Breaker points continuity
#1
Breaker points continuity
Hello, I have an early 57 with holley loadomatic distributor. Anyways I'm having a "dizzy" of a time figuring these old systems out. (First pre-electronic ignition project ever). Has 272 yblock. My problem is no spark. I am getting continuity on both sides of point contacts when closed and open. That is a problem right? New parts so far are: coil, condenser , ballist resistor, cap, rotor, plugs, wires, points
Any help is appreciated
Any help is appreciated
#3
points
First of all the obvious, do you have voltage to the coil? The plus side should get a 10vdc supply, probably coming from the ballace reducer. The minus side goes to your distributer. You can hot wire it by sending 12vdc from your battery to the plus side to make it run, the ballace reducer reduces the voltage so your points don't fry. Anyway, hook up your coil and distributer, have your distributer cam on a flat spot so the points are closed. Use a screw driver and open the points, if they spark you're in business. If they don't probably a bad coil. If they do you have some other issue as to why it won't start.
#4
#5
#6
Continuity
Take a look at this it will explain how the pints system works.
http://www.howstuffworks.com/ignition-system4.htm
http://www.howstuffworks.com/ignition-system4.htm
#7
Points
A lot of people get rid of their points and go with an electronic module.
Pertronix makes a good one, I've used them for years with no problem, no points adjusting, no burned up points no problem. If you go with a Pertronix module you should go with a hotter coil, 45,000 volts at least.
You said continuity, the points should not have continuity when open, that is if you put a lead on one side of the points and the other on the other side of the points you should not have continuity when open. They are breaking the circuit so the coil will send it's output to the cylinder the rotor is pointing at when the points are open.
Hope that all helps, no question is ever not worth asking. Everyone has trouble with something they don't know about. That's why these forums exist! Good luck and enjoy your truck ...
-Doug
Pertronix makes a good one, I've used them for years with no problem, no points adjusting, no burned up points no problem. If you go with a Pertronix module you should go with a hotter coil, 45,000 volts at least.
You said continuity, the points should not have continuity when open, that is if you put a lead on one side of the points and the other on the other side of the points you should not have continuity when open. They are breaking the circuit so the coil will send it's output to the cylinder the rotor is pointing at when the points are open.
Hope that all helps, no question is ever not worth asking. Everyone has trouble with something they don't know about. That's why these forums exist! Good luck and enjoy your truck ...
-Doug
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#8
That's what I thought. The base of the point grounds to the distributor housing if I'm looking at it right with a braided wire. And the negative leads, condenser get juice from coil. So if I am getting continuity with points open and closed...I've got a short/grounding issue. Maybe my wire braid is rubbing against something it shouldn't? I know about electronic points but I'm stubborn about getting it running before upgrading too much
#10
It is real common for the wire from the coil to the points to get abraded where it runs under the points mounting plate. NAPA sell one that will work, you can do an Advanced Search on here for past threads about it. I'm not sure that would cause the points to show continuity, tho.
If it won't start after you or someone else did a tune-up with new points, it's also possible that an insulating washer or bushing was left off the terminal where that wire connects to the points.
If it won't start after you or someone else did a tune-up with new points, it's also possible that an insulating washer or bushing was left off the terminal where that wire connects to the points.
#11
ALBUQ... I think you are on to something. Ill have to check If an insulator is broke/worn. In my limited knowledge if my negative coil leads are possible touching distributor body...it would explain continuity all over points... Interesting, hope that's it. Would explain the grounding out.
#12
An update. I disconnected negative lead from distributor housing and I checked my test again. Now, when points are open I lose continuity! Yeah. Tested coil secondary resistance and get 8.08k and according to coil specs it should have a minimum of 9.0k so...I'm guessing my coil possibly has a short in it/not enough resistance causing all this? Well, I can replace it under warranty to find out!
#15
The points have shorted to ground, try to loosen the retaing screws as they might have been replaced with ones that are too long and are touching the advance plate beneath them, the other place for them to short is at the terminal attachment where the coil wire and condenser wire attach and pull the condenser wire off in case it has shorted out and taking the points with them.