem

[71hcc]

I opened a real can of worms yesterday! I have a 62 fuelie with a 377 CI motor with the original Rochester FI on it. It ran great, but am tired of dealing with the spider perc with a hot start. It makes you not want to stop anywhere unless you are going to be there an hour or more. I'm putting a carb on to make it more user friendly. But thats not my problem, during the change over I found that I could run a HEI and clear my air cleaner. So here is where the can of worms gets opened, while doing the rewiring for the HEI I ran into someone elses mess under the dash on the ignition switch. I started to try to straighten out this mess, they had compleaty bypassed the amp gauge and went straight to the ignition switch and on to the fuse box. I was going to run the main power wire to the amp gauge and then come off the gauge to the ignition switch, fuse box and so on like the wiring diagram shows. Am I right so far? But what has me scratching my head is back out in the eng compartment. The charging system had been changed to a single wire alternator. It looks like there was a three wire alternator first because there are two wires folded back and taped. Now this is what throws me, the Alt. wires run back to a ford type of solenoid that is mounted on the fenderwell in front of the battery box. The alt. wire comes off of the other side of the solenoid and goes to the Batt cable on the starter. I don't understand what the solenoid is for? Any help would be greatly appreciated, thanks Jim

 

[62Guy]

I think the Amp was bypassed since it will not work correctly with your alternater. Look at this link:

Catalog

Does this resemble what you are seeing? Mad has a bunch of articles and parts to upgrade your older wiring system. I am incorporating some of these ideas in my rewiring of my 62.

 

[Rex S]

Many old style amp gages have been bypassed as they are a major fire hazzard. I would not recomend wiring it back into the harness. The old style amp gage required ALL the car's power to run through the gage (except starting power) and after time and use the resistance goes up due to loose, worn and aged components. Changing to a charging system with an out put of more than 35 amps (stock rating with maybe 45 being optional) is the final blow and the heat starts building which just adds to the problem. There are companies that will convert the OEM amp gage to a volt meter which vastly reduces the load. While behind the dash inspect the main lead very carefully for signs of overheating such as burnt or discolored insulation, brittle insulation, wire just doesn't "feel" flexable, etc. New harnesses are available for not to much money and they use modern wire. In the 64 factory book it states that wiring harnesses should be replaced every five years.

 

[71hcc]

Thanks guys for the input, I've done a lot of research the last two days and have come to the same conclusion as you. I know that old amp gauges can cause meltdowns and after reading up on one wire alternators I don't think that I will put it back on. I am going to rewire and put a three wire Alt. back on with a main power junction block like in MADs diagram. It does look like there was a heat issue it one time in the main dash harness. I am going to bypass the amp gauge and plan on buying a new harness in the near future. I am going to make my own Eng. harness as it doesn't make much sense to me to buy one when they aren't setup for an HEI. I still don't understand why that solenoid is there. Thanks again!

 

[JohnZ]

I still don't understand why that solenoid is there. Thanks again!

The inner fender-mounted Ford starter solenoid is a very common fix for hot-start problems, especially when headers are used. Check out this link:

http://www.madelectrical.com/catalog/st-1.shtml

 

[71hcc]

The inner fender-mounted Ford starter solenoid is a very common fix for hot-start problems, especially when headers are used. Check out this link:

Catalog

I can see how that would be a good fix for a hot start problem, but mine was not wired like that. Mine still had the Batt cable running to the starter with all the small wires on the solenoid like normal. The main charge wire out of the Alt. ran to the soleniod on the fender, then it came off the other side of the solenoid and ran to the starter solenoid + post along with the Batt cable. The small wire or energizing wire on the side of the fender solenoid also ran to the starter solenoid. I have pulled it all out and have made my own harness from the Alt back. Thanks for the info though.

 

[71hcc]

I think I should have asked my question differently when I said that I didn't understand what that solenoid on the fender was for. The way it was wired up, it was a switch that isolated the alternator from the battery when the key was off. What I should have asked is, when using a one wire alternator do they have to be isolated from the battery when the ignition is off? I have since changed the whole system back to a internal regulated three wire type. But would like to know for future reference.

 

[Rex S]

My best guess is the other owner had a back-feed problem and the engine wouldn't shut off with the key or the alternator's field stayed energized after turning off the key and kept draining the battery. While the Ford style solenoid would work for a while, they are rated for starting only (short term use) not continous duty.