QuestionI have a 1963 Nova with 194 CI L6 engine. I have rebuilt the carburator, replaced the plugs, cap, points and condensor (dwell is at 31). I still cannot get the engine to idle smoothly and there is hesitation upon acceleration from Idle. Any suggestions?
AnswerThe dwell should be at 45 degrees for a 6 cylinder engine, but you may have other problems than that. When you change the dwell, that will affect the timing, so get yourself a timing light and set that on spec also.
An 8 cylinder engine dwell setting is 28-32 degrees (lower number for new points), but a 6 needs much higher dwell setting.
You don't mention where you've got the timing set - make sure that is on spec - if it's too advanced, it will cause the symptom you've got.
If that doesn't cure it, I suspect a carburetor problem, but you may also have a vacuum leak.
Get yourself a vacuum gauge and test the intake manifold vacuum - if it isn't at last 18" at idle, start plugging off vacuum hose connections to see if you can find it. The power brake booster is one common leak source, but their may be many others in the heater controls, the PCV valve etc.
If you haven't done a compression test on the engine, it's a good idea - if you have a weak cylinder, you're chasing your tail trying to fix it with external measures.
It's not clear from your message whether this is an old problem or new, after the carburetor rebuild. If that's the case, I'm very suspicious of the carburetor - especially the acclerator pump for the "hesitation" - are you getting a healthy squirt of gas down the carb throat when you operate the accelerator linkage?
Let me hear what you think about these thoughts, and we'll take it further if you want.
Ultimately, you may have to take to so someone with an engine analyser to spot the problem if these measures don't find it.
Dick
