Engine ground

[ChargerST]

Out of curiosity: why is the main connection of the negative battery post to the engine and not directly to the starter motor and the alternator (= isolated ground)? Those are afaik the only two items that need grounding through the block (and some sensors that ground through the block like oil pressure sensor). Not sure if it would help with possible electrolysis damage if there were direct connections to starter and alternator? Battery needs to be grounded to the body as well (usually done through a ground strap from engine to body).

Or is it a good idea to have a direct ground wire to the starter motor in addition to the engine ground?

Edit: Apparently isolated grounds are a thing in boats and cars with sensitive electronics. Advantages are reduced corrosion, less voltage drop, less electrical noise

 

[gkent]

Your spark plugs need a good ground !!

FWIW, my trunk mounted battery grounds to the bracket between the inner fender and dutchman panel. Up front it grounds from the frame to the block.
The efi and MSD get a seperate ground off the battery.

 

[ChargerST]

Correct! No spark without grounds! A separate ground to the starter would still make sense imo as it has the biggest current draw.

 

[gkent]

That would have cost the manufactures MILLIONS for the extra 3 feet of cable !!

 

[twecomm]

In a "66" Charger w/ 383, Battery negative to front drivers side of engine block, rear passenger side of engine block to firewall. Everything has worked just fine for 59 years. Countless thousands of cars manufactured exactly like this. I would think your concerns are a non issue.

 

[gtx6970]

That would have cost the manufactures MILLIONS for the extra 3 feet of cable !!

This ^

 

[gkent]

You always hear the "woulda, coulda, shoulda" but very few people consider that the MAIN reason every car on the planet is built is PROFIT. And that's a capital EVERY - doesn't matter what the final sales price or what purpose it serves, PROFIT is the goal.