I don't know that I'd waste the time re-wiring a car that was so rusty I didn't believe the chassis sound enough to be a conductor My Baja body is a rotted POS by my standards and it works just fine.
I've never had a problem with the braided straps, if they're bad they're easily replaced...We run two on the transaxle-to-framehorns in Dad's car - Which is another thing to keep in mind when wiring. The current of the starter motor is 'mechanically' grounded by means of the transaxle case and one of these straps from the factory leading to the framehorn - if/when they fail with vibration over the years the starter will seek a ground by an means possible...So (given the trans has rubber mounts) the throttle cable and clutch cable become the only conductors (they're actually 'always' being used as conductors in some sense) and will burn-up from excessive current...
In the event the commonly missing 'extra ground' German engineers thought it necessary to run to the housing of the generator/alternator is still attached, and the braided strap suffers, it'll be likely to catch fire.
…which is why I go to the starter bolt first then to the chassis.
Not trying to start an argument but those are some things that I mentioned, after 50+ years with cars I have run into numerous times. You never really know what is under paint, Bondo and carpeting (especially numerous layer of carpeting and padding)... which can cover a multitude of sins. Over the years I have run into some of the biggest hash artists in the PNW.
In electrical we always say no two guys will install alike...It's just good to understand the logic and advantages/disadvantages. You're just saying that you run an additional large ground wire from the bottom starter nut on the transaxle to the framehorn?
The Baja has such a bad body, I ground the tail lights to the extra M6 tin screws on the engine (no rear tin), And both Dad's car and the Baja have ran LED lighting w/o issue - LED's can be funny about their grounds.
"... In electrical we always say no two guys will install alike..." How true, how true!
With my glass buggy I have solid mounts so no need to need to run the second ground but when I do it… yes, I would replace the woven strap with a regular battery cable of more than sufficient size/gauge (people have a tendency to run under size battery cables).
The woven/braded straps are made up of many small strands which give a lot of travel surface and flexibility but also corrode down quickly. Because of the flexibility they have a tendency to worry/fray themselves and the strands can fracture at the solid connections at the ends with metal fatigue which degrades their working at full capacity (as when they are new).
In the old days, when there were auto makers that use positive grounds for their cars, woven straps were pretty common and them failing was not uncommon; as I remember, GM used a lot of them on the under (wooden) mounted batteries. Even with neg. ground cars, those straps have a rep of short life... and that is when you had 6v cars which had more amps running through their wires. I don’t think that the manufactures do as good of a job making the braided straps as they used to as their short life seems to be even shorter now days.
When we put v8 engines into 6v cars we used the 12 v to spin the engine but took a 8v/9v tap off the battery back when they had exposed lugs) to run the rest of the electrical systems. You still have a short life (the head lights sure are bright) to things but not as short as with 12v; only a few of the gauges had to have dropping resisters in them to work.
Remember, this is my opinion and it only deals with wiring from scratch.
Speaking of under-size cables...Mario at 'The Dub Shop' actually hooked me up with several of the custom over-size cables found in Dad's car - and they've worked great.
Wiring isn't just a problem for aircooled's...I re-wired Dad's friend's `92 Golf headlights with relays and he was shocked at how much light the same lamps could provide with adequate voltage.
One of my old racing partners was into Fiats (and I confess to myself once owning an X 1/9, which was actually a pretty awesome little car but nobody here cares to hear about that). Point is, Fiat engineers felt obligated to provide a small braided cable from chassis to alternator housing as an adjunct to the main ground strap which bypassed the engine/transmission mount...I guess they thought it was necessary for more precise voltage control by the regulator...but that's giving them the benefit of the doubt, it could just be that they did that particular bit of "engineering" after a lunch break where too much vino was consumed. Because they wrapped that little ground cable up nice and tightly into the main chassis-to-engine harness, it was ready and willing to try to handle the starter motor draw in the event that the main ground strap connections failed - thereby frying the whole harness. This is an annoyingly frequent problem with Fiats, (often it's the only thing taking an otherwise perfectly-good car off the road) and it just goes to show how a little forethought, thinking through the worst-case scenario before wiring your car, can save a whole lot of grief. VW waterpumpers suffered a similar problem because of their 3-point battery ground cable (battery to eng/trans with an extra lug midway to ground the body). If the body ground failed, the next time the key was turned to "start" the entire starter current tried to pass through such nebulous paths as the oil pressure warning light wire, with predictably disastrous results.
IMO tidy, car-show-ready wiring that has every harness tightly wrapped up in order to look as neat as possible is dumb. Shorts can and eventually will happen, no matter how well you design the system. Leave a little "breathing room" around each conductor so that in the worst case, should it go crispy, its neighbors will be minimally affected.
I thought I was all set to order an OEM harness, but I was wondering if a Wiring Works OEM harness have all that extra wire (that I don't need) for the voltage regulator under the seat and the diagnostic plug in the engine compartment? I spent another hour or so searching and reading STF and Samba threads on wiring and came across some other highly recommended harnesses, Ron Francis and Rebel Wire. Any thoughts on those? The Rebel seems like a cinch to install, even amongst those with little electrical knowledge.
I didn't see any mention of a VW harness on Ron Francis' site, but from what I've read, you can call him up, tell him what you need, and he custom makes one.
Ah...FIAT (Fix It Again Tony - A bacronym or backronym is a phrase specially constructed so that an acronym fits an existing word.). My ex-brother-in-law had a couple of them; they had a two year warrantee and the day after his warrantee was up on the first one the X 1/9 burned to the ground in his driveway; electrical problems. His got another one but passed it on to someone else just before the two year warrantee was up. Other than that they were nice cars.
There are a lot of manufactures of cars both in the US and abroad that have traditional wiring problems and not of them were making refrigerators in England (there used to be a T-shirt you could buy that said: "The British drink warm beer because Lucus (aka the Prince of Darkness) makes refrigerators" http://www.bobistheoilguy.com/forums/ub ... er=2367686) and never seem to fix their traditional problems.
Lee
Last edited by Ol'fogasaurus on Wed Dec 12, 2012 8:39 pm, edited 1 time in total.
As for the VW "diagnostic" wires of the `70s, not a single one is needed for the car to function, and none will ever be missed. Perhaps one could come up with some useful purpose for the flywheel-triggered TDC sensor, but beyond that IMO it's all just a waste of copper.
You could take the extra B+ wire off the firewall port and run it to an internally regulated alternator in parallel as I did on Dad's old `77 that had high-resistance through the factory B+ wire that went through the C-pillar - just adding another wire in parallel significantly increased the voltage to the battery - and the car. And there's no shame in having extra wires in the loom for future expansion should you decide to use any others and 're-assign' them.
Matter of fact I deleted the B+ that went into the loom that runs through the C-pillar entirely - Mario made me a HD cable to run from the alternator to the back of the starter motor...and I ran the front B+ or '30' wire along the passenger floorboard, and through the front firewall instead of running them with the wires in the main loom along the stock route...But the setup in the `77 was much simpler for great gains.
Touché, if you're clever (I'd like to stop right now and take a tiny bit of credit for the fact that Chris IS) you may find a useful repurpose for the "diagnostic" wiring. For example, they're an easy way to breach the engine compartment firewall for an added gauge wire...my point, however, was that when rewiring an entire car the diagnostic-plug wires are superfluous and will not be missed if omitted, so there's no need to spend more for a harness which retains them.
I had a wonky ground on a 76 Rabbit blow the spring in my speedometer once.
As in "fuse".
Addendum to Newtons first law:
zero vehicles on jackstands, square gets a fresh 090 and 1911, cabby gets a blower.
EZ3.6 Vanagon after that.(mounted, needs everything finished) then Creamsicle.
If you have a single 14 AWG wire running a device 12' away (and ground it at the device) the appropriate fuse would be a 10A...But consider if you'd like to run five 10A circuits the same distance - bundled w/grounds leading back to the bus-way, you'll need to run 10AWG - or 12AWG if grounding at the device (assuming steel chassis w/o excessive cutting/welding/rust/paint to the point it should be tossed anyway).
My Baja body is a rotted POS by my standards and it works just fine.
