28 PICT Carb Question

[txasylum]

I just rebuilt my 1200cc 40hp motor, but prior to it I had a slight hesitation from idle to full throttle. I do have the correct dizzy on the car and it is working, but I'm researching more on the carb. Thinking of buying a gallon can of carb cleaning solution to let it soak; although, I have taken this carb apart and cleaned it twice before.

BUT, in reading the 28PICT manual (posted elsewhere on here) I see on picture 11/36 the discharge tube in the venturi appears to be a spray; whereas, mine when I hit the throttle is a stream of gas.

Should it be a spray? Could this be my issue?

https://www.thesamba.com/vw/archives/manuals/looklisten_11/looklisten11_28pict_carburetor.pdf

[fl59bug]

How is the throttle shaft looking ie is it tight in the bore or is there play/wobble? Many of these og 28 pict carbs (and others I'm sure) develop wear in the bore and this will cause vacuum leaks and hesitation and generally poor performance.

I've got a pile of 28 pci/28 pict/30 pict carbs with worn throttle shafts which I cannibalize for parts. My rebuilt big-bore 40hp has a new empi 30-pict1 with auto choke and it runs pretty good so far. I consider these carbs pretty much a disposable item since I'm not set up to re-bush the throttle shafts.

Be careful if you decide to buy a "professionally restored and rebuilt" carb vs a new empi unit, as I've had bad luck with the former. My "rebuilt" 28 pict came to me looking real pretty on the outside but with a pretty good vacuum leak at the throttle shaft, a bad/sticky needle and float and the car would run out of fuel in the bowl chugging up hills. Others may have mixed results with the empi ones and I get that, but unless an individual is a pro rebuilder I recommend all the rest of us lay-folk buy a 30 pict and call it a day.

Just my .02 which others may or may not reject outright!

[txasylum]

When I was getting the car running after putting the new rebuilt motor in the car, I poured some gas down the throttle body of the carb. It did get wet on the throttle shaft. I did feel it and it was a little wobbly. I tightened it down a bit. Running normally it does not leak or get wet.

So from the sounds of that, I'm guessing it is leaking there? You suggest a new empi 30-pict 1? Will that match up to my dizzy that is matched to the 28 Pict?

I should add my car is a 6 volt. I just looked up the 30-pict 1 and it has a 12 volt choke.

[catahoula lou]

A stream of fuel is fine, as it shows no blockage. I swing mine so that it discharges on the side of the butterfly that rotates downward into the venturi, close to the edge, so that most goes directly into the opening venturi so that it can vaporize.

To test for air leaks, set a water spray bottle to shoot a stream of water, and then shoot at outside throttle shaft holes and anywhere else air might get in if not properly sealed. If you have an air leak at any location(s), the engine idle should decrease a bit and then you can solve your hesitation.

Best,
Thom
_________________
1 great wife
2 Catahoula Leopard Dogs (Mahogany Star and Spartan) - RIP Lucy, Braveheart, & Dusty!
1 1959 mango green Ragtop Bug (the "Mango")
1 1958 pantina red Lowlight Ghia (the "Chili Pepper")

Still looking for:
(1) My Dad's 1955 356 (he raced it amateur-class at Riverside and other courses during 1950s),
(2) My parent's black 1955 hardtop bug (CA license plate FWC 201 or FWG 201), and
(3) My parent's agave green 1957 ragtop bug (CA license plate LFK 734).

[heimlich]

What distributor do you have on your car? If you change out the carb you will need to make sure the signal for the distributor is correct.

You might also look at the Brosol H30/31 if they are still made.
_________________
www.vwnos.com [email protected]
Classic Brands. Classic Quality.
Not all parts are made the same. NOS OE/OEM parts made mainly in West Germany, Early Germany, and Early Brazil are where VW produced the best quality parts and best fitting products.
5% Off your order with coupon code: 5%OFF
Restored Distributors Available (<--Click here)

[fl59bug]

Ah - 6 volts still, ok.

I know WW sells both the 6 and 12 volt choke elements, but I'm not sure if the 6 volt one will fit snugly into a 30 pict 1 or not.

As long as the 30 pict 1 develops a strong enough vacuum signal, the distributor compatibility is less of an issue. On my setup (12 volt conversion, '65 40hp with 83mm P&C's) I'm running a quality 009 with the empi 30 pict 1 so vacuum signal isn't an issue. My engine purrs (knock on my head.. er wood, don't want to jinx it though!)

I would say if you can keep what you've got and track down the cause of the hesitation great, but keep the 30 pict (with WW 6 volt choke element) in mind if despite everything the hesitation continues.

In the interest of trying to make what you currently have work, here are just a few more tips that I can think of:

1) make sure you have a healthy squirt of fuel down the throat of the carb when pulling the throttle lever

2) make sure your jetting is spot on (the right size main jet - not too lean or too rich) and blow them out with compressed air or carb cleaner

3) rule out any vacuum leaks between carb and manifold and manifold and heads

[KTPhil]

I would also verify the vacuum advance is working to spec.

[txasylum]

Yes, I previously verified this. I can suck on the vacuum line and I watch it turn.

[txasylum]

I believe it is the Zv/ Pau 4 R 2. It is the match for the 28PICT and original to the car.

[txasylum]

The jetting is another one I wondered about. I messed with them before I did the engine rebuild, but not sure what to run or what should be in the 28PICT. I need to google again.

[txasylum]

I just read on JBUGS site when looking at the 30pict1 carb that it does not have enough suction for a SVDA, so I guess that won't work for me unless I change the dizzy.

[fl59bug]

I wasn't aware of the difference in vacuum signal between the 28 and 30 carbs.

Looking at my carbs for example, I will say that the diameter of the holes in the external portion of the vacuum port on both carbs appear very close in size, so the vacuum signal difference must be due to something internal to the carb?

A few photos of my 28 pict 1 and 30 pict 1:

30 pict 1:

28 pict 1:

With respect to the choke, I do see that my 28 pict 1 has a 12 volt choke fitted so it should be the case that if the 12 volt choke fits the earlier carb while also fitting the later carb, then the 6 volt choke should fit the later carb.

[tasb]

You do not have an SVDA distributor. These have both vacuum and mechanical advance. The R 2 is a vacuum only distributor= SVA.

The difference in the vacuum signal is a function of the distributor vacuum canister. The big cap canisters require 50 mm mm/Hg, while the later 40 hp 111 series aluminum distributors require a tiny bit more. They both deliver around 18 degrees of advance.

The later 113 series distributors have vacuum canisters that deliver around 25 degrees of advance at 65 mm/Hg for 1966 and 1967 and around 32 degrees of advance at 80 mm/Hg for 1968-1970. These two distributors can be run on any 30 PICT series Solex carburetor so long as allowances are made for the difference in vacuum advance.
_________________
Roads Scholar &
1957 Kombi low mileage 36 hp governor equipped M 178 Slow Drag Winner 2014, 2015, 2018

1965 hardtop Deluxe Microbus owned since 1990 M 620 factory 12 v 1500cc

1961 (October)Single Cab- Road Trip Workhorse

[tasb]

I would keep your R 2 distributor and get a 28 PICT restored by this guy who has a good reputation on this site:

https://www.thesamba.com/vw/classifieds/detail.php?id=2323655

You can then keep yours as a parts core.

You haven't stated the year of your VW so I'll ad that the ZV/PAU 4 R 2 was factory issued for model year 1961 types I and II only.
_________________
Roads Scholar &
1957 Kombi low mileage 36 hp governor equipped M 178 Slow Drag Winner 2014, 2015, 2018

1965 hardtop Deluxe Microbus owned since 1990 M 620 factory 12 v 1500cc

1961 (October)Single Cab- Road Trip Workhorse

[txasylum]

Yes, it is a 1961. I would like to keep the car as original as possible. I did spray a little starter fluid on the throttle shaft and it did rev up a bit. I tightened the nut on the shaft a little and that seemed to have helped a bit.
Also, on the vacuum I suck on the hose and the distributor does turn. But when I run the car and watch the marks with the timing light, it doesn't seem to advance much when I throttle it/rev it up quickly. If I disconnect the vacuum the car idles down.

Bob

[txasylum]

Thanks,

I emailed him about my carb and the ones he sells.

Bob

[txasylum]

I found a 30 PICT 1 in my carb pile (I only have three other carbs). I might put that on the car and see how it runs.

[KTPhil]

[txasylum]

When I suck on the vacuum line, the dizzy turns quite a bit. How much? I don't know how to measure that. I did put my tongue on the end of the line and it tends to slowly turn back to original position.

[txasylum]

The dizzy turns when I suck on vacuum line, but I don't think it holds. I put my tongue on the line to plug it off, but it slowly goes back to original position.