So long as the SP vacuum-only distributor isn't giving too much advance at idle (easy to check, at a normal idle speed the timing shouldn't change when the vacuum advance line is disconnected) it's fine on a singleport - but the ported vacuum signal is greater from a 34PICT-3 than it is from any of the 30PICT carbs, so it's not a good idea to use one on a dualport unless you're prepared to fiddle with the return spring tension to dial it in for that application. The 0 231 178 009 distributor gets a lot of bad press, blaming it and it alone for a "flat spot" on acceleration. It's true that an SVDA or DVDA distributor will usually alleviate the problem to some degree (any engine will respond to more timing advance up to a point - the problem is knowing when to stop before it causes damage), but the root cause is lack of sufficient intake manifold heat...and it's worse on a dualport because the larger diameter of the intake tract reduces flow velocity. VW acknowledged that problem on `74 engines (dual preheat pipes) and on `75-up Euro-spec carbureted engines (a much larger preheat pipe, ~3/4"). I've never had a problem getting a 34PICT-3 to run OK with an 009 provided the manifold heat is good and the thermostatic aircleaner is working properly - WITHOUT plugging the throttle plate hole or richening the jetting more than one step...tampering with the carb like this is the wrong way to address the problem, it's all about intake temperature and off-idle timing.
--- [EMAIL PROTECTED] wrote: > Marc, > Could you clarify your last post. The thread was > about a problem > with a 34-Pict-3 carb (dual port); so can I assume > you're saying not > to mix and match VW parts of differing applications; > specifically the > single port vacuum only advance distributor with a > 34-PICT-3. Or is there > a problem with the single port Vacuum advance > distributor even in > the stock application on the single port engine. In > other words, do you > suggest using a 009 distributor instead of a stock > vacuum advance unit > on a single port motor (stock configuration)? > > Thanks, > Brian > > > ----- Original Message ----- > From: "marc vellat" <[EMAIL PROTECTED]> > To: "Air-Cooled Volkswagen Discussion List" > <[email protected]> > Sent: Sunday, May 06, 2007 7:43 PM > Subject: Re: [vintagvw] Carberator Problem? > > > > If you have a stock DUALPORT distributor it's > worth a > > shot. The vacuum-ONLY type used on singleports has > its > > own issues - it'll most likely provide too much > > advance, too soon, which can harm the engine...I'd > > choose the 009 over it. > > > > --- Eric Larson <[EMAIL PROTECTED]> wrote: > > > >> Would changing the distributor really make that > much > >> of a difference? I'm running a 009 cent only > >> advance. I've heard people say that the cause > >> hesitation, and I've heard others say they are > >> better. Maybe I'll put the stock vacuum advance > on > >> and see how it works. I'll double check all the > >> typical vacuum leak areas like you said. I might > >> have missed something. > >> > >> Eric > >> ----- Original Message ----- > >> From: Mike<mailto:[EMAIL PROTECTED]> > >> To: Air-Cooled Volkswagen Discussion > >> List<mailto:[email protected]> > >> Sent: Saturday, May 05, 2007 8:27 PM > >> Subject: Re: [vintagvw] Carberator Problem? > >> > >> > >> The accel pump adjustment is to compensate for > >> slight differences/wear in > >> the accelerator pump itself and linkage slop > .... > >> If I remember from my > >> rebuild kit and Bently manual, the spec on the > >> pump is a certain number of > >> CC's of fuel for a given number of "squirts" > with > >> the pump activated thru > >> the throttle linkage. If you get too much total > >> fuel, you adjust it back and > >> vice versa. > >> > >> The stock main jet on the carb is a little on > the > >> lean side; this was part > >> of the first attempts at exhaust emissions > >> reduction on the engine. The > >> stock main is a 127.5 and I replaced it with a > >> 130....much better. > >> > >> Like Mark suggested, another possible cause for > >> the stumbles is a blocked > >> manifold heat riser or one with insufficient > flow. > >> If you have a stock > >> muffler (or an aftermarket with the heat riser > >> pigtail) make sure the end of > >> the pigtail is centered in the exhaust outlet > >> (remove the left tip, look > >> into the muffler and you should see the outlet > end > >> of the pigtail centered > >> in the opening....if it is cocked slightly, use > a > >> big screwdriver to center > >> it... muffler exhaust flow around the end of > the > >> pigtail helps draw the heat > >> riser exhaust flow. Check to make sure your > center > >> manifold to cylinder head > >> riser rubber couplings are not leaking. Check > to > >> make sure your throttle > >> plate bushings are not leaking air (unhook the > >> return spring from the > >> throttle arm and try to move it up and > down/fore > >> and aft....anything but the > >> slightest hint of movement means you have worn > >> bushings). > >> > >> mike > >> 73T1 > >> > >> > >> > >> ----- Original Message ----- > >> From: "Eric Larson" > >> <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>> > >> To: "vintagevwlist" > >> > > > <[email protected]<mailto:[email protected]>> > >> Sent: Saturday, May 05, 2007 11:37 > >> Subject: [vintagvw] Carberator Problem? > >> > >> > >> > What does the adjustment on the accel arm of > a > >> 34 Pict -3 carb supposed to > >> > do? I assume it makes the accel pump squirt > >> faster when you hit the > >> > throttle? (I have the non-alternator carb > that I > >> modified to work.) > >> > Problem is - hesitation. it hesitates after > it's > >> warmed up. The hesitation > >> > isn't there when you rev it in neutral. Can > you > >> adjust that out with the > >> > accel arm adjustments? Do I need bigger jets? > >> > > >> > I'm also running 33" mud tires, which I'm > sure > >> doesn't help things. They > >> > really kill the power. No power off the > start, > >> and it hesitates when the > >> > choke turns off. Anything below 2000 rpm is > >> slow. Descent power till about > >> > 3500 rpms, then slow again. Should I try > >> different tires and see if the > >> > flat spot disappears? Or should I adjust the > >> carb some more? I have a set > >> > of Kadrons. Would they help with the > tire/power > >> problem? Any ideas are > >> > appreciated. > >> > > >> > Eric > >> > > _______________________________________________ > >> > vintagvw site list > >> > > >> > > > [email protected]<mailto:[email protected]> > >> > > >> > > > http://lists.sjsu.edu/mailman/listinfo/vintagvw<http://lists.sjsu.edu/mailman/listinfo/vintagvw> > >> > > >> > >> _______________________________________________ > >> vintagvw site list > >> > >> > > > [email protected]<mailto:[email protected]> > >> > >> > > > http://lists.sjsu.edu/mailman/listinfo/vintagvw<http://lists.sjsu.edu/mailman/listinfo/vintagvw> > >> _______________________________________________ > >> vintagvw site list > >> [email protected] > >> http://lists.sjsu.edu/mailman/listinfo/vintagvw > >> > > > > > > __________________________________________________ > > Do You Yahoo!? > > Tired of spam? Yahoo! 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