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vwpieces
Samba Member
Joined: March 23, 2005
Posts: 360
Location: UpHill BothWays, PA
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 Posted: Fri May 10, 2019 5:35 pm Post subject: Re: 34 PDSIT SOLEX CB Performance |
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| Alstrup wrote: |
First you need to make a 60 to 80 mm "stack" for the carbs. That helps some. |
Not sure what or where the "stack" is or should go 
Raise carbs to mimic a longer intake?
Velocity stack on top of carb?
Or just an extension to the air cleaners to raise them up a bit?
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68 BUS
83 JETTA TURBO DIESEL
83 2dr JETTA 16V
81 Turbo Diesel Jabbit |
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vwpieces
Samba Member
Joined: March 23, 2005
Posts: 360
Location: UpHill BothWays, PA
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| Posted: Fri May 10, 2019 9:25 am Post subject: Re: 34 PDSIT SOLEX CB Performance |
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| Alstrup wrote: |
Yeah, something else is wrong.
First you need to make a 60 to 80 mm "stack" for the carbs. That helps some. Are these carbs with- or without WOT enrichment?
I would check the float height against the discharge hole in the main circuit too.
The 32 mm PDSIT´s don´t like more than 26 mm venturies, and the older version that was born w. 23 mm venturies have a limit around 25mm. Even when I push these carbs to the limit, (pulling 80+ hp through them) with 26 mm venturies I am around 160 mains and 150ish main air. Then the AFR curve is nice and even.
IMO a no frills 1600 sgl port should have no more than 24 mm venturies unless the heads have been massaged to flow really well. Then we can talk 25-26 mm.
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Thank You Alstrup, you got me feeling better with where I am at on these "32mm" carbs and pretty stock 1600 SP.
These are the 32mm throttle plate PDSI Brazilian carbs, I think they were stock on something like Puma GT. This set in the classifieds is similar to what I have. My carbs are Brazil and linkage is same, air cleaners same.
https://www.thesamba.com/vw/classifieds/detail.php?id=2112904
Been trying to work back up in main air @ 125 now with the 24mm venturis, 165 main Jet, 50 idle.
Decel is rich @ 12AFR. Runs mostly 13.5 ish through accel and holding WOT through 3rd leans to 15ish AFR
28mm Vents is absolutely a NO GO. I can get it running fine but holding throttle to accelerate engine, it will just run out of fuel till it dies if I hold it open that long.
26mm pretty much do the same but it can run a little better and sort of driveable. Still falls on its face with hard acceleration, going way lean.
24mm with current jetting runs good (compared to all else so far) but I have it too rich down low to help compensate for the WOT that still leans out but now stabilizes to about 15 AFR and 125 Airs, 165 main. With 115 airs I can get it to stabilize @ about 14.2AFR WOT, 165 mains.
I would like to get a pair of 23mm Venturis and I think I can get the WOT straight, I know I'm close now. Thanks for the help and getting my head straight. I had 2 days Trying to get the 28mm venturis working. To the point I was throwing parts at it, Coil, Spare German SVDA, Fuel pump.... and still thinking bad thoughts like having cam gear installed wrong, or off a tooth on crank. Cause I know my issues are air flow related to getting the carbs functioning properly.
Float height is 15mm. Stock fuel pump is the 40HP style on my bus, fuel pressure on this pump is 3.25psi. I have another pump setup for 2psi and have tried both with same result, no change. Both pumps are recent rebuilds and I have the factory tools to set them up. New inline filter under tank. Will double check flow for sanity purposes but doubt its an issue. Very Early 68 bus here, like first 50K production, no fire wall at gas tank and the vent tube is just the looped pipe to air venting (no charcoal can). Will also check vent pipe.
A month ago I had a 1600DP, 34 PICT3, SVDA, in it that ran great in this bus, but leaked oil. Pulled for a reseal and freshening up. No fuel delivery issues. Meanwhile built this 1600 SP from mostly new or very low mileage, spare parts. Cam and lifter are matched and were New.
Been using some 80mm long Silicone couplings to raise my Sync tool over the air cleaner top mounted screw. Will try to integrate them into the air cleaner mounting as a "stack". Not 100% sure but I do not think there is WOT enrichment on these. No other tubes at the choke flap area besides the accel pump nozzle. Will get some pics next time they are off and apart. Will be soon, I'm sure.
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68 BUS
83 JETTA TURBO DIESEL
83 2dr JETTA 16V
81 Turbo Diesel Jabbit |
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Alstrup
Samba Member
Joined: July 12, 2007
Posts: 7825
Location: Videbaek Denmark
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| Posted: Fri May 10, 2019 1:56 am Post subject: Re: 34 PDSIT SOLEX CB Performance |
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Yeah, something else is wrong.
First you need to make a 60 to 80 mm "stack" for the carbs. That helps some. Are these carbs with- or without WOT enrichment?
I would check the float height against the discharge hole in the main circuit too.
The 32 mm PDSIT´s don´t like more than 26 mm venturies, and the older version that was born w. 23 mm venturies have a limit around 25mm. Even when I push these carbs to the limit, (pulling 80+ hp through them) with 26 mm venturies I am around 160 mains and 150ish main air. Then the AFR curve is nice and even.
The early 34 mm bus 34´s with 28-29 mm venturi are usually around 160-170 main and 160-170 main air. That´s for about 94 - 100 hp.
IMO a no frills 1600 sgl port should have no more than 24 mm venturies unless the heads have been massaged to flow really well. Then we can talk 25-26 mm. |
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Slow 1200
Samba Member
Joined: July 02, 2004
Posts: 2127
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| Posted: Fri May 10, 2019 1:02 am Post subject: Re: 34 PDSIT SOLEX CB Performance |
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| are you sure you don't have a fuel restriction issue (pump, tank, breather?) |
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vwpieces
Samba Member
Joined: March 23, 2005
Posts: 360
Location: UpHill BothWays, PA
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| Posted: Thu May 09, 2019 3:44 pm Post subject: Re: 34 PDSIT SOLEX CB Performance |
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Have the 1600 Single port in the 68 bus and have been trying to get it dialed in.
Gave up on the 28mm Venturis as they just leaned out the top end till it would just shut off.
Went to 24mm vents that these carbs originally had installed and finally started to get a driveable bus.
Just for the heck of it, today, I tried the 26mm venturis. Kinda driveable but still gets lean on top end WOT and looses power.
So back to the 24mm Venturis... and still getting Somewhat lean top end WOT even with 165 main jets and too rich up to WOT. Have the 115 Air jets in too, and they are the smallest I have. 110 will be here Monday.
This engine is liking the smaller venturis and 24 is the smallest I have.
Have a line on a pair of 23mm for cheap but not in USA.
Anyone have 23mm pair they would like to trade for 26mm or the CB 28mm venturis I have?
May consider the 22mm if anyine wants 26 or 28's
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83 JETTA TURBO DIESEL
83 2dr JETTA 16V
81 Turbo Diesel Jabbit |
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daos
Samba Member
Joined: January 01, 2017
Posts: 312
Location: Stockholm, SWE
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| Posted: Mon May 06, 2019 8:07 am Post subject: Re: 34 PDSIT SOLEX CB Performance |
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| or i just stuff a nice bratwurst in each side and call it done. |
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FreeBug
Samba Member
Joined: March 12, 2012
Posts: 4277
Location: deepest, darkest Switzerland
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| Posted: Mon May 06, 2019 8:03 am Post subject: Re: 34 PDSIT SOLEX CB Performance |
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| daos wrote: |
maybe i should try syncing with garlic & butter instead?
garlic on the left, butter on the right, or an equal mix? |
Nah, it's got to be the same thing on both sides. The best thing for it is frog's legs, they come in matching pairs. |
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daos
Samba Member
Joined: January 01, 2017
Posts: 312
Location: Stockholm, SWE
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| Posted: Mon May 06, 2019 7:43 am Post subject: Re: 34 PDSIT SOLEX CB Performance |
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maybe i should try syncing with garlic & butter instead?
garlic on the left, butter on the right, or an equal mix? |
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FreeBug
Samba Member
Joined: March 12, 2012
Posts: 4277
Location: deepest, darkest Switzerland
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| Posted: Mon May 06, 2019 7:35 am Post subject: Re: 34 PDSIT SOLEX CB Performance |
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| daos wrote: |
| good stuff, thanks. snail is clearly the way to go, kind of expensive though (in europe). thanks for all the input! |
They eat snails in Europe, and, yes, they are expensive...
It's all in the garlic and butter.. |
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daos
Samba Member
Joined: January 01, 2017
Posts: 312
Location: Stockholm, SWE
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| Posted: Sun May 05, 2019 11:27 pm Post subject: Re: 34 PDSIT SOLEX CB Performance |
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| good stuff, thanks. snail is clearly the way to go, kind of expensive though (in europe). thanks for all the input! |
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daos
Samba Member
Joined: January 01, 2017
Posts: 312
Location: Stockholm, SWE
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| Posted: Sun May 05, 2019 11:27 pm Post subject: Re: 34 PDSIT SOLEX CB Performance |
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| good stuff, thanks. snail is clearly the way to go, kind of expensive though (in europe). thanks for all the input! |
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FreeBug
Samba Member
Joined: March 12, 2012
Posts: 4277
Location: deepest, darkest Switzerland
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| Posted: Sun May 05, 2019 3:52 pm Post subject: Re: 34 PDSIT SOLEX CB Performance |
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| daos wrote: |
spot on and good advice. i arrived at the same conclusion - choke related.
so yeah, i took both carbs off again  and went through them with specific focus on the chokes and indeed, one of the choke link rods was adjusted so the throttle butterfly was halfway open.
correct setting for 32's is 0.6mm according to an old manual i picked up a while ago (Volkswagen 1600 1965-73 Autobook by Kenneth Ball), that's what they both have now and guess what? yes, it idles very happily at whatever speed i set it at. a bit of fiddling with linkages and throttle cable tension helped too.
also tried syncing by ear with a piece of 10mm plastic tube which was fun, first time i've tried that. two things are immediately obvious:
- the tone of the carbs is slightly different so despite the fact everything should be identical on the inside it clearly isn't, at least not down to the last molecule
- the amount of air they suck in is clearly audible and also not identical, left carb is sucking more air. hearing that isn't so hard, trying to adjust it out is with only two parameters, idle screw and volume screw. will give it another shot this week, though it's running pretty well right now. not perfect but it's definitely progress.
- bonus thing - you can hear the valves/intake pulses etc through the carb, almost like being inside the engine, pretty cool. recommend trying it just for that. |
That 0.6mm figure is the throttle opening at idle starting point. The 2.1 mm i quoted is for the proceedure i described. It holds the throttle open the correct amount during the choke operation. It's important.
Do all your idle tuning with the linkages disconnected. Do that last, make sure the idle doesn't change when you hook up the linkage, and check for balanced flow with the accelerator cable pulled enough to get the engine to about 1300 rpm then check that flow is equal. Get a snail flowmeter!
Without a snail, i think you are losing your time with listening to hoses. Get a snail, if you have more than 1 carb, it's indispensable.
Hope this helps. |
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daos
Samba Member
Joined: January 01, 2017
Posts: 312
Location: Stockholm, SWE
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| Posted: Sun May 05, 2019 12:52 pm Post subject: Re: 34 PDSIT SOLEX CB Performance |
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spot on and good advice. i arrived at the same conclusion - choke related.
so yeah, i took both carbs off again and went through them with specific focus on the chokes and indeed, one of the choke link rods was adjusted so the throttle butterfly was halfway open.
correct setting for 32's is 0.6mm according to an old manual i picked up a while ago (Volkswagen 1600 1965-73 Autobook by Kenneth Ball), that's what they both have now and guess what? yes, it idles very happily at whatever speed i set it at. a bit of fiddling with linkages and throttle cable tension helped too.
also tried syncing by ear with a piece of 10mm plastic tube which was fun, first time i've tried that. two things are immediately obvious:
- the tone of the carbs is slightly different so despite the fact everything should be identical on the inside it clearly isn't, at least not down to the last molecule
- the amount of air they suck in is clearly audible and also not identical, left carb is sucking more air. hearing that isn't so hard, trying to adjust it out is with only two parameters, idle screw and volume screw. will give it another shot this week, though it's running pretty well right now. not perfect but it's definitely progress.
- bonus thing - you can hear the valves/intake pulses etc through the carb, almost like being inside the engine, pretty cool. recommend trying it just for that. |
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FreeBug
Samba Member
Joined: March 12, 2012
Posts: 4277
Location: deepest, darkest Switzerland
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| Posted: Sun May 05, 2019 6:15 am Post subject: Re: 34 PDSIT SOLEX CB Performance |
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| daos wrote: |
these are older 32pdsits, much more basic then the 32-34 bus type. there is just one vacuum port - for the distributor - and it’s blocked as i’m running a 009.
idle screw adjusts the throttle butterfly. these are both all the way out. i’m guessing the only way to adjust idle now is to reduce the butterfly gap altgough it’s pretty minimal. maybe be the chokes? but it’s idling fast even when warmed up. otherwise it drives well. |
Ok,I better understand now, and I think I know what your problem might be: there is a specific set-up for those carbs, dealing with the rod linking the butterflies to the chokes.
-you need to close the throttle till the progression ports disappear.
-you need to open the throttle, then close the choke manually, then let go of the throttle. There will now be a gap between the throttle stop and the air adjustment screw. You need to adjust this intermediary linkage so that that gap is 2.1 mm (IIRC, and 2.3 mm for the type 4? but look it up). That will hold your idles open when the choke is engaged, and let them close when it isn't.
-hope that helps. |
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daos
Samba Member
Joined: January 01, 2017
Posts: 312
Location: Stockholm, SWE
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| Posted: Sun May 05, 2019 4:07 am Post subject: Re: 34 PDSIT SOLEX CB Performance |
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these are older 32pdsits, much more basic then the 32-34 bus type. there is just one vacuum port - for the distributor - and it’s blocked as i’m running a 009.
idle screw adjusts the throttle butterfly. these are both all the way out. i’m guessing the only way to adjust idle now is to reduce the butterfly gap altgough it’s pretty minimal. maybe be the chokes? but it’s idling fast even when warmed up. otherwise it drives well. |
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FreeBug
Samba Member
Joined: March 12, 2012
Posts: 4277
Location: deepest, darkest Switzerland
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| Posted: Sun May 05, 2019 2:10 am Post subject: Re: 34 PDSIT SOLEX CB Performance |
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| daos wrote: |
always good to try, imagine jets are pretty demanding to make. clockmaker level accuracy.
rebuilt my pdsit-3 with a spare body to make a matching pair. cleaned everything (again!), upgraded venturis to 23mm, main jets to 135, idle 50 and air 150, and increased the accelerator pump travel.
runs very well now, no more hot/cold side. free revving, no flat spot. just one issue though and that is a very high idle speed - around 1300-1400 rpm even with the idle screws all the way out.
i may need to adjust the throttle butterfly gap, currently at 0.25mm, evidently too much. linkage is also a little sloppy but it's old with basically no adjustment left. only thing i can do is replace it at some point but the idle is high even with it disconnected. will also check throttle cable tension just in case. also still need to sync but really need to adress the high idle first.
the overall result is positive. |
Funny you should say that, i have borrowed reamers from a watchmaker (there's a lot of them around here), but that was for fuel jets. Air jets are quite a bit bigger than those, and I think it's less crucial to get them perfect. But still, they are pretty "artisanal"...
That fast idle is something which must be pretty simple to figure out. You should do the synch at the same time (synched, get it?) as you set the idle. It can be tricky to get the idle speed you where want with equal airflow side-to-side.
When you say "idle screws", do you mean butterfly or fuel? You need to have the butterfly as low as possible, to neither engage the progression nor the vacuum ports at idle.
Remember, if your vacuum port is exposed at idle, the extra advance will raise the rpms. And once the rpm go up, the centrifugal might kick in, too.
You need to equalize flow side-to-side, then set Best Idle, then see where rpm are, lather, rinse, repeat, till you have it as you want.
Remember, 1500 vents on a 1600 will be just a little small, but it should still be able to tune around. Do you have a Snail, a wideband O2 sensor, and a strobe light? If so, you can solve this easily and quickly. Without, you have to be really good at tuning by ear, plugs, etc. Really good. |
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daos
Samba Member
Joined: January 01, 2017
Posts: 312
Location: Stockholm, SWE
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| Posted: Sat May 04, 2019 2:07 pm Post subject: Re: 34 PDSIT SOLEX CB Performance |
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always good to try, imagine jets are pretty demanding to make. clockmaker level accuracy.
rebuilt my pdsit-3 with a spare body to make a matching pair. cleaned everything (again!), upgraded venturis to 23mm, main jets to 135, idle 50 and air 150, and increased the accelerator pump travel.
runs very well now, no more hot/cold side. free revving, no flat spot. just one issue though and that is a very high idle speed - around 1300-1400 rpm even with the idle screws all the way out.
i may need to adjust the throttle butterfly gap, currently at 0.25mm, evidently too much. linkage is also a little sloppy but it's old with basically no adjustment left. only thing i can do is replace it at some point but the idle is high even with it disconnected. will also check throttle cable tension just in case. also still need to sync but really need to adress the high idle first.
the overall result is positive. |
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FreeBug
Samba Member
Joined: March 12, 2012
Posts: 4277
Location: deepest, darkest Switzerland
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| Posted: Tue Apr 30, 2019 10:05 am Post subject: Re: 34 PDSIT SOLEX CB Performance |
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| daos wrote: |
found this supplier on ebay with a good range of solex jets:
https://www.ebay.co.uk/usr/carb.deals?_trksid=p2057872.m2749.l2754
bus carbs would be nice. will definitely update once the jets arrive and i start experimenting. just to clarify - this car is a bona fide back from the dead vehicle, after 20 odd years languishing in the woods of northern sweden.
here's a shot from yesterday's carb workshop
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Those are the early type, from the 1500S, they don't have a choke override membrane yet. The idle fuel adjustment has a coarser thread, too
Thanks for that link! I'd given up looking for them, and started making my own...and not very well  . |
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vwpieces
Samba Member
Joined: March 23, 2005
Posts: 360
Location: UpHill BothWays, PA
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| Posted: Mon Apr 29, 2019 3:06 pm Post subject: Re: 34 PDSIT SOLEX CB Performance |
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Just rebuilt a 1600 Single Port
Web cam 86 grind and their cam followers
Web cam single valve springs
8.1CR
Some match porting in heads and aluminum intakes hogged out Intakes have MB on castings, no idea how or where they were from. Studs were too wide for the Solex, so some creative drilling for helicoils brought the studs closer to fit these carbs. Also running the bakelite spacers.
VW 034 SVDA with old pertronix, no vacuum at idle...
Timing @ 28* vac line disconnected/plugged. Pulls to 44* when line connected on accel.
Heater boxes and an old Ernst stock exhaust, welded on flanges and gaskets. All ports cleaned up for flow. And home made damper pipe that is larger ID and O2 bung. Made tail pipe from an old industrial engine J-Tube. Sounds good.
I have 2 sets of the PDSI carbs, both appear to be older aftermarket sets. One set has the pressed in air correction jets and had 26mm venturis. Chose NOT to use this set because of the fixed air correction jets.
Now on engine are the pair of H32/34 PDSI 2-3 actual left and right carbs.
Have the CB 28mm venturis
Some stock Brazilian car air filters with VW and 040 part number on top with K&N filters.
Current jetting to get into ball park and running decent on engine stand.
55 idle
115 air correction
160 mains
Stock rebuilt 40HP type fuel pump with 2 PSI
Float level about 12mm
Tried to follow some of the jetting others have used but this engine wasn't having it.
I am close to what this set originally had installed with 24mm venturis, 52.5 idle solenoids, 115 air correction and 155 mains.
Not sure how you guys are running 180 ish air correction jets as My engine would not even rev with 130 and higher. Ended up going down with better results.
Now my question is about throttle plate positioning and balance tube...
With balance tube crimped off and setting up with old Uni-Syn metal synchronizer I get it equal at throttle plates @ 900rpm. Choke lever arms are not bound up. Now when I un-crimp the balance tube I drop rpm to about 600ish rpm.
Seems odd and making me question things.
Should I use the timing to gain back the rpm, keeping throttle plates as set with balance tube crimped?
would drilling holes in throttle plates help here?
I have an LM2 wideband hooked up and will also use it to get it dialed in once installed in my 68 bus.
_________________
68 BUS
83 JETTA TURBO DIESEL
83 2dr JETTA 16V
81 Turbo Diesel Jabbit |
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daos
Samba Member
Joined: January 01, 2017
Posts: 312
Location: Stockholm, SWE
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| Posted: Sun Apr 28, 2019 2:05 pm Post subject: Re: 34 PDSIT SOLEX CB Performance |
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found this supplier on ebay with a good range of solex jets:
https://www.ebay.co.uk/usr/carb.deals?_trksid=p2057872.m2749.l2754
bus carbs would be nice. will definitely update once the jets arrive and i start experimenting. just to clarify - this car is a bona fide back from the dead vehicle, after 20 odd years languishing in the woods of northern sweden.
here's a shot from yesterday's carb workshop
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