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<x-charset ISO-8859-1>On 15 Sep 2002, at 23:22, Dave Hall wrote: > The only stock Type 3 distributors where timing is done with hose(s) on is > the twin vac on the dual carb (ie the one yours should have). Whether it > makes a difference in every case I don't know, but I can't see why they > would bother to get you to remove the hose if it wasn't desirable. I think the admonition to remove the hoses is just left over from some earlier era, since the vacuum advance does nothing at idle on any system that I am aware of that uses a dist with mech & vac advance, but not vac retard. > NOTE: The vacuum unit does not advance the ignition timing. It retards the > ignition 7° at idle speed and returns the plate to the static position after > throttle opening." I assume this just refers to the retard portion of the vac adv/retard mechanism. > There's a bit more to the design, as the two ports have different bores, so > there is a gradual change to the plate position. This is probably the key here. The interplay of the vac adv and retard is probably pretty subtle, but I believe the vac retard goes away instantly once the throttle is opened, leaving the vac advance to come on slowly at higher rpm and lower throttle. I don't expect either of them to be doing anything at WOT. - Jim Adney jadney@vwtype3.org Madison, WI 53711-3054 USA ------------------------------------------------ To unsubscribe, E-mail to: <type3-off@vwtype3.org> For more help, see http://vwtype3.org/list/ </x-charset>