Well it doesnt suck, but I dont think it works.
After adjusting the valves on the weekend, I was resetting the timing, adjusted the idle to 1400rpm as per the book, disconected the vac advance hose from the dizzy and the idle didn't change. Plugged it and the idle dropped and was really rough (compared to before).

1. So is the vac unit dead?
2. If so are they all the same for different dizzys/years??
3. Should I just give it more timing advance, till I sort it out???

My car is an early 71'. TIA Beaner7102

1. As mentioned on the other board, all you have to do to test it is to suck on the hose attached to it and see if it holds a vacuum. If not, its dead. Plug the port on the carb/manifold.

2. I searched high and low for information on vacuum modules and could not really find definitive information on part numbers/distributors/model years. So, I just assumed that the vacuum modules were similar enough in operation, and the differences were located in the distributor's advance mechanisms. So I bought that on on carpartsteam.com, but it's mount hole didn't line up, so I drilled it to fit.
3. If you have a Weber, I've read that they like as much advance as you can give it while still running well.

Good Luck.


Weber advice from Paul and Matt at Maximillian Importing:

BASIC CARB TUNING RULES:
Rule 1: you want the car to idle as lean as possible
Rule 2: Don't sacrifice smoothness for leanness though!! Lean it out (by tightening the idle mix screws) until it starts to lose it's smoothness - then back out the screws 1/2 turn.
Rule 3: The lower the idle speed - the leaner it can / needs to be, if you're
raising the idle speed - make a tiny corresponding enrichment at the screws.
Rule 4: I've always let my cars idle a bit high - maybe 950 -1000rpm. they
just seem to "settle in" around this when mixture and speed are ping ponged back and forth. trying for the perfectly smooth factory 850rpm idle in a 25 yr. old car, is like searching for a rust free 3.0 CS coupe - It rarely happens!
Rule 5: TIMING: You want as much ignition / distributor advance as you can stand - as long as it doesn't ping at full throttle up hills or at 3000 rpm w. pedal to the floor - you'll get the most performance from more advance.
a. When you advance the timing - it will generally raise the idle speed.
Make corresponding idle speed adjustment back to 900-1000- then corresponding
(leaner) mix adjustment.

b. Bigger carbs just seem to like more "initial" advance at idle - it improves the throttle response and smoothness off idle.

Now go to it! be patient, be methodical, and do one step at a time to avoid too many variables!!!


More timing comments:
Have you tried advancing the timing yet (beyond the stock setting)? In every case we've had where there was a problem similar to yours, increasing the timing a bit has smoothed it out. My experience has led me to completely abandon the timing light as a tuning tool for the '02.


My method for adjusting the timing is to basically turn the distributor counter clockwise until the idle get rough and then just back it off until it smoothes out. Then go drive up the nearest hill and 4th gear and listen for pinging, then, if it pings, back off the timing until it goes away. Fresh points and stuff couldn't hurt, but I'll bet the timing will fix it.

Thanks mmiller, it has a brand new Pertronix (was points), cap, rotor, plugs and leads in it. It is a Weber 32/36 (CD's jets), at the moment it idle mixture screw is 1 1/2 turns out (not 2 ½ as per Best Lean) which is to the rich end, but I will redo this when I give it more advance. It doesn't appear to be lacking on performance, it is the original motor with about 300,000 miles on it (compression numbers all over the place), the new plugs etc. have given it a boost in performance, and its economical, I did a 5hr drive after valves, timing etc and got 25mpg, city driving this week has been about 20mpg. Thanks again for your pointers. Beaner7102