Hey there, I'm new to this forum and a little confused. I have some questions bout my 1970 F100 with a 302. Not sure who can even see this but any help is much welcomed. Thanks. my real question is does anybody know how to tell if dist points are bad?i did a little test and it seemed to single out the points

 

Moved to appropriate forum

 

What test are you using? What are the symptoms you are seeing?

Typically points wear out and get out of adjustment. There is no real test for them. Visually inspect the contact surfaces and reset the gap. At a minimum you need a set of feeler gauges to set the gap.

 

One thing I learned about points from my marine engine experience. When in doubt, change them.

 

But to add to what Kenny said (which is good basic advice by the way) is that in these modern days of crappy parts, just because you replace them does not mean they can't still be the problem you're trying to track down!
It's a sad thing, but those both go hand in hand. Sometimes you just have to replace something, but nowadays you gotta' at least keep suspecting the new parts until you prove that they're not the culprit.

Basically though, what was said about cleaning and re-adjusting them is 90% of the job.
There are times when points get so old and the parts so oil-soaked that they can potentially conduct electricity along their surface and fail in their duties to open and close a circuit. Had it happen on some very old points that had that old reddish fiber material as their base. Modern ones are probably plastic and probably less prone to this fault.
Just by way of pointing out it's not always just how they look and that clean and shiny points can still be bad if they're old enough. So as said, when in doubt, replace them (and the condenser) with new.

But another thing to do, and consider a good practice with these old trucks, is to not throw any of the old parts away until you're absolutely positively certain you don't need them anymore.
In the days when these trucks were still common on the road we used to keep spares of things in the glove compartment. Points, condensers, fuses and maybe even a starter relay were common sites in the box or spare parts bin.
Now that everybody is trying to keep their junk clean and tidy and parts are so cheap and easy to get, things get thrown out a lot more than they used to. Don't throw out the good stuff with the bad.

Hopefully you're receiving notifications of our replies. But welcome to FTE and hope we can help with the problem. Post up some pics of your truck when you get the chance too. We love pics!

Thanks

Paul

 

The Ford tractor guys like Bluestreak points now a days as they seem to have the best contact material and rubbing block material. When you have only 6 volts to work with, you have to have everything nice and shiny.

 

Thanks for replying, I took a wire and hooked it up to the negative side of the coil, with key on the on position and rotor cap lined up with the number one cylinder ( also had the spark plug out) anyhow I scraped the other end of the wire across the valve cover (for ground) and it made the spark plug spark

 

Look closely at the surfaces where contact is made. You can also take a fine needle file to them to clean them up if they're not too corroded.

 

Ok, i may take them off and do that but the thing that gets me is there some what new like the guy I got it from 4 months ago put them on. Also it was running ok ish like three weeks ago but now it won't spark!😫 I do have a set of new point I got, should I put them on and try it?
Thanks

 

The points themselves are probably ok then, but you could try another condenser/capacitor/thingy and see if that helps.
Also, the same looking capacitors are found as noise suppressors on the positive side of the coil. If one of those goes bad it can stop the coil from sparking under normal conditions.
Sounds likely that yours is fine though, considering you're getting a spark.

Next thing I would do is turn the engine over while you're watching the points to see if they're opening and closing like they should. You can watch them, you can test them with an ohm-meter, you can test that theory with a dwell meter. But they need to fully close and fully open in order to make the coil spark. Just like you did when grounding the negative side of the coil.
Spinning the engine will also tell you if the distributor is even turning. Sometimes the roll-pin holding the gear can shear off. Sometimes the gear teeth get worn down. Sometimes a timing chain can break (very rare, but not impossible) and other things happen as well.

Since you know you have spark when manually triggered, are you sure you have fuel? Can you see gas squirting out of the accelerator pump nozzles when you push the throttle down by hand? Can you smell gas?
Do you have a regular and consistent supply of voltage to the positive side of the coil when the key is in the ON position? Does wiggling the wires make it flicker? Whether using a test light or a meter, this stuff can be tested pretty quickly and easily.

Paul

 

My last "new" condenser burnt up in 100 miles. Junk.
Yours could be grounded out. Unhook it and retest for spark again.

 

Thank y'all for the answers, that helps a lot. So it sound like I should get a new condenser or I should just unhook mine? It does have fuel getting in and out of the carb,the rotory button does move... but another culprit could be the dist is out of time... I know my battery is probably not in great condition (due to dying multiple times) but it was good enough to set a spark by bypassing the points, there's probably lots of little things wrong with the electrical system but like I said it was running a few weeks ago.

im aboutin to set it all up to do that "test" again but I'm gonna pull the negative wire of the coil and kinda wiggle it on the stud and see if it makes the plug spark. If it doesn't than I know it probably a ground of some sort in the distributor.

Marley

 

I may be of base here, and I'm sure some of the other guys will chime in and correct me if am wrong.

I believe there's a resistor wire to the coil and when you're in the start position I think that wire bypassed you might check to see if you have power to the coil in the start position as well as the run position.

 

Can't unhook the condenser inside the distributor. Won't work well that way. (edit: except as a test for a bad condenser of course!)
The external ones on the voltage regulator and the ignition coil however should be disconnected for testing any time either one of those things does not work. When you lose spark I recommend disconnecting any tachometers or noise suppressors from the coil just to see if they're part of the problem.
But the one inside the distributor has to stay, or get replaced, or tested (if that's possible?) or swapped out temporarily for another to see if that helps.

The other thing to disconnect when diagnosing ignition woes (and I don't remember if we already talked about it) is the Brown wire from the starter relay's "I" post.
More on that below.

Just like you did with your ground test to the coil though, you can test that same function using the points.
With the spark plug and wire lying near the engine like before, and the points in the closed position, turn the key ON and with a tool of some kind (like a wood or plastic implement) like a popsickle stick, carefully pry the points open and then let them close. Each time you open them up the sparks should fly at the plug end. You will also likely see very small sparks at the points too. If you see big sparks, then maybe the condenser is not working? Not sure how consistent that would be, but it might be a clue worth checking on.
And at the same time you can check voltage at the coil positive. Could easily be battery voltage when you first turn on the key, but it should come down to somewhere between 6v and 9v after a short time.

And as always, whether with points or electronic, don't leave the key ON for very long. Just long enough to do some quick tests then turn it off. Too long with current flowing through things will heat them up. Coils get hot, points burn, condensers wear out. But a couple of minutes at a time is not detrimental.
Easy to forget though!

Ok, good. Both good signs.

Yes, it could be out of time. Anyone with an old vehicle should own a timing light for just these (all too frequent) occasions.
If you don't have one, maybe your local auto store's loaner program includes one of those?

If the engine is still cranking normally, there is enough voltage to fire the ignition.
If it's cranking slowly, then it might still spark, but nothing has enough vigor to start. While it's cranking even close to normal though, you should have good sparkage as long as the wiring (like Tim was saying) is still working as expected.

The distributor getting a good ground connection through the case to the engine is important. It's less critical with points than with electronic, but still important. So again, a timing light is critical because you may need to take the distributor out to check and clean it.
Where it enters the block it can be oily and perhaps even have burned on oil. Can also be rusty in the bore because the block is cast-iron. And because of that, you can even get serious corrosion of the aluminum because of dissimilar metals reacting. The oil helps in this regard, but it's a balancing act.
If you have a timing light you can pull the whole distributor out and wipe it clean, check the bore for rust, then put it back in. The clamp should be clean too since it's also part of the ground connection.

Regarding the main ground though, if the starter can crank then the engine is well grounded. The slower the cranking (assuming good battery) the more you should check your cables and other stuff that can put a load on the electrical system. Every amp that has to go towards the starter and other stuff, is one less that can power the ignition.

Correct. The Red w/green wire coming out of the ignition switch and visible at the engine for the coil's positive side is a resistor wire under the dash. Usually some shade of brownish/pinkish/uglyish under the dash, Ford used a resistor wire instead of a common ballast-resistor we see on some vehicles with the white ceramic base bolted to a firewall or wherever.
These can go bad and not get enough voltage to the coil. Hence the need to check voltages at the coil's positive terminal with the key ON. Should be 12v initially, but go down to between 6v and 9v when running. When testing a person should always know what the battery voltage is so they can compare to what's at the coil.
If you see less then 6v you might do some deeper testing. If you see less than 5v it might be seriously weakening your spark production.

The Brown "I" wire at the starter relay plays two roles.
It adds full current and voltage to the coil during START only, to help with quicker starts especially when the Red w/green wire is already heated up and voltage at the coil is low. And it also helps when your ignition switch is old and wearing out and might not provide power to the coil during START like it's designed to.
In that case the engine would not fire until you release the key to RUN. But with the Brown wire working in START only, you can still start the engine.

But because it's connected to the ignition wire, and starter relays are known failure points in today's world, a good thing to do while testing for ignition problems is to disconnect the Brown wire from the starter relay/solenoid to see if that changes anything.
If disconnecting the wire gets things working, then the starter relay is bad and shorting out somehow.

Always good to look from every angle!

Paul

 

The engine will not run well with no condenser, but it will run. I had to drive my truck 15 miles home one day with no condenser(it had shorted out). You do just about anything to save from paying to tow it home(with a boat on the hitch). That was 30 yrs ago.

Few years back, when the condenser failed, I again unhooked it to see if car would start. It did, proving what was wrong.
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