engine and drivetrain ?'s about vacuum line after de-smogging 75'w/Solex DIDTA

[massimo]

Hey guys, I hope your day is going good and as always, Thank You for your attention to my posts. I always get good, experienced answers!

Now, The project is coming along fine. Pulled smog stuff last night, capped ALL vac lines, including advance/retard on distributor canister. I left the fuel return line that goes into the bottom of the carb(this is the vac. connection on the DIDTA that faces the front of the car).

Now here are my questions:

Why would I need to run advance at all, since this is a manual transmission?

If advance is recommended, where would it go, dashpot or carb?

Again, all this applies to a 1975 with advance/retard distributor and using a Solex DIDTA. I have a 32/36 DGAV that will go on, but I need to rebuild it, so if you could comment on the same question but apply it to the situation with a 32/36 DGAV.

Thanks and I look forward to your input....Frank

P.S. I am thinking about renaming this car from Marie to

The Barbarian...what do you think?

[Emyers]

Frank,

You could run with the Vacuum advance disconnected, and when you install the 32/36 you are pretty much forced to go without, as the Weber does not have the proper vacuum port. The Solex, has I believe, the correct port i.e taking the vacuum above the throttle butterfly, to activate the vacuun advance mechanism. I would connect the advance to the carb port, provided the vacuum capsule is in fact operational and drive.

Earl

BMW CCA #18736

1974 02Lux

2002 M Roadstwer

1972 Volvo 1800ES

[TobyB]

Actually, if it still works, hook the vac advance up to the port on the

base of the carb.

What happens is that the port is at atmospheric at idle, but as soon as you

open the throttle just a bit, it advances spark quite a bit, to help burn the slow-

burning lean, thin mixture for cruise and slow- speed running.

As you open the throttle, that vacuum signal decreases, letting the distributor

retard the spark and prevent early ignition of the richer fuel- air mix

you're now giving it.

So you get 2 benefits- better economy at part throttle from more spark advance,

and better idle.

And many Weber carbs DO have this port- if you look, it's a brass nipple

that draws signal from right at the throttle plate position when it's closed.

fwiw,

t

[massimo]

Hey guys, there's two ports on the base...is it the port under idle air screw or the one under the bowl?

[Emyers]

An easy way to determine if the port is taking the vacuum signal from above the throttle, take a can of carb cleaner with the spray tube and spray some into the vacuum port. as you spray look into the throat of the carb for the cleaner to exit inside the throat above the butterfly.

Absolutely correct reference the statement that some Webers have a port located to source the vacuum signal from above the throttle plate, the 40/40 DFAV I am running on my 02 does as well as the 38/38 DGAS/ES, the 32/36 does not, at least none that I have seen.

Earl

74 02Lux

02 M Roadster

72 Volvo 1800ES

[massimo]

Hey Earl...Is your M roadster the 300HP version?

[Emyers]

Yes sir, S54, 315 hp. Stupid fast.

Earl

[massimo]

Right on!