Have ignition miss and a little trouble pin pointing the cause. I have replaced plugs, wires, cap and rotor. Plugs are all dark but can't seem to find one that is worse or better than the others (motor is running rich, carb kit is ordered). No indication of arcing on cap or rotor. Have not done anything with points yet (likely won't either probably replace with an Pertronix Ignitor). Did a compression test on the engine and numbers are strong +/- 5 psi. Coil is stock style coil (UC12) I have tested it with a meter and I get readings of 1.3 ohms (primary) and 8.49K (secondary). <8500 ohms seems low to me. Can anyone confirm that number indicates a suspect coil? If the coil is to be replaced I will bump up the voltage and go to pointless conversion. Please let me know what you think.
Bad condenser/improper dwell will also cause week spark. If miss persists hook timing light to each plug wire and look for consistant blinking, if one is erratic that will be the problem cyl.
-- Edited by hawkeye5766 on Thursday 25th of September 2014 03:03:59 PM
measure primary winding resistance between the two posts. .35 to .55 ohms is considered good.
measure secondary resistence between either post and the main terminal. 8-12000 ohms is good.
I believe that 8-12k to be correct for my application and was mostly wondering if the fact that it would be at the lower end be a cause for concern. I have coil that requires an external resistor and I believe 1.3 ohms to be a good reading for my primary. I have heard of coils that have lower primary values, mostly high output ones. Thanks for confirming the numbers, I think I will change it out.
Bad condenser/improper dwell will also cause week spark. If miss persists hook timing light to each plug wire and look for consistant blinking, if one is erratic that will be the problem cyl.
-- Edited by hawkeye5766 on Thursday 25th of September 2014 03:03:59 PM
That timimg light idea is great. I will use that one. I was shown at one time how to do point set points on an old car I had, but not long after got the chance to upgrade to HEI off newer model for free. Never really had to mess with'em. I think I will go with pointless replacement in distributor and keep stock appearance. Thanks Hawkeye.
If going with Pertronix make sure your Dist bushing and Vacuum adv plate are in good shape. The pertronix uses the dist lobes to fire. Every time I hooked up vac adv Ing would cut out and backfire, found that the vac plate pivot was worn causing to much gap between the pickup and dist lobe. Just a thought.
If going with Pertronix make sure your Dist bushing and Vacuum adv plate are in good shape. The pertronix uses the dist lobes to fire. Every time I hooked up vac adv Ing would cut out and backfire, found that the vac plate pivot was worn causing to much gap between the pickup and dist lobe. Just a thought.
Yes, Pertronix. I'll look out for that. Hope to have time this weekend to install. Thanks again.
