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Re: Solex Vacuum Line Question

To: "WILSON,BOB (A-SantaClara,ex1)" <bob_wilson@agilent.com>
Subject: Re: Solex Vacuum Line Question
From: "John F Sandhoff" <sandhoff@csus.edu>
Date: Fri, 16 Mar 2001 12:08:47 -0800
It was written:
> My distributor is the non-smog type with both mechanical and
> vacuum advance.

The distributor is virtaully the same, 1600/2000/SU/Solex.
On 2000/Solex applications, the vacuum modulator is not used.

> Rallye says that the vacuum advance hose should connect to
> the carb, NOT THE INTAKE MANIFOLD.

YES.
Vacuum advance (and advance in general) seems to be highly
misunderstood. You want NO advance (mech or vacuum) at idle,
and only the mechanical advance comes into play at WOT.

The vacuum port provides zero vacuum at idle, increases through mid-
throttle, and drops off at WOT (because manifold vacuum drops off as
well!). If you use manifold vacuum, you totally screw up the idle advance,
and end up RETARDING the spark at partial throttle.

> But they don't say why or where to connect it when you have solex carbs.

Because if you have solex carbs it's not used.

On a stroker 1600 setup, I honestly don't know what is best to do.

> My front solex carb has a small diameter brass tube sticking straight up.
> Is this tube to be used for the vacuum advance connection for the
> distributor?

Stick a vacuum gauge on this port and see what you've got. Should be
zero at idle and increase thru mid-throttle.

> Then do I just plug up the 2 holes in the intake manifold?

Those are smog pump (thermactor injector) ports. If you've pulled
the smog stuff them yes you want to plug them.

-- John
     John F Sandhoff   sandhoff@csus.edu   Sacramento, CA

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