I have it in my car. What is the difference between that and vacuum? I read that it meant a smoother curve for engine timing, and Hot rod said that it kills gas mileage over a vac.
does it hurt performance? does it cause misses? my car misses a lot when it is cold, and in low RPMs it bucks like there is a dead cylinder.

I figured this can go in this board because the vac hose goes to the carb


Thanks for looking at this long one.
--Dan

P.S. If someone...me...did a sloppy job cutting ignition wires, what can that do. I noticed that my upgrade to 300+accels didn't do much. I used pearl sized dots of assembly lube to get the frikin ends thru the boots...can that foul the spark plug/distrib caonections.

 

If the old wires were working ok, you won't see much gain in a new set of wires, regardless of brand/type--plus upgrading the rest of the ignition would also help. You have both mechanical and vacuum. Mechanical advance simply advances the ignition timing as the rpms increase(via spinning weights and springs). Vacuum advance kicks in at part throttle conditions and helps mileage, efficiency, and keeps the plugs/combustion chamber clean. If you are worried about timing, put a timing light on it.

 

Personally I think vacuum advance is overrated and unreliable. I use mechanical only. Most people will tell you that mechanical only setups are for the strip only. I like mechanical only better even for the street....locked out setups are strip only

 

Mechanical advance adds advance based on engine RPM. Vacuum advance adds additional advance based on vacuum: the higher the vacuum (lower load) the more advance it adds, up to 10° or so.

I always run both "mechanical" (RPM-based) and "vacuum" (load-based) advance. Mechanical is essential for getting decent power; vacuum helps cruising (low-load) gas mileage. It does not affect performance one way or the other, except for light throttle maneuvers at highway speeds,which it improves.

An ideal timing curve for a performance type of motor would be a static timing of 8-12°; advance that adds to that starting at about 1200 RPM, and increasing to about 24-28° at 2500 RPM; and an additional 8-10° at high RPMs and low load. Without vacuum advance, you probably leave about 1½-2 highway mpg on the table.

Computer-controlled systems use tables in the ECM programming to accomplish the same thing.

Neither has anything to do with misfiring when cold. That's almost always because the mixture is too lean.

Yes, using any kind of lube with metal in it can cause ignition problems. The right thing to use would be silicone grease.

The only way a new set of plug wires will make your car run better is if your old ones are defective.

 

"Vacuum advance adds additional advance based on vacuum: the higher the vacuum (lower load) the more advance it adds, up to 10° or so. " Yes, but it adds no advance unless the throttle is open(ported vacuum). You may be able to make a little more power with the vacuum advance hooked up if the vacuum can is adding too much advance--to the point that you have to reduce the base timing to keep it from pinging. Best way to do it, imo is to run an adjustable vacuum advance. Unhook the vacuum advance and tune it for max power(or best et), hook up the vacuum can and adjust as needed.