TheSamba.com :: View topic - Are there two versions of Solex PCI 28 Carburetor

Mon Sep 26, 2011 2:19 pm

Solex PCI 28 was introduced on Oct 1 1952 (start of Zwitter prod.) Some sources claim it was introduced on Jan 15 1953. It may be that it varies by model and country. During this time all engines were equipped with the Bosch VE 4 BRS 383 distributer that has no vacuum regulator. A distributer with vacuum regulator was not in use until the start of the 36 Hp engine in Dec 21 1953.

All of my 3-4 Solec 28 PCI carburetors have an inlet for a vakuum pipe in the right side of the manifold facing the generator. My guess is that Solex did not make an exclusive version for the period Oct 52 until Dec 53 and that these carburetors were shipped with a plug in the inlet.

Would be glad if anyone could confirm this or tell me that I have to start looking for a carburetor that does not have the vacuum connection

Mon Sep 26, 2011 2:59 pm

Aren't the ones on buses minus a vacuum opening? I seem to remember a post in the bus forums where a picture of one of these carbs with no port is shown.

Most buses seem to have a screw plugging this opening since the distributor has no vacuum advance.

Found the picture:

Mon Sep 26, 2011 4:05 pm

interesting picture. The place where the port normally is drilled is clearly visible. That means that there are only on type of mold for the PCI 28 but that there might be a version where the hole was never drilled. Find it unlikely that that type 1's all had carbs like the one in the picture. still believe that a screwplugg is more likely to be the original for zwitters and most of 1953 production.

Mon Sep 26, 2011 4:26 pm

There are two versions of this carburetor. One without any casting for the vacuum port which is the first generation. The next version had the casting for the vacuum port, but no hole or threads like the one pictured above. Then finally, in December 1953 the hole was added to the casting.

Now you know 8) I have seen both versions by the way.

Here is the version with no casting....

Mon Sep 26, 2011 11:51 pm

Thanks for the info.

As you said, now I know. I'm building a engine for a Zwitter and as everybody else I like to get it as correct as possible. I can always use one of the later ones to start with. Putting a plug in the existing hole on one of my 28 PCI's. It will be a minor deviation from the 100% true build and I will start looking for the real thing like the one in your picture.

Tue Sep 27, 2011 8:49 am

nlorntson wrote:
Found the picture:

Note the earlier carb body has a thicker ring around the VW emblem. Later 28 PCI carbs have a different emblem with a thinner outside ring.

Tue Sep 27, 2011 10:19 am

There are actually at least 7 different versions of the carburetor base on what I call the early 28PCI carburetors (through approx. SN 2,000,000) and several more on later versions. I've attached pictures of the first three below. The earliest had no casting as Eric pointed out and was used on the Zwitter from Oct. '52 probably through mid-year '53 and includes carburetors with SN through about 770,000. The next version through approx. SN 990,000 had the casting for the vacuum port but it was not drilled out because VW was not yet using a vacuum advance distributor (for information on these see my website--www.vintagewerks.com). It had nothing to do with bus versus beetle use. After Dec. 21, 1953 with introduction of the first generation 36hp engine, the vacuum port was drilled out and threaded for the vacuum line which was supplied on beetles equipped with the dual advance style distributor but was plugged with a brass set screw for the buses as shown in the photos. As Nancy pointed out the VW emblem on the side of the carburetor on these early versions was small in diameter and thick--it remained this way through approx. SN 1,100,00 after which it went through several different iterations. I wish I could be more specific with SN and dates but I haven't been able to find anything in detail other than what I have observed while rebuilding the many carburetors that have passed through my hands.

Fri Dec 16, 2011 5:04 am

You are correct about the 3 versions of the early 28 pci. I have a version 2 with the undrilled vacuum port. What no one has mentioned is none of the carbs before June 1955 have the 28 PCI logo on the bowl. Those pre 55 carbs are also getting hard to find.

Fri Dec 16, 2011 8:10 pm

also some have a threaded inlet for the metal gas line and others have a slip fit for the rubber fuel line.

Fri Dec 16, 2011 8:19 pm

Ummm the slip on hose was much later. I know the 40 hp had it. Not sure about the 28 pci ever had it. I think the 28 pic was the first. I'll have to research the exact time. I never saw a 28 pci with the push one hose. Check it out. I'm alway willing to learn. I'm pretty sure it started with the 40 hp and the 28 pic carb. Much different.

Fri Dec 16, 2011 10:33 pm

The Bus "bastard engine" has a 28 PCI with a push-on connector.

From this thread
http://www.thesamba.com/vw/forum/viewtopic.php?t=187275
Here's a post with a photo
http://www.thesamba.com/vw/forum/viewtopic.php?p=5732319#5732319

Photo:

Sat Dec 17, 2011 6:14 am

I never saw that before. Although I never owned a bus. Am I correct though, the bug never had a 28pci carb with a push on??

Sat Dec 17, 2011 10:36 am

As far as I know - No but I cannot be 100% sure myself.

Sat Dec 17, 2011 3:39 pm

I've never seen a 28PCI with a push on fuel connection. Not something that didn't look like an obvious hack anyway....

Sat Dec 17, 2011 5:02 pm

Here's a photos if from the Feb., 1960 Bus Owner's Manual as well:
http://www.thesamba.com/vw/archives/manuals/feb60bus.php

Also note the unique fuel pump design.

Manual spec. page that lists 28 PCI:

Fri Dec 23, 2011 10:57 am

Beetle "111 standard" models that had the 36hp "fresh air heat" motors had the 28 PCI with the "push on" fuel connector.

Fri Dec 23, 2011 11:51 am

Thats all new to me. The 36hp on the 60 bus has a 40hp block and fuel pump.
Learned something new today. Thanks.