1976 F100 360 4WD Manual

Hello. I've been reviewing threads on here like mad in an effort to locate something similar and see if this has already been solved but I'm not seeing anything conclusive. I think I have a few issues that are stacking up upon each other and affecting each other.

I am experiencing a wonky spark issue.

I pulled plug #1 and verified that I do have spark right now but it only fires once every 3-4 seconds. It is pretty regular. It goes:

SPARK(one mississippi-two mississippi-threemississipi-four missi)SPARK(one mississippi-two mississippi-threemississipi-four missi)SPARK

Considerations: I recently replaced the harmonic balancer, dizz cap, rotor, and starter.

When I replaced the balancer I needed my brother to manually lock the flywheel. We got it on there and I verified that I had spark. Since it wasn't firing I thought the timing was way off (it was barely running and was mighty rough.

It sat for a week or so, stupidly with the air filter off and carb exposed. When I went out to reset the timing and put a socket on the balancer bolt to turn the crank it was not turning by hand. Not sure why, I'd never had a problem with it before. I ended up getting the balancer to TDC by just hitting the starter to crank the balancer around until it lined up. I reset the timing but had no spark and had to leave it for a few days.

This weekend I was out on it again. When I hit the ignition nothing moved, almost like it was seized. I went and got a new starter (the old one was having known issues). When I started it with the new starter I could see the fan move a few inches before stopping. I then put a surge box on the battery and after a couple tries with the fan barely moving I got it to turn all the way over, and then on the third or fourth try- boom! it just started turning again. I got out, threw a socket on it and manually rolled the balancer to TDC, pulled the dizz, reset it to position #1, and recapped the dizz. Hit the ignition and it would turn over but no fire. That's when I pulled plug #1 and saw the intermittent spark.

I am seeing lots of ignition module and coil pick-up solutions but I am leaning towards the timing set. Could the intermittent spark be due to stripped timing gears?

When I get home tonight I'll pop the dizz cap and turn it over to makle sure the rotor is turning (just learned that trick reading a thread today).

I'd love to hear similar stories and solutions or just suggestions. I have little time and less money these days so I'm gathering research in hope to work smarter and not harder in the coming week.

 

i have a couple ideas based on your story:


-----When I replaced the balancer I needed my brother to manually lock the flywheel.------

When you did this was it TDC on #1 compression stroke and not on another?

Is it a points setup or duraspark? If points, check the points and condensor

If need be, you can mark the position of the rotor on the dizzy and pull it and check the dizzy gear. Any damage to it would be a good indicator of stripped/worn timing gears(to do a quick check, not a definite answer).

 

Honestly, I don't know where the TDC was located when I put the new balancer on. Without thinking a whole lot about it I just popped off the old one and put on the new. Didn't think it could go on wrong.

It's a duraspark set-up.

Reading your response reminded me that it was reaaalll sticky getting the dizz back in this weekend. Like, weirdly so. In the past it would more or less slide right in but I had to finess it a bunch yesterday. That got me thinking that maybe there is some dizz gear damage.

UPDATE: I just went out, popped the dizz cap off, and had the wife turn it over. Wasn't too surprised to see the rotor just sitting there calm as can be.

Any recommended timing sets?

 

Before you tear into the motor to replace the timing chain, make sure that the roll pin in the distributor isn't sheared. That's one explanation for the rotor not turning; the other is the timing chain.

 

Good call fmc.

I took a gander at the dizz and the roll pin is in nice and secure. spin the gear by hand the rotor goes round and round.

Nice to have that possibility eliminated at least!