On a two hour cruise Saturday engine started skipping a beat hear and there. Was kind of annoying then got worse over the weekend so I thought I'd try to fix it. Here's what I've done so far. What have I missed?
1. Monitored spark coming out of coil while driving. Although not smooth, misses in spark didn't seem to correspond to engine misses.
2. Replaced the condenser with new one that tested within specs (since that's the easiest fix). Didn't help.
3. Checked for voltage at battery side of coil. That was good.
4. Checked all of the sparkplugs and cleaned them. Checked spark in each wire to each plug. Most were smooth and consistent. Some were irratic but did not seem to correspond to engine misses.
5. Removed the distributor and dismantled, cleaned and lubed and checked all shaft/bearing clearances for any wear. All were good. Replaced the rotor and points, double checking their gap. Checked for their proper operation at distributor side of coil with test light. Light went on and off appropriately indicating points were opening and closing. Didn't help
6. Tried different timing settings. Didn't help.
7. Bypassed the resistor in case it was the problem. Didn't help.
[Seemed the more I did the worse it got.]
8. Tested the coil that seemed OK but tried two other coils just in case. Didn't help.
[By this time the engine would hardley start and if it did would only run for a short time before dying.]
9. Checked for adequate fuel flow and pressure to carburetor. Accelerator pump was not pumping so replaced my Stromberg carburetor with a Holley 94, whose accelerator pump worked perfect, in case the carburetor was at fault. Didn't help.
So, here's where I'm at now: If I plug a spare spark plug wire into the bottom of the coil and hold it near a head stud nut I get consistent bright spark. But, if I plug in the wire to the distributor and put my timing light on it to monitor spark I get very sporadic spark, then steady once in a while enough to idle for a few seconds, then nothing and the engine dies.
What else can I do or check before removing the entire spark plug wire harness and replacing all of them? That is the hardest thing to do and my last resort only if you can't think of anything else.
Any ideas?
