Why did the mechanic say this?

On Fri, 24 Oct 2003 13:08:27 GMT, Mike Elliott wrote:

..well, *most* of the time when dual carbs are added (or even when no) the stock vacuum advance distributer gets tossed out and a cherap centrifigal advance only dizzy (the bosch 009) gets substituted in its place. This is because the dual carbs will put out an less than optimal vacuum signal than what is requirerd to operate the vacuum can on a stock dizzy (short for distributer...saves my lazy ass a liuttle typing....although typing this ex[planation of the shortcut has more than negated any percieved benefits....::rubs chin thoughtfully::) This is a quick and dirty solution, and actuallt not so bad with dual carbs because oif the short distance in manifold and straight dump to cylinder heads, a littl extra squirt of the accellerator pump can eleminate (mostly) the hesitation found in a stock carbed and manifolded (like that word??) engine when using a centrifigul only system. To use a stock vacuum advance distributor with dual aftermarket carbs requires finding a vaccuum can that is designed to work with the proper signal strength for your application, or to use a fully adjustable aftermarket distributor such as teh mallory unit. Due to expense of the mallory, this is not often utilized.....although it is a damn fuine soluytion and the benefits are many (better usable power, gas mileage, etc.) In general the only individuals who generally buck the trend towards simplicity and seek optimum performance for their VW's have traditionally been do-it yourself type enthuisiasts. So there is a very good chance that in many years of VW manitenance he real *has* never seen a vehicle with a set of aftermarket dual carbs come in with a vacuum advance distributor....

..Gareth

Thanks for the detailed and very educational response!

Mike "At least the mechanic didn't laugh!" Elliott

.................ahem.........It sounds to me like Mike is trying to say that it has A single weber IDF.......not dual weberS.

.........Glad I could help!

My ignorance. The carb is a dual-throat Weber IDF 40 something-or-other. Not dual carbs. Duh. What I know about cars I learned from my son's Hot Wheels.

Mike "How do you feed the squirrel?" Elliott

I think You Just found your tag Mike.............

I dub thee............"Squirrel"

( not really my place to, but it fits real well.)

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The vacuum advance curve must be matched to the vacuum source that you give it. When you replaced your carb you also replaced the vacuum source, so you no longer know what to expect the vac adv to do.

In fact, I didn't think Webers had vac ports, so I'm wondering where you've got this attached. There's a VERY good chance that you've got this attached to some place where it's doing EXACTLY the wrong thing for your engine.

I'd be puzzled, too. Your best best would probably be to just disconnect the vac advance.

----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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Oh yea with a centermounted carb, you may be experiebncing manifold icing. You should get the more expensive heated intake manifold if you haven't got one already. Common problem with centermounted setups. Low end is horrible but at higher rpms it would work well.

Jan

. . . [the mechanic]

Good thoughts. I'll take a look-see, but I bet I've just got centrifugal advance right now.

Mike Rocket J Squirrel Elliott

Bonus Question: Who were Gidney and Floyd?

Two Characters on Rocky and Bullwinkle...............That's the best I could find in less than a minute on a web search.

Remove "YOURPANTIES" to reply MUADIB®

Web search -- forgot to say "no Googling".

They were the mo> Two Characters on Rocky and Bullwinkle...............That's the best I