Engine & Battery Ground

[hrosenthal]

Can I use the same bolt on the frame to ground both the engine and the negative terminal of the battery?
I am locating the battery under the hood, so it would be one less hole in the chassis.
If anyone has pictures of how the engine ground looks, I'd appreciate it.
Thanks

[DaleG]

I would think that would be optimum. I did that, plus added an additional engine ground wire to the chassis on the other side of the engine.

EDIT: Did more or less the same as Edward below as to location, but welded-in grounding bolts at various locations on the chassis.

If anyone is going to send their chassis out for powder coat, mark locations and bolt size on the chassis; powdercoaters will usually be able to weld them on for you. Then all you have to do is clean the pc off the bolt threads and nuts.

[Bren]

I would think that would be optimum. I did that, plus added an additional engine ground wire to the chassis on the other side of the engine.

I agree. The fewer grounding points on the vehicle, the better. The motor is the best place considering the high amps going through the motor (e.g., starter, ignition).

[edwardb]

This isn't the best picture, but it's easier to see without the engine in place. With the front mounted battery, took the battery ground to the frame on top of the 4 inch tube. I tapped 3/8-16 threads and cleaned the powder coat to bare metal. I also sanded a 4 inch dia curve in the bottom of the lug using a sanding drum. This made sure the lug had full contact on top of the 4 inch tube. Then put the engine ground lug on top and bolted in place. Since this picture was taken, engine is in, and I have a 4 awg cable in that lug going to an unused 3/8-16 lug on the block behind the alternator. Not pictured, I have a second engine ground going from one of the starter mount bolts to the frame. That one I put into the side of the engine mount and it's held with a thru bolt and lock nut. This is a carb'd engine, so should have more than adequate ground.

http://i867.photobucket.com/albums/ab234/edwardb123/Factory%20Five%20Mark%204%20Roadster%20Build/Electrical/IMG_2393_zps3b47ce87.jpg (http://s867.photobucket.com/user/edwardb123/media/Factory%20Five%20Mark%204%20Roadster%20Build/Electrical/IMG_2393_zps3b47ce87.jpg.html)

[DaleG]

This isn't the best picture, but it's easier to see without the engine in place. With the front mounted battery, took the battery ground to the frame on top of the 4 inch tube. I tapped 3/8-16 threads and cleaned the powder coat to bare metal. I also sanded a 4 inch dia curve in the bottom of the lug using a sanding drum. This made sure the lug had full contact on top of the 4 inch tube. Then put the engine ground lug on top and bolted in place. Since this picture was taken, engine is in, and I have a 4 awg cable in that lug going to an unused 3/8-16 lug on the block behind the alternator. Not pictured, I have a second engine ground going from one of the starter mount bolts to the frame. That one I put into the side of the engine mount and it's held with a thru bolt and lock nut. This is a carb'd engine, so should have more than adequate ground.

http://i867.photobucket.com/albums/ab234/edwardb123/Factory%20Five%20Mark%204%20Roadster%20Build/Electrical/IMG_2393_zps3b47ce87.jpg (http://s867.photobucket.com/user/edwardb123/media/Factory%20Five%20Mark%204%20Roadster%20Build/Electrical/IMG_2393_zps3b47ce87.jpg.html)

Boy, that's a lot tidier than mine.

[hrosenthal]

I got it done. Not as nice as this, but completed nonetheless.
One thing I'm confused about is connecting the ground wire to the engine mount.
Why would FFR have that step done so late in the build? It would have been much easier to connect the wire before installing the engine.
I had a hell of a time getting through such a simple task.