On a 4 hour trip today my dizzy rotor decided it had lived a long enough life. In the first 30 mins of the trip the truck shuddered a bit going up hills, almost like it wasn't getting fuel, but then it cleared up. 1hr 30mins later I get a few pops out the tailpipe and the engine quits. Used my extra spark plug to figure out spark to dizzy, but none out.
Pop the rotor and see what is pictured below...luckily my wife was following me and a nearby store had a complete dizzy...

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I recently changed the rotor, cap, plugs, and wires (all motorcrft). What would have cause this?

 

Too much torque.

Looks like the rotor is burned in half, were you spooling that I6 like a V8 or something?

 

I wish I had some cool story, but I was going about 65 mph coasting down a hill lol

I typically drive like a grandpa

 

I got nothin.. that failure makes about as much sense as the flexplate failure I had last winter. You probably couldn't repeat that if you tried... luckily. Can't say I have even seen that happen before.

 

I guess I should've been keeping my extra rotor in the truck. I only bought a whole dizzy cause I wasn't sure if a haywire PIP would cause this.

 

I have seen this when the dizzy bushings get a lot of slop in them. Rotor catches stud on cap pow you are setting along side the road.

 

2X !! been there and done that!

 

It was about two years ago I pulled into my driveway and the truck let out a rocking backfire. After some investigation I found the locating tab on the dizzy had broken off and let the rotor slip. That was almost 60k miles ago and so far so good. It was odd for sure.

 

Looks like there was some serious arcing and melting going on inside the distributor. This can be caused by excessive coil wire resistance and or excessive spark plug gap, or perhaps a defective coil.

What does the old coil wire end look like? Was it burnt also?

 

It sez Motorcraft, but any chance it's not a genuine rotor but some ersatz made out of recycled milk jugs?

 

The new Napa Coil reads: primary- 1.2 ohms and secondaries 7500 ohms. I think primaries seem a tad high and the secondaries low.

No burning on the coil wire. Spark plug gap is still good- set to .044

 

Do basic or independent auto shops still have ignition analyzers or oscilliscopes? It would be real useful if somebody made a handheld (smartphone app?) that would show a trace or whatever, secondary voltage, duration, rise time in ms etc etc. High voltage does strange things when everything isn't setup right.

 

I hope not, I spent more than I would've liked for that rotor because of the name on it lol.

 

Well it does have that melty thing goin' on, that's why I asked.

 

OoO ! I was thinking you still had the old coil and wire. Those primary and secondary readings are within specs though. Too bad ya don't still have the old one.