Here's a new listing for the one I was dumb enough to buy:
https://www.ebay.com/itm/392161370859?ViewItem=&vxp=mtr&item=392161370859

After NumberDummy cleared that one up, I went over to Summit Racing and got the correct part, and some points.

Once they arrive, we'll see if that resolves things. I think he's going to clean the points today. They're new, and we're in a dry environment (Arizona), but we did get a few freak rainstorms over the last month.

 

My dad just texted me he's going to try something tonight - going directly between coil and spark plug wire. His theory is that he can eliminate/confirm the distributor cap and rotor as a problem. Thinking that the distributor's resistance can help determine. I guess, if blue when he does this, it's in the distributor. if it's still intermittent and weak, it's not the distributor?

Thoughts? Concerns?

 

I did not see where anyone said to test the coil's resistance? It's one test to find out if it's within the specified range for your particular model. That's assuming of course that it's an original coil.

As for his idea of putting the wire directly to the plug? Seems legit to me. Never tried it, but it certainly eliminates extra layers and you can then decide whether it's likely to be the coil, the wire(s), or the plug(s).
Might be extra work, but nothing wrong with the theory that I can see.

Paul

 

 

Still not much luck. He tried his jump over the distributor. He says the spark was more consistent, and a little better, but still not a full-on blue from coil straight to plug.

As an experiment, he opened up the point dwell a little, and it did help. But still not starting.

I think I'm going to order some wires just to eliminate those as a contributing factor, if I can figure out where. (at the moment, easier than making them) Other than battery cables, that's about the only thing that isn't new.

That'd be the little coil-to-distributor wire, the longer ignition switch-to-coil wire... I think... (#16 in diagram) ...any others? Not sure of part numbers.

I'm a little confused on which/where the resistance wire is on this. If there is one? Ignition switch to firewall?

 

 

I just got a new condenser today. I'm heading over to drop it off tomorrow.

Another thing I want to check - I think @1TonBasecamp alluded to it. I wanna check the coil resistance and maybe the resistor wire. I was just reading that new coils might be lower resistance, so the wire could be cutting power too low and maybe that's why the weak spark. Maybe his opening of the points improved things because it's trying to overcome the real underlying issue.

Does anyone know what the resistance should read at the coil? I'm assuming the '70 has something like the pink resistor wire in the dash somewhere?

 

For troubleshooting steps and specs it's tough to beat a good shop manual. They really break it down. Spec for V8 points coil should be about 1.4 to 1.5 ohms and 1.3 to 1.4 ohms for the resistor wire. The primary ignition circuit then, in total should measure about 3 ohms. The coil primary wire - that connects to the points, can cause trouble too, sometimes shorting to the distributor housing it passes through. And make sure the flexible uninsulated wire inside the distributor is present. It grounds the breaker plate. And the coil wire itself can be bad. I still say it's a bum condenser.

 

So sorry, this conversation's dragging on and has become something different - maybe I should change the conversation title, or start a new thread?

Here's the situation to date: We've solved the starting problem, but -- as with any good answer -- we ended up with even more questions. Yay.

Here's what happened: Yesterday, we tested every single coil and condenser we had (3-4 of them each). Not the issue. They all tested just fine with the meter. In fact every single component of the ignition system in that sense, is just fine. After I threw on (yet another) brand new condenser, I hopped in and tried starting. It sounded like it wanted to. I asked my dad about that, and he said "Yeah. That's what it was always doing. It'd try a few times, then did this the rest of the day"

"Well throw some gas in the carb and let's try again, " I suggested.

We did, and it made a noise. Not sure what happened at this point... either he bumped the distributor, or just started turning it on a whim, but he saw an improvement. So he kept twisting and I kept turning her over. The truck started. By this time, the distributor was turned enough it appeared that everything was pointing one cylinder off. But that didn't seem right.

Just to see, I went ahead and shuffled all distributor plugs one clockwise. The truck fired up. But everything looks..."off." First of all, the vacuum advance was pointing off to the driver's side corner of the fender. I'm pretty sure it should be pointing straight forward if things are dialed in correctly. When he was twisting it earlier, the vac advance was pointing as far as it could go to the left.

At that point, we stopped for the day. We went for coffee and wondered if somehow the shop that rebuilt things put the distributor in a tooth off. or maybe it didn't seat into the oil pump correctly - then dropped into place and threw stuff out of timing. But it all seemed weird, because the truck was running for a couple hundred miles of driving before it fouled on him, going home one day, and then this "can't even start it" issue began. He said the oil pump's been working right the whole time. But wait...there's more...

This morning, he texted me that he was out fiddling with the truck, and it's... "Still not right. Going over 1000 rpm, loses power to tach and fouls real bad (but doesn't stall). Disconnect the vacuum advance and it's fine. No fouling. Looks like something going on with vacuum advance. I'm thinking too much vacuum at carburetor" He's put the plugs back to where they were yesterday, and moved the distributor back to re-create the situation where the vacuum advance points forward but the truck doesn't start, unless he turns the distributor a full inch or more clockwise. EDIT: Basically, at this time, the problem is: he can start the truck and it'll drive with the vacuum advance disconnected. the plugs and timing are all good. The vacuum advance is pointing forward. The carb is rebuilt. ...but, If he attaches the vacuum advance up, the truck runs rough and doesn't accelerate. It'll run ragged and try stalling if he accelerates normally. He can overcome it by "stabbing the pedal like a race car driver" but that's no good.

Personally, I still feel like the distributor needs to be moved a tooth, and everything readjusted? I dunno. I'm stumped. I'm hoping someone has thoughts on what to check? At least it's not the electrical stuff anymore.

 

First off, do NOT start another thread on the same subject. I don't see that this one has sidled off-subject at all. It's simply a progression of possible culprits in a no-start situation.

Next, are you using a timing light in all this? Doesn't sound like it, and it's not an absolute requirement. But it sure would definitely be nice to have now that you're twisting the distributor and knocking about with different aspects of timing.

Now, a tachometer, eh? Tell your dad to disconnect it from the coil completely and try again. Old tachs can kill an ignition with an internal fault and cause all sorts of hair-pulling sessions. So for testing purposes, you need to have only two wires to the coil. The Black wire from the distributor to the negative side, and the Red w/green wire to the positive side. Nothing else, not even the radio noise suppressor if it's still there. Just the control wires. Power and ground.

And while you're doing all this, closely inspect the harmonic damper on the crank. Look for any telltales that appear to be matching notches in the inner and outer rings. When new they are perfectly aligned. If the rubber isolator deteriorates sufficiently the outer ring can spin on the inner, putting your timing marks off and giving mixed signals.
Obviously this is not a big issue if you're not using a timing light in the first place, but if you do start to use one you will need to know this.
It does not really matter to timing where your vacuum canister is pointed, or where number one plug wire is on the cap. As long as everything is aligned to the correct plug when the piston is where it's supposed to be, your engine will run. However, as you noted the location of the canister is almost always within a certain range because otherwise it can run into physical obstacles that keep you from advancing or retarding your ignition timing properly. And the number one plug wire should always be on the same point on the cap because that's what Ford set up for consistency. All the caps used to even have a #1 embossed in the cap, but I'm seen a lot of them that don't have that anymore. Not sure if yours does or not, but if it does you should continue to use it.

Re-re-verify the correct firing order for your engine. And I don't remember seeing mention of what engine we're talking about here? What is it? V8? Six? What size?

Paul

 

Ah! Apologies! I thought I had mentioned the engine. It's a 360. it was completely rebuilt just a month ago, with only a couple hundred miles on it. The rubber in the damper should be new unless we got swindled.

He's replied back that he did disconnect the tach and got the same thing. There's no other wires connected, I don't believe.

We haven't been using a timing light. We just used the "Stick a screwdriver in spark plug hole 1, and make your son crawl underneath to turn the damper pulley" method.

EDIT: To clarify, he can start the truck now. It's turned into to a "won't run right if vacuum advance is connected" issue, it seems

 

The Ford tractor (9/2/8N...) guys are having the same problems with getting good points and condensers that aren't made in China. The points have cheap rubbing blocks and cheap contacts that burn through very quickly. They recommend getting Blue Streak points/condensers with Napa being a close second.

 

Actually, yeah... we've got Blue Streak points - and the condenser's a motorcraft at the moment ( but we do have a NOS blue streak condenser as well)

But, currently the 'no-start' situation has turned into "It starts, but won't run right with vacuum advance attached".

 

Another update... I'm doing a little research. And I'm starting to think that maybe we managed to fix the starting problem and we currently just have a vacuum advance that's pushing too far. I'm not sure if the one we've got is adjustable or not. My dad's sending me a picture, it has some orange cap on the top. Even he didn't know there were adjustable vacuum advances. I might try to find one and see if we can tighten up the diaphram and finish this problem off, once and for all.