Electrical fire... secondary ign - why? (long)

Well, I went out to run the valves and torque the heads on my recently-assembled 383... and found my little truck had been playing "car-b-que".

I went and snapped some pics w/ my daughter's camera, but she's got the cable; won't be able to post pics until the weekend.

Let me give a rundown of what had happened on the last trip home a couple days ago, and what I saw today - see if anybody can do the forensics on this. I'd like to get the cause figured out so I don't have it happen again!

I went over to a friend's house, about a fifteen minute drive. The cooling fan switch (brand new part ) had failed, but there were only three stop signs; shouldn't heat up too bad - get to keep moving. Got there w/o incident. Had the hood sides up showing off the new motor.

No signs of anything hot (other than the weather; it was about 95 out).

Took the old girl home; seemed like no problem. When I passed a car pulling into the driveway, I thought I smelled something hot, but just for a moment.

Today, I found that the coil wire (wire set had about 1 week run time on last motor in the truck, five years ago), all four pass side wires, the distributor cap, and the cap end of all four drivers side wires were burnt. To a crisp. The insulation turned to powder in my hands. There's a hole the size of a pencil eraser burned thru the cap.

The wire boot on the coil tower appears to have turned to very hard plastic and fused to it. The coil WAS an MSD Blaster 2. Stock ign. module and ballast.

There was soot all over the hood and across the firewall.

The heater hoses which ran over the pass side valve cover were burnt in half. One of 'em is missing about a foot of hose.

The two small wires going to the alternator fields have some heat damage to the insulation, but only where the plug wires were close. Not at the terminals where they plug into the alternator.

The old girl was running about 195-200 coolant temps, but it was in the mid 90s out; I figured that wasn't too bad. There was no steam or smoke coming out of the truck when I shut it off. And it didn't miss a beat; didn't misfire, buck, etc. Ran like a champ.

I thought I might have had a fuel leak (my pressure regulator is on the side of the tunnel ram, right over the pass side where everything burned), but I couldn't find any signs of leakage when I washed the area off.

Anyone have ideas about the cause? I've seen the ends of a wire burn up from a bad connection - not half the d**n set. Did the MSD just get too zippy for the secondary ignition? Do I just need to put it back together with some hickory chips and a pork shoulder?

Hoping someone can shed some light on this; I'm pretty lucky I didn't lose the whole pickup!

Thanks,

Bill

ya, my guess is you had a fuel leak and it went WHOOOSH from the engine heat.

youre lucky it went it out

Fuel leak and fire.

I'd thought it was fuel lines, too. But had to rule it out after inspection.

All hard line there; no signs of leakage.

No signs of fire on fuel lines. If they'd been spraying on something six inches away that lit off, the lines would almost undoubtedly go up too.

And they were holding pressure when I cracked 'em to get at something behind the regulator today.

But, pretty sure this wasn't a fuel leak.

And it probably wasn't a wire laying on the header; the front two on the pass side went under the headers; the rear two went over the valve cover and between the tubes. And they didn't flop around a bunch or anything.

I'm wondering if it could have been foul play?

Don't want to be paranoid, but... I just don't see how this makes sense.

BTTT for more guesses.

-Bill

Awhile back a guy (on here) posted pics of his burnt rotor which iirc the rotor blade got bent from putting the cap on at an angle & the large gap made for some serious arcing but nothing close to the damage you have experienced (& it was all contained under the cap). I would not suspect foul play.

Yeah, I wouldn't want to think of someone burning poor Lulubelle. And probably not likely.

Looking under the cap, the terminals were colored blue-ish. But there was no bad pitting; nothing like you'd see if it was hot enough to start something on fire.

I think the rotor was phased pretty well; the little marks I could find on the terminals were in the middle.

I'd wondered if the coil wire started it, and then caught other wires.

I've seen the terminals burn off the ends of the wire if there was a problem, but never just flat go up in smoke.

I've put in a PM to SunroofGTX; first, I need a wire set (duh), and second, maybe he's run across something like this before.

-Bill

there is no way an ignition system could melt down like that without fire. a spark plug wire is so heavily insulated that it nwould take a HECK of a lot of power to melt like that. the ignition feed would melt and dissolve WAY before the spark plug wires melted. the fuseable link would be gone and the car would stop.

you leaked fuel. check your carb. probably spit gas out the fuel vent. Holleys?

Quote:

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there is no way an ignition system could melt down like that without fire. a spark plug wire is so heavily insulated that it nwould take a HECK of a lot of power to melt like that. the ignition feed would melt and dissolve WAY before the spark plug wires melted. the fuseable link would be gone and the car would stop.

you leaked fuel. check your carb. probably spit gas out the fuel vent. Holleys?

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1. The Coil produces "Voltage" not Current. Current is what would melt it.

2. If it was the secondary Ignition why only 4 Wires (On the same side) and the coil wire, why not the other four wires?

3. Carbon Tracked Wires (Spark plug Wires) will blow a hole vice melt down.


something on that side of the engine had to be "Flaming" to cause this. Maybe something blew on the manifold and caught.

Not the Secondary