Kinda funny , I have spent most of my life wiring cars trucks and very large boats . Built several harnesses from scratch for very high end cars . And have never really thought about power doing anything other than being used up at its source . So this thread has shed some light on basic flow . Sent from the frozen North
I wired my first T Bucket myself and it took a couple days. Everything worked, but it was a hack job. My problem was and sometimes still is, lack of patience. This time around, I'm promising to take my time and plan ahead.
For someone wiring up a car from scratch and wanting to have a clean steering column with no turn signal arm on it or not wanting to run the turn signal wires up the column. I have used the electronic turn signal module from Speedway on my last two builds. All it takes is two push buttons that can be mounted anywhere handy. It gives you turn signals and 4 ways and is easy to hook up. The switch can be mounted anywhere under the dash out of site. I mount mine beside the fuse box.
An electrical circuit is also like a water line in that if you have a restriction in the line the flow is reduced. A restriction in an electrical circuit may also cause unwanted heat at the restriction though. Over the years bad grounds have been the main electrical trouble shooting issue I've run into on owner worked on it himself rigs. Had a guy replace his alternator, starter and battery only to find out that the end of the ground strap from the battery to the block was loose after I told him he needed to check his ground connections before doing anything else. Ended up that the bolt that held the cable end to the block was loose enough so it wasn't making good contact. I lost track of the number of "won't crank after rebuilt" engines I have looked at that had the ground strap right over several coats of engine paint with the bolt hole also well painted because the owner didn't want to scratch is pretty engine paint. Best pain in the butt electrical issue was my buddy's 29 Model A that was wired by a guy many PNW rodders know with ALL RED wire, every wire in the car was frigging red. A real pain in the butt to troubleshoot on the side of the road on the way to a rod run. As others said color code the wiring and use the same color the whole frigging length of the run even if it means going to the store and buying another role of wire.
current flow....yeah....but the ground isn't the only place for fun problems. I remember someone replace the charging and starting system twice on a car...I asked what the ammeter said, he said it didn't work right. Doh! the current was not flowing from the alternator back into the battery, because the ammeter was busted.
Just a funny story about the lack of an engine to frame ground. I had built an old Bomber car, ( a stripped down stock car with a 4 post cage) for the local dirt track. I put the motor, trans in etc and was ready to fire it up. The gauge panel was a piece of sheet metal with a toggle switch, a push button, an oil pressure gauge and a temp gauge. As I was cranking on the starter, I noticed it was real slow, and I saw the little connector between the temp gauge and the block was glowing red, just like a little heating element. That was the only ground I had, and was fast burning itself up. I had wrongly "assumed" that everything would ground through the motor mount bolts, just like Bruce mentioned in his GM story. Yes, I run a separate ground wire from the frame to the block now.
You can do this, but it's generally not a good idea. A lot of wiring issues are caused by builders and/or harness vendors 'saving money' by using undersized or barely adequate wire size. If more people would wire their cars with nothing smaller than #14 and use more #12 and #10, a lot of these issues would go away. Bruce Lancaster has the right idea.... and shows that the OEMs are just as guilty with cutting corners in places they shouldn't.
Agreed! I remove these plastic sleeves and solder the connections. Usually I'll use a colored shrink sleeve (same color as the wire). Have different sizes available. If you can plan ahead, 1/2" long every few inches of large diameter tubing make a tidy wire loom. DC electricity is a circuit! The negative post of a battery has a surplus of electrons, the positive post has a deficiency of electrons. ( some engineers see it the other way around) The electrons always try to go to the post that has fewest. Any time you close a circuit (engage a starter, switch the headlights on, etc.) you make those electrons go through that device and use those electrons to make it work. BUT, these electrons need to get back to the battery. The electrical device needs to be grounded! When both posts have the same amount of electrons, the battery is dead. The generator does the majority of the work: it supplies current (electrons) to electrical devices and keeps the battery at full state of charge. Really, the battery is needed to operate the starter and to provide sufficient to the ignition during start-up.
If an old car is a bit ratty, all the grounds are wonky because they are attached through rust and grease. If the car is restored and finished, all the grounds are bad because they are screwed to 6 layers of polished paint. Law of physics there, you can bank on it.
Anybody in the midwest that knows what they are doing wanna come lend a hand, teach and make a few bucks? I haven't gotten the courage up to start on harness i got for my 51 pickup...
One time I put an MSD unit on an OT vehicle and thought I'd solder the BAT+ connector on for a real nice solid connection. About a year later I was going down a rough two-lane blacktop with no shoulders and BAM! Lost ignition. I scrambled around to find another connector in the tool box and crimped it back on. It's still there some 20 years later! I was just glad I found it right away and was back on the road in about 5 minutes.
I discovered non sticky Vinyl tape and love it instead of zip ties, those thing always seem to scratch me. My latest wiring project had to come in the house so I could concentrate in the warm. Started out with a Painless kit and added from there.
to get zip ties to not scratch you, either don't use them, or cut them with flush diagonal cutters, or a special zip tie tool. I'd rather not use them, especially on a car that's supposed to look like it was built a long time ago. They were space age stuff, you had to work in the electronics field to even know what they were. Non-sticky tape is wonderful.
Is electricity tough at the fifth grade level? If so were can I get a text book? Why is there so much wire in all the HAMB cars? Two head lights and two tail lights and signals take a mile of wire, really? Bob
The purpose of the generator/alternator is to move electrons from the positive post of the battery to the negative post. It doesn't "create" electrons. Another interesting point since this discussion has drifted off course is electron drift, or the rate at which electrons move based on current, conductor diameter and composition of the conductor. For instance, a current of 1 amp through a 12 gauge copper wire will cause electron drift of 0.023 centimeters per second. Slow, eh?. Converted to decimal means the electrons move 0.009055118 inches per second. Viewed from two different perspectives, electricity is both fast, and slow.
Grounds.....it's clear most of you really don't understand the function of grounds in the car. I ground the crap out of EVERYTHING, battery to bell housing closest to the starter, ten gauge ground engine to body, ten gauge ground engine to frame, ten gauge ground body to frame, and finally a ten gauge ground radiator to frame. The engine coolant carries current through the rad, ever wonder why some guys get pinholes in the rad? Others get scale buildup bad enough to clog the rad, both lessened by a good ground at the rad. Gauges don't work properly if the ground path to the engine isn't there, lights are dim or, turn signals work weird, brake light problems stump you, lastly, clean battery posts help too.
Bob do you have nightmares like this? No, Snakes on fire and the car is in the garage and I'm asleep is the recurring one. I read every HAMB electrical post and know a lot less after 10 + years. I do know that almost every post will be questioned, or corrected. It is a lot like religion, can't be seen, but it is there. I think my eight years of parochial education denied me of any hint of basic electrical knowledge, there was no Sister Mary Steinmetz. Bob
I drove my "new on the road" to me 36 to Louisville and had problems with the in-dash gauges and almost bought an under-dash SW set and install up there.I got to thinking, and installed a solid ground cable from engine to body......no more gauge problems. But.....I kept melting the fuse block where the headlights were fused (PO mickey mouse wiring stuff again) had to switch the wire to a different fuse till I ran out of fuse positions on the block and had to drive home in daylight from north Fla. I knew the wiring sucked and had bought a new Painless kit at Louisville Nats it got installed the next w/e after we got back home. Easy and no problems. Anytime I buy a "new" rod , I just figure I need to rewire after several past rides experience
I was looking around and found this. It is geared toward school kids but looks correct. https://www.howequipmentworks.com/electricity_basics/
I love wiring, (guess I was listening that day in seventh grade, Suzy must have been absent) but I really really HATE fixing wiring problems, so I'm damn careful the first time. One little tip, when soldering stuff to the end of wires, be careful not to use too much heat, female spade lugs can loose their temper and then fall off the male spade at the most inopportune times, like somewhere near Gas City Indiana at 3 AM. Guess how I know this?
Don't cut the tail off, twist it off. Works great if you're using a good quality tywrap, not as well if you're using cheapies. Grip the tail with pliers right at the catch, then twist. Twisting is the only sure-fire method I've found to leave no sharp edges; even the special tools leave some....
I thought I might put a suggestion in here that has not come up yet- buy yourself a multimeter and learn how to use it properly! Even if it's an analogue one (which, by the way, don't jump around like a digital one when you are trying to measure voltages around a running motor), find out how to read it, change ranges, etc. Measuring DC volts, DC amps and resistance will come as second nature, and will help diagnose 99% of automotive faults. Also, after you have done all your wiring, draw the circuit out, include things like which terminal on the light switch does what function, wire colours, where the swiches, etc came from (make & model of car), etc. Make a copy, leave it in the trunk. Saved me and my rusty memory many times, and makes the next owner think you were a genius!
I have wired many cars with and without kits. I normally like wiring especially when I can get in the zone slinging wire and crimping ends. I just finished the wiring job from hell. International thought it would be a good idea to use all green wire with a number printed on each end corsponding to some diagram that I didn't have. I had to follow every wire to determine what it did. I also reused the firewall plugs and repined them. Every light socket was corroded and none of the gauges worked. The gauges were the most problematic and would work on the bench but quit when installed. The pins that connected to the printed circuit board on the back would work intermittently so after much cleaning and soldering they all function. Ground, color code, and a very clean install will make your hot rod and your life better
Gm found out about skimping on grounds back in the 70's . When they had a bulletin about adding a ground wire to prevent Camaros from using the shift cable as a ground. Replaced many of them. People would have their car towed to dealership saying it worked fine when they shut it off. They started it and it would not come out of park. The shift cable would be melted.
I bought a diy kit for my shoebox when I thought I was getting close to wiring it... 4 or 5 years later the kit still sits on a shelf. What is the best way to clean paint off for grounding? Might be a dumb question, but I don't want to take a grinder to my frame etc.
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