MTFCA Forum

I tried to start my t today and when cranking it with the starter, I noticed the ground wire smoking and when I go out to look, it had melted. Does anyone know a cause for this problem?

Thanks in advance, Jacob Mangold

Is it a 6volt system and are you using a No. 1 wire? Standard wires for 12volt systems are No. 2 wire and cannot handle the amperage.

I have seen this on many cars T's to modern it usualy means your engine is not grounded well. I never rely on the motor mounts to ground the
engine. Once had sparks coming out of the front motor mount because there was not a good ground on the engine. I run a 00 cable from the
frame to a pan bolt. My neighbors T bucket would not crank when he first finished it. while crangking on it I noticed the SS brake line on the
rear axle was glowing orange. For some reason the $40 brake hose was not a good ground. Remember the ground is 50% of the circuit in any
D C system. And probably the issue in 50% of the problems.
Craig.

Jacob,
(From your post 4/14/23): "I am running 12 volts to the starter. The battery cables are the correct one however, I do not use the braided ground wire."
I agree with others that suggest you have the wrong ground cable for 6V and or whatever you are using at the moment. Now that you have proven the engine will run, my recommendation at this point is to go thru the entire electrical and mechanical systems and get them right, including putting on the correct hogs head, and installing a rebuilt 6v starter, then you will have a reliable and enjoyable model T. Until you do that, you will continue to have disappointments and surprises.

I would leave the starter rebuild to a professional with model T starter experience. Rebuilding a starter takes special equipment, knowledge, and skill that most of us do not have. Since your starter actually turns over, the problems will be a combination or all of the following:
1) damaged electrical terminal post
2) bad bearing
3) bearing lube
4) dirty commutator
5) worn commutator
6) full of crud
7) worn brushes

I would expect all 7 problems to exist with a 100 year old starter. And those are just the common and simpler problems.

Poor connections, junky starters, cheap, undersized batteries, and dime store cables:
These things cause issues with any system.
They can be especially problematic with a 6 volt system, but they will cripple any starting system.
A starter in poor condition will often draw far more current than it should.
A 6 volt system in good condition will give excellent service.

It's a good idea to provide a reliable, high current engine to ground ground cable on any vehicle that doesn't have one.
It's never a good idea to crank any engine with the electic starter for more than 15 to 20 seconds at at time without allowing the starter to rest for a minute or two to cool off.

Slamming a 6 volt starter with 12 volts and grinding on it for extended periods will destroy a good starter.

If your engine does not start within 10 seconds or less of cranking with the starter, stop cranking it and find out why it will not start.

There is no magic in 12 volts.

As Craig Leach mentioned, he uses a 00 size cable as a ground . 00 or 2/00 size cable is more than adequate to carry the amperage needed for the 6 volt starter on both positive and negative cables. Sometimes there is confusion in stating the actual size of the cable but you will find when you inquire that size 2 cable is a lot thinner than the 00 or 2/00 cable . In practicality, size 00 and 2/0 cables are the same size and amperage capacity rating. Size " Two - Zero " has been written as " OO " or " 2/0 ". ........ Cables used on 12 volt systems are of a lesser diameter.

It could be your switch. If the switch is broken and when you push the button, it connects to ground instead of to the starter cable, you you would have a direct short to ground. The insulators on the posts for the switch sometimes are cracked or slip to one side causing this condition.
Norm

It’s probably not the switch because I have a new modern one from langs but it is more likely the cable because the system was originally 12 volts but I did not look to closely at the ground wire as it did the positive wire. I will look today.

Thank you guys, Jacob Mangold

What was the gauge of the wire that melted? if 1 or 2?

12 Volt cables are normally 4 Gauge.

Most of the cables you buy for a Model T will be 2 gauge when 0 Gauge was the normal size.

The correct size cables are hard to find now.

The heat at any of the terminals or on a cable will tell you you have a bad connection or a cable that is too small.

Would it be safe to state that ground and positive electrical cable for the Model T can be mage in house using electric welding cable?
https://weldguru.com/welding-cable-size/

I took a look at one I took off the car when converting it to solely 6 volts because the other one kinda melted and it said it was 6 gauge. I found a 00 battery cable to use in my garage. What are 6 gauge battery cables used for?

Thanks for the help, Jacob Mangold

Ye Gads! Why are we talking wire gage and welding cable wire?! Stop backwards engineering/reinventing the wheel. A proper 6V braided ground strap at a length for a model T or TT is available from the usual vendors. Here is one:
Chaffins Garage
518 N. Spring St.
Lake Elsinore, CA 92530
951-226-7331
chaffinsgarage.com
open 8-5 M-F

Battery Ground Cable 6", part number: 5049B
Battery Ground Cable 10", part number: 5049C

As others have already stated, a hot ground strap is an indication of other problems too, most likely a bad starter. Just replacing the ground strap will not necessarily solve your problem.

6 gauge cable is suited for a small riding mower with a12 volt system. Cheap cables often have thick insulation and a skinny conductive core.

I would suggest that no one knows the state of the starter good/bad, other than it is functional as it has started the car in the past for this young man...a young man who is learning...

The starter did not overheat the #6 cable...the #6 cable overheated the #6 cable

since the starter takes about 150A at a brisk spin and over 500A near stall speed, there is zero question as to why the cable melted.

Ye Gads! Why are we talking wire gage and welding cable wire?! Stop backwards engineering/reinventing the wheel.

Well, From my limited owing a Model T Ford, I have found wire gauges to be standard. As for backwards engineering, I can say that some folks don't like to get their hands dirty.

Reminds me of the time I went into a national parts dealer looking or sparking plugs for an UR Audi Quattro...Bosch equipped I believe...the fellow behind the counter...could not find the Bosch sparking plug on the computer screen and informed me that Bosch of Germany did not make sparking plugs for an Audi of Germany. If it isn't on the computer it does not exist?

I hope the two pics attached will give a sense as to the size of wire being discussed. Yes with backward engineering the welding cable will carry the 6 volts DC, 100 to 200 amp current to start the car.

Using Number six cable....there may be a problem.....

The starter is freshly rebuilt and the ground cable has been taken care of. It does not become scorching anymore and the starter was able to start the car without any hiccups. Also, I know that the engine is quite easy to turn over and start by hand so I don’t need to use the starter all the time.

Good for you, Jacob

Keep the good news coming