The Goose: Converting back to Dual Solex PDSIT-32/34

[xyzzy]

Before and after. Thanks Ken @ Busco for finding me a new pipe!





Getting closer.

[xyzzy]

Ok. The good news is, im 95% there.

We tore down the carbs, and found some issues.

2) The body pieces were warped -- so bad that you could see light between the surfaces with no gaskets. We ended up having to remove quite a bit of material with the hand file in order to get them to seal up properly with a gasket. 45 years of someone over tightening them I guess

2) The floats were way out of spec. 16mm left and 17mm right. Should be 12-14mm. We were unable to get the float into spec with the needle valve (stamped 1.5) and washer (1.5mm thick) in place. With the max bending of the float arm, and no needle valve washer, we could get to 14mm. This fixed the hesitation, but leaked tremendously sitting overnight. I replaced the 1.5mm washer with a 1.0mm washer, and there's still a hesitation. Tim @ Volkzbitz sent me a 0.5mm washer which will get me closer, but still not quite into the spec range.

So, I need to either shorten this needle valve, or get some more space between the top and the body. Maybe there's some thicker gasket material I can use and trace the existing gaskets onto and cut? I notice the data sheet for the walker kit online says the needle valves should be 1.2mm, but mine seem to come with 1.5mm ones -- maybe the 1.2mm are a bit shorter?

I've ordered both 1.5mm and 1.2mm NOS Solex Needle Valves from E-bay. Anyone have a good source for a thicker gasket stock I can trace and cut out from? That may be the easiest solution.....

[wcfvw69]

Since you've ordered new needle valve, why not try carefully removing that .3mm from the needle with a dremel? It would show you if it would cure that last remaining hesitation.

Most flaps have different thicknesses of fuel rated gasket material in sheets.

[xyzzy]

Yeah thats a good idea too. Got my 205J back thanks @wcfvw69! I'm at 12*ATDC now timed 28 max centrifugal. Runs great, good enough! Aeromech will be happy when I give him his distributor back :)

Just this pesky float level to get rid of the lean out off idle and I'm good to go. Then on to rebuilding the brake booster and getting a good undercoating on it.

https://www.youtube.com/watch?v=ElUlp_KCGQ0

[chachi]

those are nice elbows, who had those?

[xyzzy]

those are nice elbows, who had those?

German Supply. These were the best I could find and I looked long and hard.

[Amskeptic]

Update! ? !

[xyzzy]

I was going to wait until it was 100%, but in the spirit of an update:

Lesson 1:

If there are *ANY* air leaks, and they aren't fixed, then you will be in an endless rabbit hole of trying to compensate via carb adjustments. Suspect points of connection are manifolds, Brake Booster elbows, and the Brake Booster itself -- just because it holds vacuum doesn't mean its not producing an air leak when you apply the brakes.

Lesson 2:

Even though I was starting off with a pair of super nice original one owner carbs, the years of use has taken a toll on them. You need to fully disassemble the carburetors, and verify that every mating surface is flat. The metal on these are super soft, and over tightening them will warp the mating surfaces. Lining these up without gaskets you could see light passing through. We ended up having to remove a bit of material from most mating surfaces to get them within reasonable gasket range. Do not over tighten the carburetor screws!



Lesson 3:

Next, are you 100% that your float is within spec? It should be 12-14mm. Removing material from the carbs to get flush mating surfaces does not help this problem. I could not get my float into spec (currently at 14-14.5mm), which required cutting my own thick gasket which are about 2mm thick. I had the same issue as Ratwell wrote about on his dual carb page -- a 16-17mm float (with the popular Walker kit). I purchased a several aftermarket kits -- they're all crap. Start with the Walker.

The needle valves provided with the Walker kit don't help the situation either. The valve itself seats at a different height, and just replacing the valve with a correct NOS Solex valve increases the fuel in the bowl by 0.5-0.75mm. The washers that the Walker kit comes with is way too thick (1.5mm, and 1mm). I was able to get a 0.5mm washer from Tim @ Volkzbitz, and was able to find NOS Solex 1.2mm needle valve on E-Bay. Yes, they have the ball bearings, and I've heard the warnings. As Colin put it, don't abuse them and it will be fine.



If you're running your stock engine, you may be able to get away with the 14.5mm float.



The default combo from the walker rebuild kit doesn't come close to meeting float spec. The gaskets in the Walker kit are great quality but they are very thin. If you're float is not within spec, everything is going to seem like you're just one carb screw turn away from getting it right, and it will never happen.



Lesson 4:

Just because your idle jet solenoids are brand new and click does not mean they are functioning correctly. Of course the inverse is true, if they don't click, they certainly are not working. If you are unable to get through Colin's tuning procedue because your engine wont run when you disconnect your central idle circuit without turning out the carb mixture screws out a ridiculous amount, it means one of the items above is not correct!. Make sure you have no air leaks, and make sure your float is correct.

If you find yourself connecting and reconnecting the idle jet solenoids frequently trying to get through the procedure, and you notice that suddenly your engine is idling weird, pull your solenoids, blow some air through them, and try again. Sometimes just cycling the power to idle jet solenoids gives them the kick in the butt that may fix it.

As for where I'm at currently:

1) My timing is now about perfect thanks to the awesome and correct one year only 205J distributor (thanks Bill!). 28* max advance hoses off, 7.5*BTDC without retard, 11*ATDC hoses on. Previously I was getting a quite exceptional retard, and Bill has fixed that by adjusting the stop post.

2) My brake booster is still disconnected. I just haven't had time yet to get it repaired. While it held vacuum, when you applied the brake it it created an air leak. Apparently my brake booster is original and never worked since I owned it, and I just assumed that's how the bus stopped! Looking forward to getting that fixed.

3) My float is 14.5mm left, 14mm right. This is just enough out of spec, that with my 2L engine, I'm getting slightly lean accelerating (mid-high 14s), and the ever so slightest hesitation when its cold off idle hitting the transition ports. I'm jetted now 135 mains which seems to be the sweet spot for power and economy. I can get my float to 13.5mm by removing the needle valve washer, but with the hill I park on it floods out overnight. I still need to get another 1-2mm of fuel in the bowl -- I'm afraid to try bending the float tabs and braking them. The floats that come with aftermarket kits are garbage. The point of contact on the float arms which hit the needle valve are very close to the end where the metal post goes through -- there is actually a very small little notch/indentation on the original Solex float of where this point of contact in. Bending these is a recipe for disaster.

4) My fast idle on the chokes isn't working anymore -- it worked great when Colin was here, and presumably with the half dozen plus times I've taken these carbs off and put them back on, I've got the adjustment off. Working on this after I figure out the float.



As Satchmo stated in his thread, there is a huge difference when these carbs are running right -- even if they are "close" it's nothing compared to when they are running right. The exhaust note at cruise is nothing short of amazing. Acceleration is smooth, and there is tons of power. The difference between my baby Weber setup and now literally is like driving an entirely different car. The power, slow speed drive-ability, and cold starts are game changers.

Lastly, there is no way I would ever have been able to do any of this without the VW community. Special thanks to Colin, Robbie, Aeromech, Telford, Bill, Tim @ Volkzbitz, Satchmo, and everyone else -- the VW community is truly a national treasure. I knew more or less nothing about this engine before starting with my first Airschooled and Itinerant appointments.

If you're considering booking time with Colin and haven't, you're doing yourself and your bus a major disservice by not booking time with them.

Aloha.

[xyzzy]

Just noticed in those previous pictures of my carb that my fast idle link nuts are much further from the top than they are now -- so maybe that's the solution to my fast idle choke not working now.

I also need to find where I can get the fresh air hose that goes from the air cleaner intake which curves around to the bracket above the battery. Anyone have any ideas? I have my original one but its so rotted that it's unusable.

[satchmo]

Sounds like you're the expert now. Excellent write up.

Satchmo

[Amskeptic]

This is why you do not have fast idles. I can see it from here . . .

Look at those fast idle links sprouting up so high I can see them from Illinois.

The upper edges of the threaded links should be at about 4 threads above the upper lock nuts.
ColinInIllinois
(I won't be able to see them from Indiana)

[xyzzy]

This is why you do not have fast idles. I can see it from here . . .

Look at those fast idle links sprouting up so high I can see them from Illinois.

The upper edges of the threaded links should be at about 4 threads above the upper lock nuts.

Hah! Ok, so those previous photos were after our re-rebuild of the carbs... this is where they actually were today, which wasnt kicking of fast idle:



I've moved them up to the 4 threads above the top nut and we'll see how it lights off tomorrow.

[Jivermo]

I’m a fuel injection bay owner, but I sure have enjoyed reading this. Nice work, and photos! Thanks.

[xyzzy]

I’m a fuel injection bay owner, but I sure have enjoyed reading this. Nice work, and photos! Thanks.

Thanks! It's been quite the education.

@Amskeptic -- fast idle fixed :) May need to do another half turn up -- whats the ideal RPM speed on the fast idle on a cold start?

[Amskeptic]

whats the ideal RPM speed on the fast idle on a cold start?

No such thing, because of ranging environmental variables, but stone cold freezing first light-off 1,300-1,500, first blip should knock it down to 1,200 ish, there is a specification in the Bentley that requires removing the carbs to adjust.
Colin