F engine general tune questions, weak stock ignition?

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Feb 9, 2005
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Here's a smattering of questions about my F ('71) state of tune, the stock ignition, and an alternator question:

1. The engine runs great for an old 6-cyl, carb was re-built by Jim C. several years ago, I just replaced the exhaust manifold with new gaskets all around, plugs, points, wires, timing, are all tip-top. Smog removed, non-US vac advance dizzy. Vac gauge reads strong 21 in vac at idle. When hot, the engine idles pretty rough, not like it's missing on any cylinders(like idling on 5, I know what that feels/sounds like), just a general roughness. the vac guage still pulls high vac, but the needle wavers slightly, maybe 1 in vac back/forth.

Q: Could this roughness be the weak stock ignition at idle, or maybe valves out of adjustment?

2. Just completed the PIA crank pulley swap for a 3-row pulley, for my upcoming PS conversion. Replaced the WP while I was at it with a 2F pump. Now, however, the alt does not align well with the WP/crank pulleys(WP and crank pulleys are perfectly inline with each other), and I am getting BAD growling noises from SOMEWHERE down there when idling. Sounds like a diesel. Much belt squealing also.

Q: Could this belt mis-alignment with the alt cause it to make bad (bearing?) noises? If I remove the belt to try to isolate the alt (see if the noise goes away), will the truck start/run on just the battery for a while?
 
On questions #1, I'd certainly check your valve adjustment, and since you didn't mention it, your timing. Both you can do within an hour.
 
21 inches of vacuum at idle is excellent. The wavering needle, when hot, could certainly be mis-adjusted valves...
With a good battery, your engine will start and run for hours without the alternator.
 
Thanks, dudes, probably about time I got around to those valves anyway.
 
Rough idle can also be timing scatter. Watch timing mark w/ timing light, see if it moves at all when idling. If there is random movement, then dissy bushings are shot. Common problem on the small-body points dissy.
 
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