1960 engine harness fire

**John B.** · July 4, 2013, 03:22 PM

Re: 1960 engine harness fire

I had a seemingly spontaneous fire in my wiring harness on my 60. Turned out that a positive lead melted through and the entire length of the ground wire got super hot and caught fire. The whole thing happened in a few seconds while I was working on the car. The wire that was the culprit was a bit too long and touched the exhaust manifold. Wiring harness was from Lectric Limited as well. I shortened the melted wire and replaced all of the effected ground wires and everything has been working well.

**Robert S.** · July 9, 2013, 10:33 PM

Re: 1960 engine harness fire

It's a 60, learn how to do the twist. Leave the positive battery cable loose and twist off when you finish driving and twist on next time you drive the car. Resetting the clock is a pain, but easier than what you have to do now.

**Terry M.** · July 9, 2013, 10:41 PM

Re: 1960 engine harness fire

The only car that is in the garage that has the battery connected is the 2008. EVERY thing else is disconnected. Batteries are a tremendous source of power -- as they are intended to be. Don't let the magic smoke get out.

**Jef S.** · July 10, 2013, 06:48 AM

Re: 1960 engine harness fire

Thanks for the replies that is basically the solution I have come up with I have ordered two knife blade kill switches one for my 60 one for my 64. I was hoping for a little more technical advise. I have sent the generator and starter out to have them gone through and will replace the voltage regulator. And new Lectric Limited wire harnesses. There is no damage to any battery wires but I guess that is where it had to have started the other wires are so far gone it is impossible to detect any origin. Thanks again

**Jim L.** · July 10, 2013, 07:20 AM

Re: 1960 engine harness fire

Originally posted by Jef Steingrebe (52553)

Anyway the engine harness and generator to voltage regulator harness burned due to overload. The generator was too hot to touch regulator was not hot at all. Any thoughts as to cause?

What you've described in these two sentences would be consistent with the cut-out relay in the Voltage regulator failing to open when the engine was shut off.

In such case, the full battery Voltage would be applied across the generator armature and a lot of current would flow in it and in the wiring that connected it to the battery.

Jim

**Richard M.** · July 10, 2013, 07:36 AM

Re: 1960 engine harness fire

Jeff,

For the main feed to the ammeter to overload could have been caused by several things. The fact that the generator harness melted leads me to believe that the regulator may have stuck on, constantly energizing the generator. This would keep it in constant charge. I had a similar fault on my '59 many years ago. The regulator was stuck on. It fried the generator harness, overloaded the generator and burned out the armature in the generator. The telltale was when driving the car the previous night, the lights seemed extra bright but it didn't register. The next morning I smelled something and when I opened the hood the generator harness was burned. New regulator, generator, harness and all was fixed.

You may want to open the regulator and see if any contacts are welded stuck. As you're planning. replacement is a good idea.

One other item to check is your ammeter. Since all load goes through it, make sure your connections are tight on the studs, and the studs are properly insulated from the meter case. Any loose connections can cause high resistance and high current. I recently pulled a ammeter from a '60 and as you can see below in the pictures there was a bad connection, causing arcing inside the meter, so extreme it was burning the meter case paint on the inside.

To prevent future burnouts, and to ensure your electrical system is okay after you get the charging items replaced you may want to consider this. When you get your new engine harness installed, you can temporarily(or permanently if desired) add a 30 amp fuse to the harness where it connects to the starter battery stud. You'll have to add terminals to the fuse holder and fasten using short bolts and insulate with heat shrink and vinyl tape. It may not look pretty but it would be an extra level of protection until your confident the electric system is working properly. Just make sure the fuse holder and extra wire lengths are insulated and positioned away from exhaust pipes etc.

Another option is to add the fuse at the black feed at the ammeter underdash. This wouldn't protect the black wire from solenoid stud to the meter, but any overload from the meter onward would be protected. This is where I usually add the 30 amp fuse. Easier to reach under the dash if needed as well.

Fusible links could be used in place of fuses, but more difficult to replace when your on the road far from home.

Rich

Attached Files

**Thomas H.** · July 10, 2013, 12:03 PM

Re: 1960 engine harness fire

Fuses are a great thing to use to protect your wiring from a short circuit or over current situation. But..... Fuses, just like circuit breakers, are supposed to be the weakest link in the wiring system. If you put a 30 amp fuse at the battery, it will provide protection for all of the wiring down stream that capable of handling 30 amps or more. Smaller gauge wires (higher number) that can not handle 30 amps will then become the weakest link. You could have a circuit failure where the current draw was 20 amps through a small gauge wire cause a fire and never blow the fuse.

Working on my 60 I have found many points where the wire gauge is stepped down to a smaller size. If you have a 20 amp fuse feeding a circuit with 14 gauge wire and it later gets stepped down to 16 gauge, that section of 16 gauge will get pretty hot before the 20 amp fuse will blow.

Fuses provide good failsafe protection, but only in systems that are wired correctly.

Tom

**Richard M.** · July 10, 2013, 03:59 PM

Re: 1960 engine harness fire

Originally posted by Thomas Hoyer (44463)

Fuses are a great thing to use to protect your wiring from a short circuit or over current situation. But..... Fuses, just like circuit breakers, are supposed to be the weakest link in the wiring system. If you put a 30 amp fuse at the battery, it will provide protection for all of the wiring down stream that capable of handling 30 amps or more. Smaller gauge wires (higher number) that can not handle 30 amps will then become the weakest link. You could have a circuit failure where the current draw was 20 amps through a small gauge wire cause a fire and never blow the fuse.

Working on my 60 I have found many points where the wire gauge is stepped down to a smaller size. If you have a 20 amp fuse feeding a circuit with 14 gauge wire and it later gets stepped down to 16 gauge, that section of 16 gauge will get pretty hot before the 20 amp fuse will blow.

Fuses provide good failsafe protection, but only in systems that are wired correctly.

Tom

Tom, I agree with your comments. Valid points. On a C1 there are many other circuits with no fuse protection. Namely the clock, cigarette lighter, horn relay/horns, ignition circuit, wiper motor, acc feeds for instrument gauges. I usually add a 15 amp fuse for the lighter, and another 15 amp for the clock(original type). Both of those items have failed in the past in my experiences and destroyed harnesses. It's unfortunate the factory design didn't protect all circuits originally.

The 30 amp at the source I suggested is mainly to protect a serious overload, like what happened to Jeff. I suspect in his case it would have protected the wiring and prevented the fire. I suggested it for him as a level of protection when he reinstalls his new harness and charging system, just in case some other item is at fault, like the ammeter.

Rich

**Philip P.** · July 10, 2013, 05:06 PM

Re: 1960 engine harness fire

I think the regulator is probably the problem also. I installed a switch and circuit breaker in the line that goes from the starter to the ammeter(12 guage black wire), the switch shuts all the power off to the car when not in use (poor mans anti-theft) and the circuit breaker will (or should) shut the power off in case of a big time short in the car like what happen to you.
Phil

**Jef S.** · July 10, 2013, 07:59 PM

Re: 1960 engine harness fire

Thanks for all the help I will install an inline fuse along with the battery kill switch. My cigarette lighter is functional but I never use it, the wiper motor also works or at least it did before the fire, but again I never use it the car doesn't really see any rain anymore. LOL

1960 engine harness fire

1960 engine harness fire

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