Finally had an opportunity to work on and drive the truck today, so I went out and bought a timing light with an advance dial and then marked TDC on the flywheel with white paint (the line between the UC mark). Drove around for about 30 minutes, so the engine was good and hot, disconnected the vacuum advance, plugged the vacuum advance port, hooked up the tach, vacuum gauge (to the wiper port), and put the timing light to #1 wire.
So with the timing light, the blind man (me) now sees… Timing at idle was 15 degrees! So the engine probably was fighting itself and may explain the bumping it was doing. I checked the timing at 2,000rpm and it showed 30 degrees advanced. When I flipped to the #6 wire, I got the same readings for both idle and 2,000 RMP. So much for timing by anything other than a timing light. HRL, your measuring and cutting analogy was well put. I'm at least now measuring with a tape measure, marking with a slightly dull #2 pencil and cutting with a Bowie knife, just need more practice to graduate to micrometer and scalpel.
I adjusted the points and got a dwell reading of 41.3, and dialed in 9 degrees of advance at idle. At 2,000 RPM it was about 25 or 28 degrees, but it was hard to tell since I was doing it without a helper (needed three arms and another set of eyes). Took it for a spin and it ran great with no chuffing sounds. I’m guessing with the overly advanced setting along with a few tight valves caused intake and exhaust to rush past the partially open valves and caused that chuffing sound? The engine was not bumping around and the vacuum was solid. Valve lash after the 30 minute drive was good, with no tight valves at .006 intake and .018 exhaust.
Thanks again for the help.
mark
