Giving Up On Vacuum Advance Options

[Ansbacher]

Car = '74 2.0 Liter, Dual Dellorto Carbs

For years I have been 'adequately" running an 009 mechanical only distributor. Finally took the pervasive advice out there to go with a vacuum advance dizzy from a 1.8L 914. Since only one of my Dellorto carbs had an existing vacuum port (ported type), I had to drill a port in my other one (no problem there). I used good quality anti-pulse valves in the lines and measured a maximum vacuum of 12 inches of mercury with partial throttle.

Installed the 1.8 dizzy and set the timing, first without the vacuum lines attached. To satisfy my usual 30-32 degrees at 3500 RPM, the idle timing had to be at about 5-6 degrees (quite low for my setup which is happier at about 10 degrees. When I attached the vacuum lines my timing at 3500 RPM went sky high into the 40s. This seems way too high. Is this normal? Overall, I found the car to run better without the vacuum attached and the carbs plugged off.

Am I doing something wrong here? I don't like the numbers I am getting. Everyone said this was the way to go with carbs, but I am not seeing results. Advice appreciated.

Ansbacher

[nditiz1]

I can't find the diagram right now, but someone posted the different distributors and curves. There are 2 or 3 I believe that can provide the curve you need which is a total mechanical advance of around 20 degrees (10 base + 20 full adv = 30 total timing at 3500)

Before using the 123 on my 2.0 I had the Mallory Unilite. It had swapable springs which you could change the spring rate and change the total adv.

While the 123 is costly at ~$450. You will never need another dist for your engine. The only other option is to source a used factory one or Mallory.

@Tbrown4x4 you are doing your setup an injustice by running that 009. If that 205 AA is listed as correct for your engine, get that cleaned up and working.