[T2] Pairing distributor with carburetor

[Lourd Baltimore]

Brian,

Yes, the 009 distributor will give a flat spot especially with the 34PICT.  The 009 is a non-optimal distributor pretty much any road-going VW engine. Assuming the Beetle's engine is an otherwise stock 1600 twin-port, then you want a DVDA (dual vacuum dual advance) or SVDA (single vacuum dual advance) distributor.  This article explains this: http://www.vw-resource.com/carb_dist.html

There is a vacuum port on the 34PICT-3 on the left just above the big bypass idle adjustment screw.  You can see it labelled on the first photo here: http://www.angelfire.com/tx2/ntnb/Carb_Instructions.htm

If this has not been blocked, then your friend may want to plug this port which _may_ help a little with the flat spot.  Some folks use richer jetting to help as well.  You should note that these solutions are really just attempting to compensate for the limitations of the 009 distributor.
As for timing the 009, this article give a good guide on setting the timing: http://www.vw-resource.com/009_dizzy.html
The important bit is to note that setting the max advance is more important that setting the idle advance for the 009.

However, the better solution is to utilize this port with some sort of vacuum-mechanical distributor as VW intended with the 34PICT.  This probably means a SVDA distributor as I believe DVDA models are getting harder to come by and the SVDA works well with the 34PICT.

The vacuum signal from this vacuum port on the carb connects to the vacuum advance can on the  SVDA distributor.  This can kicks in the ignition advance just off idle and during part-throttle operations.  This will eliminate the flat spot and should give better MPG for part-throttle cruising.  Once RPMs are up the mechanical advance kicks in.  The 009 distributor only has the mechanical advance so ignition advance does not kick in at just off idle and low-throttle operation, hence the dreaded 009 flat spot until the RPMs are up.

For STOCK applications this list from the Old Volks Home will tell you what which distributors and timing settings to use with your vehicle:  http://www.oldvolkshome.com/ignition.htm
However, who knows what configuration your friend's Beetle (and probably most VW's on the road) are using.  In which case generic SVDA tuning procedures should be fine (see below).


So, in short...
The 009 is not the best distributor, but adjustments can be made to make it work better with the 34PICT.  Possibly enough for your friend to live with.
The better solution is to get an SVDA distributor and use this tune-up guide to get everything running well: http://www.vw-resource.com/tune_up.html
This guide will also work for the 009 as well.
I ditched the 009 on my bus for a used SVDA for £25.00 and then followed the the tuning guide above.  I'll never go back to a 009 if I can help it*.

Sorry for the ramble.  I'm sure someone else will disagree and give you other advice.  Listen to them as well and make the best decision for the performance you want the money you have.

Cheers,

Josh


* I'm getting to get my current 1600 twin port rebuilt.  As my bus is my daily driver I bought a cheap used engine to drive in the meantime. It'll be ready to drive today.  This engine has a 009 with a single Weber progressive carb...

.






________________________________
 From: "beney14574 at aol.com" <beney14574 at aol.com>
To: "type2 at type2.com" <type2 at type2.com> 
Sent: Friday, 6 December 2013, 2:24
Subject: [T2] Pairing distributor with carburetor
 

Hey,

A friend took his 74 Beetle into "mechanic A" because it broke down somewhere on Rt 14 in SoCal. He replaces the carburetor to PICT 34. 

He brings it to Mechanic B, for a different....
Mechanic B points out the distributor (an 009) is not compatible with a PICT 34. It will always sputter during acceleration.

Is this true?  If so, what distributor should be used? Or can we just retard or advance the timing to compensate?



Clear Skies,

Brian Eney

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