The beauty before she burned up....


The beast after she burned up....


Hot Spot

Hey y'all I have a 1970 F-100 Ranger XLT with the 390 motor in it. She caught fire the other day while the wife was at a stop light. She wasn't injured and she was able to save the groceries out of the cab!


It looks like it was electrical and most of the wiring in the engine compartment is singed or destroyed. Fortunately, the radiator hose blew up too and put the fire out before the Fire Department even got there so it really saved the truck all together.


What I'm looking for, and would like to know is what is my best option to get her back on the road. I haven't had too much time to fool around with it since it's about Easter (today is now....) but it looks like I would be able to splice back at the fire wall (no pun intended) and run new Starting, Engine and Lighting Circuits from there.


Anyone ever have this happen? What course of action did you take?

 

Hmm I'll tell you how an why it caught fire.
The Msd blaster ll coil is not suppose to be mounted "horizontal" , The oil filled coils over heat and boils the oil an pushes the top end cap out. Hot oil sprays out catches fire.

This is noted warning not to mount the coil this way, says mount coil "vertical"
Even on Summits web site has this listed.

It always pays off to read & follow the instructions

 

Ouch. Welcome in. Sorry about the circumstances.
The guys will weigh in one-by-one. I will start by pointing out what looks like a heavy red cable that is grounded to the fender apron in the upper left of the first photo.
If that is the battery ground, that is a no-no and may be the source of your problem. The battery ground should be to the engine block and the engine should be grounded to the cab by a strap. Start there.
I don't think that you have a terminal disaster. It can be resurrected by replacing the obvious burnt parts, methinks. And by chasing the current paths around the alternator.

 

Reasons #1 why my main power to the cab now has a fuse.

 

What size fuse do you use and where do you put it?

 

Thanks for the information on that coil. I had no idea. The truck came with it mounted as shown in the first pics. (We've only owned it for 2 weeks and only drove it short distances.) When I replace the coil, wires, cap and rotor I'll mount that puppy the correct way. Thanks again for the info.

 

It seemed to me that it is repairable too! and my wife was excited too (really) that we would probably be able to get the old girl back on the road! The item in the picture you're referencing is a stub of pipe someone else put in there to hold the Heater lines up out of the way of the exhaust.


Tell me more about the current paths "around" the alternator. I'm not sure about that and I want to be sure that I'm understanding the "why" and "what" of it.

 

yes, where did you put it?

 

60amp maxi fuse, mounted right where the main cab power comes off the solenoid. I cut the main wire, put a 3/8" female spade terminal on each side, and plugged the fuse in. I would prefer to have it in a holder, and will most likely replace this with an 80amp manual reset circuit breaker when I rewire the truck, but the wiring was so hacked I needed to do something.

 

So, I finally had a few hours to survey the actual damage and was actually pleasantly surprised to find that it looked a WHOLE lot worse than it was.
I found the coil, cap, plug wires all toasted. Obviously both wires for the Coil were nothing but ashes. I found the wire for the distributor toasted (16 on the diagram), the Water Temperature Sender (39 on the diagram or Oil Pressure Switch 31 on the diagram) Whichever it is it is directly behind the distributor.....I wasn't able to salvage the "push-on" connector, so I'm not sure how to correct that. I'll see if there's an aftermarket one on Amazon.....or check my nuts (he said nuts......LOL.) bin and see if I have one that tiny and use a ring connector.
A quick run to Autozone to grab all of the parts and changed everything out one piece at a time. I found the Alternator wire fried from the Alternator up to the Summit carb and also the ground on the carb was charred, so I swapped it out too.


The interior of the Distributor was in pretty good shape thankfully, so I'll just clean that up good and reassemble. Should I (probably will just because....) clean the points while I'm in there....?


Tomorrow I'll do the fuel lines which were pretty charred as well. new in-line fuel filter since the one on there cracked (not busted/broken, but cracked the glass). New top radiator hose and she should be ready to fire up.


I did look over several pics of the original coil location and since I bought the OEM part will mount it in its proper place and position.


Any precautions that I should do/make prior to attempting to fire her back up? Looking for sage wisdom right here.


I am so appreciative of the help y'all have offered on this. I want to keep this truck around long enough to restore with my son and it means a ton to me that y'all have chipped in on my sons first ride! (cry.....sob.....etc. Now back to manning up!)


Oh, wait I just heard my wife yelling for me! Gotta run! LOL


Thanks guys!

 

Sorry to hear about the truck.
You were lucky it put it's self out or you may not be able to "rebuild it".
Was 1 of the first things you bought a fire extinguisher to keep in the truck?
Reminds me I should get some for my garage.
Dave ----

 

Sorry to hear about the incident. My worst nightmare is your reality. Don't put the clear glass filter back on there. They suck. Yes clean the points and re-gap, or just replace them. If you replace them, buy Motorcraft points and condensor ONLY (and actually, that goes for all of the ignition components). If you re-use, I have used a doubled over piece of extra fine sandpaper to clean the face of the points contacts. Like 4000-6000 grit.


PS, you should be able to use nuts and washers on the sending units instead of the push-on connectors....Nuts LOL
KOT390

 

No biggy, it's not as bad as it looks. I had a 428 in a 69 highboy burn about the same once, had it up and running in half a day easy. If you use a factory coil, Ford layed them down originally, shouldn't be an issue unless the new coil you choose says different. It might be a good time to switch to a Duraspark electronic ignition.
I like to do them with an EFI coil and GM 4 pin module. Simple

 

Tread, did you find the root cause of the fire? Is Orich correct about the coil oil?

 

Ouch, sorry to see this. Going by the picture:



You can see the fire "burn" area is right at the front of the coil. The lid of the coil is blown off. That suggests to me that the improper mounting of it caused the fire.

The good thing about these trucks is the fact there are only about 3 wires on the motor coming from the harness at the firewall. 12v to the coil, water temp, and oil pressure.