View original topic: 32 PCI Carb Vacuum Port
Stong Fri May 12, 2017 1:17 am


I am building a 40hp based motor for my 62 Bus. I was planning to use a pair of NOS Solex 32 PCI industrial engine carbs in a twin carb set up.

I was keen to use a large body (vacuum advance only) distributor as I have a couple of these in good condition and they suit the age and look of my bus and engine.

I'm assuming the carbs can be tapped to provide a vacuum signal for the distributor.

My questions are:
Where would you do this on the carb as shown? (On the blank boss just above the flange slightly to the right of middle on the picture? Or at the small plug that is located in the body just above the mounting stud on the left, or somewhere else?)

How big does the vac port need to be? Are there reasons why they were differ sizes on different model carbs used on VWs?

Can I take the vacuum signal from just one carb or do I need to draw from both?

Thanks for your help!


Lingwendil Fri May 12, 2017 1:42 am

On those they would have been drilled (not at the factory, only by speed demons and hotrodders) in the same location as they are on the 28 series, you can see a block off plug on this particular one as it was intended for use on the early transporter series-

Many of these would likely have been used with mechanical-only distributors, so I have only ever seen one that had actually been drilled out for the vacuum port, and if I'm not mistaken (I haven't played with any 36HP carbs for years) it would have been threaded either 6mmX1 or 8mmX1, although I can't help you on the drilling for the port very much, the port itself should intersect the edge of the throttle bore in such a way that it is closed off at idle and uncovered as the throttle begins to open, just as in the 28 and 30 series, but it would not have the upper fitting in the airstream for use vith a vacuum only distributor. This would make it more appropriate to use with an SVDA type distributor such as the VJU4BR8 (or 0231 115 040) due to the difference in vacuum signature. I would use an 019 or 010 type of distributor in lieu of modifying the carb, personally...

Stong Sun May 14, 2017 2:00 pm

Thanks Lingwendil!

I went searching and found a 28 PCI carb with the vac port as you mentioned. Shouldn't be too hard to replicate this on the 32 PCI as it has the blank boss already there!

I have a range of early distributors I could use on this motor including a VJ4U BR8 and a VJ4 BR8 . I like the look of the ZV/PAU 4R5 as it's classic 40hp. I can always swap to the early SVDA unit if the performance is not what it should be with the vac only unit and the distributor is the problem.

Lingwendil Mon May 15, 2017 4:55 am

I can tell you right now that the vac only distributor will not work properly at all with the carb, the vacuum signature is completely wrong for it. Your best bet would be the SVDA or mechanical for your application.

Powered by phpBB © 2001, 2005 phpBB Group