Don't know if its been said but just try running the car without the vacuum advance. My car ran like dog poo till I got the timing light and saw it was going to something like 40 degrees total timing with the vacuum line connected. With it unplugged it ran up to 30 total and runs grate! I think I ended up at 12 digresses timing to 32 total? Its been a while but I never did figure out what was going on. Might be the MSD box.
Here is the latest:
the biggest problem I'm having right now is trying to figure out how to get manifold vacuum. It has been very inconsistent. I spent about 20 hours last week just trying to get settings to work across the range. Nothing has been working like in the YouTube videos and internet descriptions.
Any thoughts?
Manifold vacuum is vacuum taken after the throttle plates, the carb will have a port for it, drilling a hole in the intake manifold will also create one. If you aren't gettign consistent vacuum at consistent speed/load you have a problem, usually valvetrain related IIRC. Do you have a diagnostic vacuum gauge? It's a somewhat necessary tool for messing around with carbed stuff.
Skervey wrote: Don't know if its been said but just try running the car without the vacuum advance. My car ran like dog poo till I got the timing light and saw it was going to something like 40 degrees total timing with the vacuum line connected. With it unplugged it ran up to 30 total and runs grate! I think I ended up at 12 digresses timing to 32 total? Its been a while but I never did figure out what was going on. Might be the MSD box.
That's how a vacuum advance distributor is supposed to work, the advance can adds advance at light load, lean running, high vacuum periods of operation (e.g. cruising and idle) when the engine will run cooler and more efficiently with more advance. The advance can won't effect timing at high load operation when you have little to no manifold vacuum, that's all on the mechanical curve, which is why you set total timing with the vacuum hose removed and plugged.
We have some progress!! The intake manifold for the carb setup was just a bit thinner than the efi manifold. This was causing the bolts to bottom in their holes just a hair before actually getting the manifold/gaskets fully tight against the heads. Added some washers, and finally we have consistent manifold vacuum! Fingers crossed that final tuning is close!
In reply to Lof8-
Those pesky vacuum leaks will cause a properly tuned carb to run like garbage. Hopefully the leak going away will help you out big time!
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