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Re: Dieseling

Subject: Re: Dieseling
Date: Thu, 28 Dec 1995 21:04:54 EST
-- [ From: Bob Nogueira * EMC.Ver #2.10P ] --

I'm no expert but the Weber vacuum port run to the backside (of the
throttle plate, thus vacuum is supplied only after the throttle is
opened a little. I'm not sure how an anti run on valve works, but if
vacuum is needed after the car is at idle,  you won't get any. This 
would appear to kill your Solution # 2.
This would appear to make solution number one the way to go. 

Bob Noguiera
                        "There  is nothing new in the world only
( I'm taking a short break from rebuilding a pair of SU s so I can
replace my god awful Weber) 

I-------- REPLY, Original message follows --------

> Date: Thursday, 28-Dec-95 08:07 AM
> From: James Fischer            \ Internet:    
> To:   Bob Nogueira             \ PRODIGY:     (NKED65A)
> Subject: Re: Dieseling
>     Craig Wiper asked:
> >I just decided to throw my Weber 32/36 downdraft back on the B. My
> >don't like the cold weather much. My question is: Is there an easy
way to
> >prevent dieseling when cutting the ignition with these carburettors?
> >the SU's many vaccuum ports I am able to prevent the dieseling by
> the
> >anti-runon valve attached. But with the Weber, I only have one
> port,
> >which attaches to the vaccuum advance on the distributor. 
>     1)  One could drill and tap the Webber's intake manifold 
>         to accept a second vacumn line (most of the conversion 
>         kits I have seen include a round flat spot on the top of
>         the manifold for this purpose), but this would force you 
>         to remove the manifold to make the modification.
>     2)  You might want to experiment with a Tee fitting on the
>         existing vacumn line, and connect both the vacumn advance
>         AND the anti-run-on valve, since the net pressure should
>         roughly equalize regardless of the details of the 
>         connections.  Please note that I have no idea of the net
>         effect of using an anti-run-on valve with a Webber.
>     3)  To my knowledge, the vacumn port on at least the Webber 
>         down-draft carbs is a very stange beastie when compared 
>         to the usual set-up with dual SUs.  The vacumn is a 
>         steady (manifold) pressure with the SUs, but the Webber 
>         carb vacumn port provides a "pulsed" vacumn, which tends 
>         to frustrate the vacumn advance mechanism.  I do not use 
>         the built-in vacumn ports on either of my dual Webber 
>         DGVs, I use a vacumn line on the manifold itself.
>  www.ill//somebody ple@se expl@:n th:s wwweb @address.bu:s:ness?
>  james fischer             

-------- REPLY, End of original message --------

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