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Just trying to hunt down why I'm not getting spark.
On the coil, Positive has two wires going to it, one from the ballast resistor and one from the battery. Which makes no since to me, why put a resistor on one wire and give it full power from the other wire to the same post. How does the coil know which wire to pull power from? Unless there is a switch between the battery and coil that I didn't see that stops the power from the batter once it reaches temp or something? Anyway, the negative terminal goes to the distributor. and the high power wire in the center goes to the distributor cap?
Is that all correct?
Between the two terminals on the coil, I'm getting 1.8 ohms and between either terminal and the center high power plug, I'm getting 6,990 ohms. I feel like that 6,990 ohms should be higher. I have another coil I pulled from an old FE engine and has been sitting in my garage and I tested it to compare numbers. I get 1.8 ohms and 9,980 ohms so about 3000 more ohms on that coil. could this be my issue?
There is a resistor divider network on the coil. That sounds more complicated than it is. There are two small posts on the starter solenoid relay. That's where the ballast and straight voltage switch. When the key is turned to START, the ballast resistor wire is bypassed and straight battery voltage is fed to the coil for a hotter spark to aid in engine starting. When the key is released to RUN the resistor wire feeds the coil. The voltage is reduced is to keep the current (amperes) low through the primary circuit, to keep contact points from burning up.
Coils come in different configurations. The primary resistance of 1.8 ohms sounds about right, but the secondary, who knows? Depends on the application. Some coils were used for electronic ignition. Some were not. The stock points coil had (about) 1.4 ohms resistance and the ballast wire added another (about) 1.4 ohms. SO, about 3.0 ohms total is in the ballpark.
Ignition coils are very often replaced unnecessarily. On the other hand they can have just a few turns shorted out in the secondary winding, and it would be about impossible to tell because the resistance would measure OK or in the ballpark. They also can intermittently short out when they get hot. This is hard to find without a scope.
If you're running a points distributor there are a few things that will cause "gotchas". A Shop Manual is very useful here for troubleshooting because they are written in a logical straightforward way to test that will use a process of elimination to zero in on the problem. Points need to be "dressed" now and then with a point file and will get a layer of skunge on them very quickly. Check for continuity between the moveable point arm and ground in the distributor. The condenser is also critical part, if it is open it will run very poorly if at all, or backfire and intermittent. Good grounds are important. The breaker plate has a copper ground wire to the distributor housing. The distributor housing bonds to the block. It used to be routine to replace points and condensers as part of a tuneup but replacement parts available today are such poor quality this is probably a bad idea.
Tedster9, thank you for that write up. It really explains the ballast resistor power thing I couldn't get my head around. Thing is, the coil is getting 12v when the key is turned to the on position. Not just the Start position. This seems like a separate issue though. I doubt getting 12v would keep me from getting spark. It would just make the spark hotter. Right?
I guess my next step will be to pull the cap and spin the motor, to see if I get spark at the points. And then try to figure out how to test a condenser (bet there's a few YouTube videos on it) After that, I'm not sure but I'll probably replace the coil, simply because I have one that I know is good and I have already taken the old one off to test it. Just to rule it out , but I suspect you're right and it isn't the coil.
BUT I really want to put a pertronix in it, so maybe i'll just do that. Just think I should figure this out before I spend the money.
That's not a bad plan. Dig around the intertubes and find a troubleshooting manual or tune-up guide for points ignition. There's all kinds of tips and tricks with test lights and voltmeters, "If this, then check that, if A is X, then problem is Z". If the spark at the plugs for example is missing or weak, then the first quick test is to pull the coil wire from the distributor cap and hold it about 3/16" from a cylinder head bolt and see if the spark is good. If the spark is good, then the trouble lays in the distributor cap, rotor, wires, or plugs. Figure out what the problem ain't, is just as important sometimes.
Quick question, I haven't found the answer yet, but i'll keep looking. Should the negative side of the coil read 12v with key in on position? Im guessing yes since I get continuity from the two posts on the coil. But 12v on a terminal marked "negative" is messing with my head.
Took the cap off, and spun the engine. The points weren't sparking at all. Went to pick up a set of points & condenser but they had the correct pertronix in stock and it was only about $35 dollars more. I'll try installing that tomorrow and see if that gives me spark.
Yeah, the ignitor was 85 but my local parts store wanted almost 50 for the points and condenser..
But I just F'ed up my distributor anyway. Looks like i'll have to buy a new one.
I pulled the points and condenser off and decided I should clean under the advance plate. But it wouldn't come up because of that nut, (I'm sure you can see where this is going) hmm, a 3/4 is to big and an 11/16 is to small (that should have been by first clue) but an 18mm fit perfect. Why would Ford use metric? Gave it a half a turn and the damn thing just popped off. No threads. That's when I realized that the magnet from the pertronix kit slides over that "nut" I'm guessing I could press it back into onto the shaft but I'm guessing it's position is pretty important.
Anyone know if the dizzy from the same year yblock would be the same with a different cap?
You sheared off the distributor cam with a wrench?? I'm not picturing what happened. You ate yer Wheaties this morning, I can tell! Which distributor do you have?
It may be you could get by with a new clip that secures the reluctor assembly. I think.
I barely put any pressure on the thing. I use to own a vintage motorcycle shop. Those old motorcycle engines are 90% aluminium. I got real good at, "don't force anything". I put a short box wrench on it and gave a small push with my palm. Less than 10 lbs of pressure. Hell, probably less than 5 lbs, really. Thing just popped off.
if it was that loose, it was probably bad to begin with and possibly had something to do with why I wasn't getting spark.
Anyway, I found a remanufactured one on Rock Auto for $80. Didn't want to spend another $80 but didn't seem I had much of a choice.
Anyway, I found a remanufactured one on Rock Auto for $80. Didn't want to spend another $80 but didn't seem I had much of a choice.
You have a Y Block? Cores are tough to find. What the rebuilders were doing the last few years, is using a Ford SB distributor. These are not the right length. Don't buy a distributor from anybody unless you know for a fact it is correct. No offense to RockAuto but the odds they are selling a Y Block distributor are not good.
Show a picture of your distributor. You know the reluctor is secured on the shaft by a small circlip right?
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