Braided Ground Strap O 300

[MoonlightVFR]

I did research on the forum about ground straps.

Noted that the IPC Sept 1956 did not have illustrations on grounding straps. PN 0551000-50

A braided batt cable comes down from Neg term and bolts direct to firewall. I understand. Neg Grn.

What I really want to discus in this post is a very small braided cable that appears to loop around engine mount. It is so small I have long thought of it as a joke. It turns green and I clean with a baking soda solution.

My thought has always been to replace it with something more substantial say like a motorcycle braided strap. But something stops me like "How to" - there is an engine mount involved!

Surely this tiny strap has nothing to do with starting the engine.

What is this tiny strap? What is it's true function? Is it even mentioned or illustrates in C170B parts or maintenance literature.?

What would happen if just disappeared?

What ever it does it has been on the job for 62 years.

[Bruce Fenstermacher]

Yes that tiny ground strap (and the others) can have lots to do with starting your engine.

A short story. A friend's 170 was always difficult to get the starter to turn over the engine at a speed for good starting. When things were perfect it worked OK which of course set in procrastination for a fix. Finally after years and a new battery, frustration set in and trouble shooting started. Turns out the only ground to the engine was the throttle cable case. All others had been removed at engine overhaul years earlier. As you might imagine the throttle cable was not a very good ground offering lots of resistance.

You do not have to replace the ground straps you have. You do not have to fool with the engine mount. And you do not have to use a braided strap just because it is a ground. A stranded cable of suitable size like the positive battery cable can be placed from the ground lug at the firewall to the engine. A suitable connection on the engine might be a stud or bold used to hold the starter or generator to the accessory case. I also like to see a ground wire run from the same spot on the engine to the base of the regulator.

Proper adequate grounding is often overlooked. Unless you go to extremes, you can not have to many grounds wires

[bagarre]

I think 81D had an extra braided ground strap that went from a starter bolt to the firewall.
Its not original but I plan to do the same with 95D.

[Bruce Fenstermacher]

If you must have a braided strap, O'Reilly Auto Parts list a 26" strap which they claim to be 4 gauge for $20. I don't know if 26" is long enough from the accessory case to the fire wall but I'm thinking it is.

http://www.oreillyauto.com/site/c/detai ... &ppt=C0061

[daedaluscan]

I put a napa braided strap from the battery negative to the case. Dramatically improved starting and charging. It was about 12".

Three out of four of the motor mount straps were broken.

[170C]

Charlie, where on the case did you attach the grounding strap?

I ask because my starter isn't turning the engine like it did in the past. Ck'd the battery and it shows to be ok. Thinking maybe my starter needs overhauling, but before doing so I need to check MY grounding straps and I may get a napa one and see if it makes any difference.

[N2625U]

Years ago I was having problems with starting and checked the ground cables. Back in the '70's and old crusty A/P told me that it seems most electrical problems turn out to be the ground connection. They had a lot of corrosion cleaned them and that did the job.

[daedaluscan]

Charlie, where on the case did you attach the grounding strap?

I ask because my starter isn't turning the engine like it did in the past. Ck'd the battery and it shows to be ok. Thinking maybe my starter needs overhauling, but before doing so I need to check MY grounding straps and I may get a napa one and see if it makes any difference.

I can't really remember, it was a bolt near the rear left motor mount. Ill take a look and post a picture.

[MoonlightVFR]

Bruce Thanks for the Pix . I will try O'Reilly's.

Your comment , "can't have too many grounds"
Reminds me of career ( 50 yrs) GM mechanic who said there were four to six grounds on on their new ('95) engines. Northstar had a ground for transmission!! Was I ever surprised. Modern electronics is the reason.

Could we as a Group develop a new revised standard for grounding Starter motor and other needs?

Official printed literature for these Cont engines comes up a little Short for such an important subject.

Regards

[bagarre]

So long as the original ground straps are in place and in good repair, they are more than sufficient for the starter. That's probably why TCM gave no further guidance.

But, they are difficult to replace or even clean up in practical application. I guess they didn't take into account a 65 year design life

The starter needs to be grounded, not the motor. The original path was from the starter to a stud (the gasket insulates the starter from the block), to the block, to the motor bed mount to the ground strap to the motor mount to the motor mount bolt (rubber mounts on the motor mount), to the firewall, to the ground strap, to the ground.

Mine will be from the stater to the ground strap, to the other ground strap to the battery.

I plan to stay close to if not the same gauge as the ground strap to the battery and run it from a stud on the starter back to ground strap on the firewall. You can't get much better than that. The only more direct route is back to the battery but I'd rather not stack terminals on the battery.
The strap the Bruce posted is perfect for this but a length of 4 or 6 gauge wire and two terminals would be just as good.