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Post by mongoose on Sept 23, 2010 7:41:45 GMT -5
What's the purpose/benefit of the ground strap attached to the back side of the passenger side head and the firewall?
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Post by bubbasz1 on Sept 23, 2010 8:03:03 GMT -5
It grounds the body to the electrical system, Negative cable goes to engine block, ground strap transfers ground to body.
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Post by Deleted on Sept 23, 2010 8:38:10 GMT -5
It grounds the body to the electrical system, Negative cable goes to engine block, ground strap transfers ground to body. This is, in fact, the body ground location. It serves other purposes also. A few things to remember, never replace with single, or multiple strand, insulated wire. ALWAYS use BRAIDED non insulated material, COPPER. The reason for the braided is that it is a superior R/F dampener, it tolerates vibration, heat, and stress much better than single or multiple strand. This strap not only grounds your body accessories, but turns your sheetmetal in to an R/F shield. Your alternator, ignition, blower motor all try and screw with your radio, this is designed to damper this. You`ll notice often this connection is burnt, or severed,it`s usually from a bad main ground to the block, or block to frame.
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Post by rickman on Sept 24, 2010 13:45:58 GMT -5
I had a '69 442 with a ton of electrical problems until I connected them! Positive cable had interior corrosion, both cold and hot start problems, Even the radio and horn acted up! Finally found them flat against the firewall - had forgot they were even there on olds. Previous owner musta forgot, too.
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Post by RAM Z on Sept 24, 2010 16:04:51 GMT -5
Couple months ago I got in mine, it cranked weird, and smoke poured out from under the hood. Got out and watched while my wife cranked it, small black ground lead on the neg cable that runs back to the inner fender wasrubbed raw on the steering box and was eating itself. Someone figure that one out for me. Cut it off and it started right up.
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Post by mongoose on Sept 25, 2010 6:02:09 GMT -5
...small black ground lead on the neg cable that runs back to the inner fender wasrubbed raw on the steering box and was eating itself. Someone figure that one out for me. Cut it off and it started right up. I don't think I've ever seen a second wire running off the negative battery cable. Is that an original factory thing? Your car is restored completely original isn't it?
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Post by Deleted on Sept 25, 2010 8:05:37 GMT -5
Couple months ago I got in mine, it cranked weird, and smoke poured out from under the hood. Got out and watched while my wife cranked it, small black ground lead on the neg cable that runs back to the inner fender wasrubbed raw on the steering box and was eating itself. Someone figure that one out for me. Cut it off and it started right up. I`ve been watching for a reply since just after you made the post, I`ll give it the rest of the day before I chime in
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Post by bubbasz1 on Sept 25, 2010 9:38:20 GMT -5
Couple months ago I got in mine, it cranked weird, and smoke poured out from under the hood. Got out and watched while my wife cranked it, small black ground lead on the neg cable that runs back to the inner fender was rubbed raw on the steering box and was eating itself. Someone figure that one out for me. Cut it off and it started right up. I`ve been watching for a reply since just after you made the post, I`ll give it the rest of the day before I chime in I'll take a shot at it. First the question of whether the 65 came with a separate small ground off the negative terminal to the frame or body, don't know. Second why did it smoke the wire then work after the wire was removed. Electricity is lazy, the separate ground wire shorted on the steering box or whatever and the current took the easiest route back home which was the smaller partially grounded wire, it overheated and melted. Remove the small wire and it went back to grounding through the larger negative ground and everything went back to normal.
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Post by RAM Z on Sept 25, 2010 9:59:29 GMT -5
The original and repro neg cable has a small black wire that runs back from the head to the inner fender.
Wire runs from the head, so the battery is already grounded thru the heavy cable to the head. The small wire is grounded at the inner fender, it rubbed at the box and was grounding there instead. So why did it burn? Ground at the fender or the box, same thing right??
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Post by slowolds on Sept 25, 2010 13:07:22 GMT -5
I thought the small ground wire was to help the front end electrical stuff (headlight, horns, etc) with grounding. I have always used them.
As far as why yours melted, I would say your connection to the head is not as good as you think.Electricity is lazy and hates resistance. If there is resistance along the head path it tries to run it all through the small wire (path) which can't handle the current.
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Post by Deleted on Sept 25, 2010 19:34:22 GMT -5
I thought the small ground wire was to help the front end electrical stuff (headlight, horns, etc) with grounding. I have always used them. As far as why yours melted, I would say your connection to the head is not as good as you think.Electricity is lazy and hates resistance. If there is resistance along the head path it tries to run it all through the small wire (path) which can't handle the current. These cars did have the aux.ground to the inner skirt, just ahead of the steer box. Reason for it was to serve as the ground circuit for the front lights etc. In jasons case the cause, and effect are obvious, along with the question, why did it start after you cut the ground jumper?? The cause was a bad connection at the block from the neg. of the battery. There is no other explanation,period! What happened is, you turn key to start, there was first the solenoid being energized, no problem for either the main ground to the block, even with a bad connection, or the acc. jumper to the skirt. But now that the solenoid is closed, the two terminals are asking for mega amps, the little jumper that had less resistance than the main, couldn`t handle the load, fried !! Now the large cable to the block is connected, but because of corrosion, paint, or just loose, has a high resistance, but is still in the circut, when the high amperage is drawn thru the only path it has, it will clear the route by actually fusing a link the size it needs, or, open the circuit by melting. Did you ever weld with car batteries, ever touch jumpers together, hell of an arc. The engine block, in this case, is nothing but an extension of the negative battery cable terminating at the starter. Gotta complete the circuit !!! Here`s one for ya! this was brought in to me for repair in the early 70`s Customer: Tried starting car, turned over like dead/low battery, smoke from under hood, under dash. I opened hood, checked battery connections (battery located pass side) noticed ground jumper to pass fender was blistered,most insulation melted. Further inspection located antenna cable melted, burnt in half. Same culprit, different reason. The car had been in an accident, radiator support repaired, battery and neg cable replaced, fender replaced. for one reason or another ground cable was never cleaned properly to the block, the fender before installation was cut in with primer/paint, then mounted and finish paint applied. The combination of all that new paint, and loose ground to the block, led to high resistance at the main ground, no grounding of the fender to the body, other than thru the aux. jumper from the neg. cable, and the antenna ground to the radio, from the radio frame thru the dash/ cowl metal, to that poor little strap on the back of the engine head. So back to the original question that started this post "What`s the purpose/benefit of the ground strap" YOUR CAR CAN`T LIVE WITHOUT IT !!!!!!
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Post by bubbasz1 on Sept 25, 2010 20:43:15 GMT -5
Postcar, That's almost what I said You basically killed that problem, how long did it take to type that all up, all afternoon. HA
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Post by Deleted on Sept 25, 2010 21:34:34 GMT -5
Postcar, That's almost what I said You basically killed that problem, how long did it take to type that all up, all afternoon. HA "That`s almost what I said" People aren`t looking for "ALMOST" " You Basically killed that problem" That was my intent "How long did it take to type that all up" I typed with my single pointer finger, till I figured EVERYONE would understand. O.K. nuff said, I`ll keep quiet FOR AWHILE
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Post by mongoose on Sept 26, 2010 5:22:43 GMT -5
Ok... there's plenty of talk about path of least resistance, and the handful of various ground straps and wires throughout the electrical system. Definitely information to contemplate... I got my '65 in 1985, and it didn't have the block to fender skirt ground then, so I never knew it should have one. Fortunately the front circuits found a ground another way, because I've never had any issues I can recall with them. But it seems like something I should add. I've had problems over the years with the firewall to ground strap with the wire braid pulling free from one of the connectors. Occasionally I would take it off, and try to spread the "tangs" and reattach the braid, but that hold was always temporary. As you know, that strap is roughly 1/4"-3/8" wide. Recently while I was picking up some stuff at NAPA, I asked about a replacement ground strap, which they had in stock. But this particular strap is much larger, probably close to a 2" wide braid. That seems fine until I start thinking about this whole path of least resistance stuff. Am I introducing potential issues using this larger strap, which is theoretically lower resistance than the original, causing more circuits to ground through the dash and firewall than was originally intended? And would that be bad? I'm thinking of the burned radio antenna example... While on the subject of electrical circuits (I'm going to somewhat hi-jack my own thread), where is the grounding circuit for the rear taillights? Over the years I've had trouble with primarily the right rear tail light. Sometimes it works, sometimes only the brake light works, sometimes when I step on the brake the taillight goes dimmer. I replaced the bulb socket, and it seems to work for a short while, then the symptoms returned. I added a ground wire between the socket flange and the metal housing for the taillight bucket, and that seemed to help more... but the symptoms would still crop back up. Thoughts? I'm sure there are plenty of them... That's what makes this such a valuable forum.
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Post by bubbasz1 on Sept 26, 2010 8:54:28 GMT -5
Basically I don't think you can have too many grounds/or too much ground. Most electrical issues are caused by bad or improper grounds, your taillight issue could most certainly be from a poor engine to tub ground as that is where the ground would most likely come from.
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Post by mongoose on Sept 26, 2010 20:39:11 GMT -5
What guage is the engine to inner skirt wire? Does the eyelet on the engine side go behind the same bolt as the battery ground? I assume this ground is an insulated wire (the reference to melting the insulation) and not a gound strap.
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Post by slowolds on Sept 26, 2010 23:54:44 GMT -5
as to the tail light issue--- I put a different frame under my '65. I cleaned up everything(wire brushed the frame, rust encapsulator etc.) I could touch. The body got a new trunk and again, everything I could get too I cleaned and painted. All new body mount bolts as well. I could not get my tail lights to work without an extra ground from each tail light housing to the body. (I did put in new sockets)
The only thing I can think of is I painted way more things and with a thicker coating than the factory did in '65.
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Post by BR[] on Sept 27, 2010 6:49:31 GMT -5
If you are using the factory or factory style tail light sockets, they can cause issues. Since they are made of plastic they have a small metal tang that has to make contact with the tail light bucket. It can be very hard to get a good contact and it's often easier to go to Advance or Auto Zone and get the generic sockets which have metal tangs around the entire perimeter that will make a solid contact. If you want it to be 100% factory then you will fight this issue or run a hidden ground.
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Post by mongoose on Sept 27, 2010 7:48:44 GMT -5
Sounds good. I think the socket I replaced was still the single tang style. The car is definately not original, so changing to a part that is more effective/reliable is not a problem.
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