Ground straps, Make me angry Options

[Geezer914]

I to ran a ground strap from the alternator to the driver side ground in the engine compartment.

[davep]

Added a new 6 gauge cable from the negative terminal to the spot where the coil attaches to the tin work, turns over like a new car.

If you actually fastened the ground cable to the sheet metal engine ducting, then that is a bad thing, and could lead to the fasteners welding to the engine case.
Better is to use the fan shroud as a grounding point, and here is an ideal location.
The alternator grounds to the fan shroud as well. You could add another ground wire from this point to the chassis ground stud near the relay panel. The starter (draws the most current of any device in the car) grounds to the trans case, and subsequently through the engine case to the fan shroud. Thus you have most of the important grounds tied together closely through the best conductors.
I have also had the same problem, as you did, with the battery ground stud not doing it's job. I am afraid that the 50 year old body is just not up to carrying the current that it is tasked with. No matter that the battery ground stud and the transmission ground stud are solid and clean, this does not seem to be enough anymore.

[emerygt350]

Interesting. My mustangs ground strap is on the block. Never heard of electrical pitting in 75 years of mustangs + their relatives.

Those are turbines and electrical generators.

[emerygt350]

Added a new 6 gauge cable from the negative terminal to the spot where the coil attaches to the tin work, turns over like a new car.

If you actually fastened the ground cable to the sheet metal engine ducting, then that is a bad thing, and could lead to the fasteners welding to the engine case.
Better is to use the fan shroud as a grounding point, and here is an ideal location.
The alternator grounds to the fan shroud as well. You could add another ground wire from this point to the chassis ground stud near the relay panel. The starter (draws the most current of any device in the car) grounds to the trans case, and subsequently through the engine case to the fan shroud. Thus you have most of the important grounds tied together closely through the best conductors.
I have also had the same problem, as you did, with the battery ground stud not doing it's job. I am afraid that the 50 year old body is just not up to carrying the current that it is tasked with. No matter that the battery ground stud and the transmission ground stud are solid and clean, this does not seem to be enough anymore.

That looks like a great place. I will see if it is on my shroud.

[dr914@autoatlanta.com]

years ago I forgot to connect the trans ground strap when I was in too much of a hurry as a young PUNK doing a record setting clutch replacement. When the engine turned over slowly, I thought the battery weak, so connected a heavy duty charger. Next thing I see is smoke coming from between the seats. I melted the accelerator cable in the tunnel as the starter used the accelerator cable as the ground. I spend the whole weekeng cutting out the tube and replacing it!

[Superhawk996]

Interesting. My mustangs ground strap is on the block. Never heard of electrical pitting in 75 years of mustangs + their relatives.

Those are turbines and electrical generators.

I’m not saying it’s highly likely just that it’s a possibility with a split case if you were to ground on one side of the case and then pull several hundred amps across the case / bearing / crank interface should that become a path of least resistance

Do what makes you feel good.

[emerygt350]

I see. I moved it to that spot on the shroud. All good. Much more comfortable with that spot.

[Literati914]

regarding the grounding "strap" you guys are adding to the alternator (I like this idea and want to copy) - what is the recommended size for this strap/wire ?

[930cabman]

years ago I forgot to connect the trans ground strap when I was in too much of a hurry as a young PUNK doing a record setting clutch replacement. When the engine turned over slowly, I thought the battery weak, so connected a heavy duty charger. Next thing I see is smoke coming from between the seats. I melted the accelerator cable in the tunnel as the starter used the accelerator cable as the ground. I spend the whole weekeng cutting out the tube and replacing it!

Bet you never made that mistake again (IMG:style_emoticons/default/beer.gif)

[930cabman]

I see. I moved it to that spot on the shroud. All good. Much more comfortable with that spot.

All well and good, BUT, how is the connection between the aluminum shroud and the case and the case with the chassis?

[emerygt350]

So good that my car turns over faster than ever before. Almost scary fast. The original ground strap and the body to battery strap is still there.

[VaccaRabite]

regarding the grounding "strap" you guys are adding to the alternator (I like this idea and want to copy) - what is the recommended size for this strap/wire ?

Thick. Dunno what gage I used on mine. I just took a fat bit of wire and put some ends on it and put it on the car.

Zach

[emerygt350]

years ago I forgot to connect the trans ground strap when I was in too much of a hurry as a young PUNK doing a record setting clutch replacement. When the engine turned over slowly, I thought the battery weak, so connected a heavy duty charger. Next thing I see is smoke coming from between the seats. I melted the accelerator cable in the tunnel as the starter used the accelerator cable as the ground. I spend the whole weekeng cutting out the tube and replacing it!

Now you got me all worried that in my attempts to get the car started I damaged the throttle cable. The cable isn't behaving badly but...

[emerygt350]

regarding the grounding "strap" you guys are adding to the alternator (I like this idea and want to copy) - what is the recommended size for this strap/wire ?

Thick. Dunno what gage I used on mine. I just took a fat bit of wire and put some ends on it and put it on the car.

Zach

Six gauge is what I am using but this isn't on the alternator itself.

[bkrantz]

regarding the grounding "strap" you guys are adding to the alternator (I like this idea and want to copy) - what is the recommended size for this strap/wire ?

Thick. Dunno what gage I used on mine. I just took a fat bit of wire and put some ends on it and put it on the car.

Zach

Six gauge is what I am using but this isn't on the alternator itself.

Remember, the longer the wire the fatter the gauge, for the same amount of current.

[emerygt350]

Yeah, this is pretty short, 16 inches I think. The starter cable is a 4 gauge if I remember correctly. I am going to pull the transmission ground strap next chance I get and clean the crap out of it and the connections. Leaving my additional ground in though. It was so nice hopping in the car this morning on the way to work and hearing it spin that fast. It was almost scary. I have a point higher compression than stock too. My voltage regulator/alternator is working better as well. I just checked and it's dead on 13.75 steady. Oh, and my fog lamps are working again, not sure what's up with that. If I don't have to do the LED upgrade blue/white ground hack I would be happy.

[StarBear]

regarding the grounding "strap" you guys are adding to the alternator (I like this idea and want to copy) - what is the recommended size for this strap/wire ?

Thick. Dunno what gage I used on mine. I just took a fat bit of wire and put some ends on it and put it on the car.

Zach

@vaccarabite
Zach; I like the fan shroud to chassis ground idea. Can we chat when you’re here on the 14th?

[914_teener]

I see. I moved it to that spot on the shroud. All good. Much more comfortable with that spot.

All well and good, BUT, how is the connection between the aluminum shroud and the case and the case with the chassis?

Don't think the fan shrouds are aluminum.

[Literati914]

Don't think the fan shrouds are aluminum.

I was thinking the same, they are magnesium .. but then so is the tranny case - so I guess it doesn't matter.

[davep]

All well and good, BUT, how is the connection between the aluminum shroud and the case and the case with the chassis?

The electrical connection from the fan shroud to the engine case, and the engine case to the transmission case should be excellent, much better than the chassis itself. That is how the alternator is grounded to the chassis in all 914's.

There was some talk of current through bearings and gears, but IMHO that is totally insignificant. The fan housing bridges the two engine case halves and the case bolts do the same. If you keep the battery and transmission ground straps in place, then I see no possibility of problems