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

[72hardtop]

Don't attempt to 'T' the lines together. Pull off (1) port only pref. #4 closest to the distributor. Put the anti pulse valve as close to the carb as possible (arrow points to carb).

T'ing the lines will increase pulsing and lower the overall signal greatly.

be sure the distributor is clean and greased properly (advance plate). Use Super lube.

You should have no additional vacuum advance at idle once the hose is hooked to the distributor. Set timing to roughly 28-30 degrees fully advanced ~3200rpm's (hose off plugged). Ideally you should be getting 7-10 degrees additional vacuum advance hose attached.

Blipping the throttle with a vac gauge should show the needle flicking to 8-10in.

[Ansbacher]

Don't attempt to 'T' the lines together. Pull off (1) port only pref. #4 closest to the distributor. Put the anti pulse valve as close to the carb as possible (arrow points to carb).

T'ing the lines will increase pulsing and lower the overall signal greatly.

be sure the distributor is clean and greased properly (advance plate). Use Super lube.

You should have no additional vacuum advance at idle once the hose is hooked to the distributor. Set timing to roughly 28-30 degrees fully advanced ~3200rpm's (hose off plugged). Ideally you should be getting 7-10 degrees additional vacuum advance hose attached.

Blipping the throttle with a vac gauge should show the needle flicking to 8-10in.

With this distributor, there is no way I can set timing to 28-30 degrees. If I do, it puts my idle timing at 0 degrees or less, making it impossible to run good at idle. Also, I found that T-ing the lines from both carbs smoothed the vacuum out.

Ansbacher

[72hardtop]

Don't attempt to 'T' the lines together. Pull off (1) port only pref. #4 closest to the distributor. Put the anti pulse valve as close to the carb as possible (arrow points to carb).

T'ing the lines will increase pulsing and lower the overall signal greatly.

be sure the distributor is clean and greased properly (advance plate). Use Super lube.

You should have no additional vacuum advance at idle once the hose is hooked to the distributor. Set timing to roughly 28-30 degrees fully advanced ~3200rpm's (hose off plugged). Ideally you should be getting 7-10 degrees additional vacuum advance hose attached.

Blipping the throttle with a vac gauge should show the needle flicking to 8-10in.

With this distributor, there is no way I can set timing to 28-30 degrees. If I do, it puts my idle timing at 0 degrees or less, making it impossible to run good at idle. Also, I found that T-ing the lines from both carbs smoothed the vacuum out.

Ansbacher

You need to limit the advance (tweak the stops) the Type-4 loves some initial advance roughly 10-12 initial. You only need 1 vac line.

The additional advance (vac advance) will be load sensed. Load being throttle position. Get a bung welded in and start tuning with an LM-2.

Part throttle....16-17 AFR

WOT....12.5 - 13.2 or so