Paul L

Last spring I had a bit of a problem with my starter (1974 L-48). It turned out that the solenoid was a wee bit loose. That was easily fixed and the summer went on OK.

But I had a good look at what was there while crawling about underneath. The front brace was missing; I now have that along with the mounting bolt, solenoid heat shield, etc. But I could not get at the mount hole for the brace as the heat riser valve was in the way. And I was experiencing a lot of back pain. So I wimped out on the install although I have all the parts.





But here is the kicker! That brace and the ground strap to the motor mount are MIA on the engine. So where is this starter getting ground? It starts and runs very well!

TimAT

The ground could be coming from anywhere. Literally, anywhere. Any place the block could even be remotely touching the frame could be the ground. I've replaced several shift cables that were pretty much welded together- they had acted as the ground.

Your MIA ground cable does not have to go in that one place only. It's just where the factory put it.

Paul L

That begs the question if it is not where the AIM says it should be, where the h*** is it??

Paul L

Alan,

As usual you have fantastic pics. But my question is basically since I don't have the motor mount ground cable, why does this car start and run?

I can just put a ground cable on the motor mount and be done with the job. But it looks like ~$80 here in Canada for that cable from the usual USA vendors. Not happy about that price!

I'll try $13.00. Not pretty at 13" but should work.

http://www.canadiantire.ca/en/pdp/br...l#.VvXMunrGDQw

caryb78

well its possible to pick up a ground through the exhaust - engine to pipes through the header bolts to headers to hanger brackets

Paul L

Sorry, I doubt that!

Paul L

May try $9.00 solution.

http://www.canadiantire.ca/en/pdp/br...l#.VvXMunrGDQw

TimAT

Someone may have left that AIM indicated cable off at one time or another- no way to tell. You can get a cable with lugs on both ends in whatever length you want and put it on at any place you'd like.

As I stated before, it's finding a ground somewhere. If not, it would not start.

Paul L

Thanks for listening to me. I am very tired but I know what I have to do in the coming weeks! Learning how to crawl does take some time. My back is very sore.

Paul L

The car starts and has run for many years. I'll do the $9 CTC ground cable this summer.

caryb78

Take a vom and see if the engine gets continuity to the exhaust betcha it does

Paul L

I am not sure what that means. I won't see this car for several weeks after it comes out of storage. Perhaps then I will find out what a vom is!

Hammerhead Fred

Starter grounds to the block.
There are plenty of ground opportunities between the block and the battery - that ground strap simply rules out high resistance routes which could cause poor starter load performance.
With no strap directly from the block to the frame you next likely ground points would occur through the transmission then exhaust to frame.
The transmission grounds to the frame via the mounting bracket bolts as well.
Could also be grounded by the alternator ground back through the harness then on to any other harness to chassis ground point. Motor mounts are good conductors provided the through bolts aren't insulated by the mount finish or rubber flash.

Alan 71

Hi Paul,
Sorry, I mis-understood your question!
I thought you were having an interference problem with so much going on in that small space between the solenoid and heat riser.
Regards,
Alan

Mooser

There's plenty of ground paths to the motor, none as good as that cable, but a bunch of others. There's even that one (smallish) wire that goes to the transmission/engine block bolt just behind the starter.

I wonder if that cable wasn't after attached after the manifold but prior to the heat-riser & exhaust pipe was installed?

One way or another, adding a CT strap anywhere certain isn't going to hurt anything and can only help take some strain off wherever it's currently getting it's gnd.
M

BTW. So you're out of storage now or just planning stages ?

Danish Shark

Solid engine mounts?

John 65

Hi Paul, I used a short black battery cable with the lugs at both ends for the starter to the motor mount horn, works fine. Guessing vom is short for volt meter. Hope your back improves.

TimAT

vom= Volt Ohm Meter/ Check resistance and voltage on the small ones, the larger (read $$$) meters will also do millivolts and milliamps, up to 200A current with a shunt, temperature with a probe, and probably a few other things I'm not thinking of right now.
Handy tool to have.

Paul L

I have one hiding in my Corvette area in the basement.

Paul L

Mooser,

Looks like another 4-5 weeks before I see my 1974 again. We need a couple of good rain washes to get the salt off the road (and my car). Early April promises the old Polar Vortec trick so that rain will not come. A bit discouraging actually.