How much resistance should I read across the terminals? Can I even tell if it is bad? I read no resistance........
A typical 12 volt coil should have a primary resistance of 1.25 ohms give or take a little. Make sure the ohm meter is on the low scale. The secondary resistance ( taken from center tower to either terminal) should be ( high scale) from 5 to 8,000 ohms ( again give or take a few thousand). Although the actual product spec is critical , being slightly out of range wont make the car not start etc. However parts life is determined on the proper condition of each dropping resistance in the working ignition system. More than glad to help.
across the primary terminals very low resistance, say 1.5 to 9 or so ohms, from primary to secondary high resistance approx 1.5k to 2k ohms Larry
Here's the deal I am troubleshooting for a buddy over the phone. He has a 56 Chevy with a 235. The whole car was in boxes when he got it. EVERYTHING. The wiring, the motor etc..... He is at the point where it should start but it won't fire. Has 12V to the coil, it drops back under starting conditions but no fire to the dist. We just don't wanna start throwing parts at it .
voltage will drop when cranking, ask him to put a test light on the neg side of coil and see if it flashes when cranking the engine over Larry
The ballast resistor is working right it drops back to about 9.6V. I'll tell him about the pulsing light.
Also, there is a small condensor on the outside of the case of the distributor. Is this for radio noise suppression? If so what is it supposed to hook to?
check the points, (I only say the next one because twice in the last month have cars come in missing one...) is the rotor in the cap? and if he pulls the coil wire off the DISTRIBUTOR side, does it have spark? (don't pull it off the coil side- it can kill the coil.)
Make sure the screw is thru the side to the breaker plate. Went thru this with a friends car. Good power to the coil and points, no fire. A small thing but it will drive you nuts!! jerry
Update. I just got back from his place. He has 12V at the points. No fire coming out of the points. Changed condensor, no diff. Checked continuity from the case to the plate showed 010 ohms. Changed coil as well. No diff. Explain to me what is supposed to be insulated from ground? I know the stud (power) is supposed to be insulated, the plate is supposed to be grounded to the case, what about the points themselves? Grounded to the plate? It's been 20 years since I have owned a points distributor. The guy he bought the car from was trying to build a 1000 point showcar and disassembled everything, so we are not sure what he has done to the distributor. It's all nice and shiny and painted. He may have something grounding out in the case of the distributor.
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