I've been revamping my 41 over the last 3 yrs, bigger blower, bigger carbs, bigger fuel system from one end to the other, moved the alternator, switched to crossflow radiator, new rear end, lots of things in the quest for more power. Today was my big day to check for leaks, fire it up and set the timing, nothing crazy. I've got all my tools on stand by to tighten fittings, set fuel pressure, rags under all the fittings and carb bowls, fire extinguisher on stand by. Put the battery in and about 1 1/2 gallons of gas, gave everything the look over again, the one wire alternator wire was short so I had bent it out in free space with about 2 inches clearance around it, I was just firing it up to check leaks and timing. I turn the key on to cycle the electric fuel pump to get gas to the carbs, once I hear the fuel at the carbs I turn the key off and check for leaks, one carb bowl is loose and dripping. I tighten that up and cycle the key again for a couple seconds to check leaks and look the engine over, all looks good so I continue forward with cranking the engine with the coil wire off to build oil pressure. It all looks great so I go out to the passenger side of engine and put the coil wire back on, still no leaks on anything so let's light this puppy up. I get behind the wheel, pump the gas twice, hit the key and it immediately thunders to life, damn I forgot how loud and rowdy this thing is, it promptly dies after 2 seconds, huh ??? I figure it only ran off the two pump shots I gave it, maybe the idle screws are low, maybe it needs more gas in the tank, so I add another gallon of fuel, check for leaks and all is good. I'm excited, so let's fire it off again, behind the wheel, pump the gas twice and again it instantly lights off, runs about 3 seconds and dies abruptly again. I shut the key off and walk behind the truck, come around passenger rear fender and see smoke in the engine bay, scoot up there and see that alternator wire is glowing red hot, grounding on the alternator case ! I try to knock it off and immediately disconnect the power wire off the battery, damage is done, garage full of thick smoke and the wiring harness is melted down all the way back to the fuse box. I became complacent, hind sight is 20/20 and it's easy to see what I should've done with that wire after the fact. It happened fast and could've been much worse if it would've caught fire, I'm thankful it didn't. DON'T DO as I DID !
As you said " could have been much worse " I would rather fiddle around with wiring than replace Everything else. Thanks for sharing. May all your circuits be whole.
That blows! No matter how much you do, cut one corner and it comes back to bite you. Good thing it was fairly minor in damage.
Sorry it happened to you! But I’ve seen really high dollar builds that they left the rubber cover off the alternator change wire. Had a boss in a shop that would not keep the rubber caps in stock. One day he dropped a wrench and it landed on the charge wire. No rubber cover. Took out most all the same wires you lost. Funny he started keeping to cover in stock. Always something to bite us in the butt!
That makes me sick just looking at it. Glad it didn’t catch fire. What a horrible thing to have happened.
Sorry to hear this. The first start up is always something you remember! Now you will for sure! Swade not to be obtuse or bust your balls but what happened? Was the wire loose and grounded to the case? Was it not connected and just hanging and happened to ground on the case?
I appreciate your sharing the story, but I don't quite understand why that would happen. Why would that open wire touching the alternator case melt the wiring? Wiring is definitely not my strong suit so I'd really like to know exactly what was going on there that it would do that.
The other end of the wire is connected to the battery. I usually put a short length of #14 fusible link where it connects to the battery end, to prevent this type of thing from happening, but then again I've never actually tested to see what does happen if you have a fuse link in the wire. Maybe it would save my bacon, maybe not.
Glad the damage wasn't greater. Did you have a fusible link in the alternator/battery wire? You might want to also consider re-installing your spark plug wires and also rerouting them away from the exhaust manifolds. Don't forget to carry a fire extinguisher. Here's the best:
Why didn't it just melt the big alternator wire, why did a big chunk of the harness also melt? Was power trying to find every path back to ground once the battery was made into a "loop", or?
The hot cable burns the insulation off other wires near it. If they happen to be a path to ground they may also carry current to ground and burn over that length, once copper touches copper, otherwise they just get heat damage due to proximity.
Those Little Trees blue air fresheners do it every time ,,,,,I can see it in the last pic . Sorry about the problem,,,,but better now than later . Tommy
You only do that once. I put a starter on my Olds 25 years ago and didn't pay attention to how I routed the power cable. A couple of weeks later the steering column ate through the cable and melted down the column. Signals, tilt, horn, basically every plastic part and wiring. Ooh that smell, the smell of death surrounds you.
I’d say you were fortunate to catch it, like not going inside to grab a beverage, etc and think about why it wouldn’t stay running.
It was a Painless 21 circuit wiring harness with the fuse down by the starter, no problems in the past 20 yrs with it. The alternator wire ran through a separate hole in the plug wire looms, out the back and into a loom containing the wires off the starter, over the bellhousing to driver's toe board. You can see the wire is burnt to bare copper in the bundle to fuse block Then of course melted several other wires together
The only thing I can think of is the vibration of the engine made the wire contact the alternator case which is a ground, I'm not sure why it went through the harness so quickly. It was definitely glowing orange/red when I first seen it. The wire terminated into the fuse block, the wire from the starter also went back to fuse box, no telling what got crossed once it started melting through the bundle of wires.
Very sorry to hear of this especially firing up a blower motor. I have been there as well. wire fires are scary. Definitely sounds like a short, and then puff.
I'm sorry for your loss, and I surely don't envy you for having to fix it! But as the old addage goes... It could've been worse... A whole lot worse!!! You have the technology... You can rebuild it!!!
had a 6 volt battery blow up in my face...i still dont know why that happened...i reacted and turned so quickly that not even a scratch....no burns...invisible danger for sure...
That sucks, but it happens. Not too bad of a fix, just pop the connector out of the fuse box and replace the whole wire. Use heat shrink tube over the other damaged wires (if it's just the insulation), get the weather proof one with the glue on the inside. Might look hokey, but better then replacing all the wires.
Sorry you had issues. You sure seemed prepared and took all the precautions before starting the engine. Would a master fuse in the power wire from the starter prevent the catastrophic damage to the wiring harness? I used a American Auto wire harness that included a 175 amp mega fuse, if I remember correctly it was installed in the power wire that fed the fuse panel, that wire originated from the starter. I would have to look at my diagram to confirm this.
Glad you're okay...the vehicle is okay...still a shiload of work and more unplanned expense has arisen but thank you for sharing the unfortunate situation that a quick tear and wrap of electrical tape or shrink tubing could have eliminated... Am I correct that the wire to the alternator was to short and you added a length and the bare wrapped join was the catalyst?...I reread it...you didnt attach the short cable to the alternator and it bent/moved and shorted... So in this case it would best to cover the live attach point to prevent short potential...on top of anchoring it out of the way...your pics really help paint the picture...the short to the Alt is highly visible... I know all to well how much power/spark is behind a 12 volt battery having seen wires short and what is going to the plugs...
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