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

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

Post by Amskeptic » Wed Jul 18, 2018 8:00 am

Latest post of the previous page:

xyzzy wrote:
Tue Jul 17, 2018 8:35 am
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
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 86,570 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,113 miles

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

Post by xyzzy » Mon Jul 23, 2018 7:49 am

In the spirit of updates:

Float Plan

I managed to find some original NOS Solex PDSIT gaskets -- I'm curious as to the thickness of the originals. They're in the mail, we'll find out soon. I'm still at 14-14.5mm floats and am running a tad lean with a slight off-idle hesitation. I've also ordered another set of NOS 1.2mm needle valves, and another set of aftermarket 7gram floats that appear to have a bendable bracket. Will try to get the float into the 12-14mm spec when the parts arrive.

Other items

1. Have brake booster rebuilt. It's currently disconnected.

2. My clutch pedal has stopped returning all the way -- have to pull the last inch or so out with my toe! If I just side slip the clutch (while in neutral of course) it does return all the way making that nice thumping sound when the rubber grommet makes contact. Maybe just need to grease components?

3. Surface rust treatment in the rear quarter vents. One year at the beach is taking its toll. Going to just spray with an encapsulator since its very hard to reach in there.

4. Remove all dealer installed AC components. Big-fugly-plastic-under-dash-component, hoses, and under-carriage components which, as Colin puts it, really hurts the animals after you run over them.

5. Apply rubberized under-coating

6. Install some Dakota Digital gauges (CHT, Oil Temp, Oil Pressure?)

Also installed some mudflaps!

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

Post by xyzzy » Mon Jul 23, 2018 11:29 am

In case anyone happens across this thread searching for carb info, I came across some great illustration for these carbs.

Image

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

Post by xyzzy » Fri Jul 27, 2018 3:45 pm

I was *finally* able to get my float into spec, and was able to get 12-12.5mm. It took a combination of:

1) A different float from an old NOS Solex kit. The float is still the 7gram, doesnt say Solex on it, and is a slightly different shape. I had to open up the hinge on the floats so the bar rotates freely inside of it. Maybe my original ones had been bent at some point previously.. Ratwell seemed to have the exact same problem with a 16-17mm float -- who knows.

2) NOS Solex 1.2mm needle valves. The needle valves in the walker kit really are poor quality. I have 8 new Walker valves, 3 of them stick, one came clogged, and 4 seem to be somewhat normal. The NOS Solex 1.2mm's all work perfectly and dont stick. I used a 0.5mm washer on the valve.

3) I was able to use the nice thinner Walker gaskets instead of my 2mm hand cut one with the new float and Solex needle valves

4) Slight outward bending of the float holder spacer thing to accommodate the new floats.

No more big hesitations, lots of power. Exhaust note is sublime.

I drove out to Jbugs in Oceanside to pick up two new idle jet solenoids since the one on my right carb needs to be power cycled several times everytime I take the carb off and put it back on for some reason. It drove amazingly -- 30 mile roundtrip up and down hills 3rd and 4th gear on the back roads.

Laser temp gauge was showing 255-260 top of the engine and 247 on the taco plate -- which sounds awfully hot. Bus seemed to run fine, and the dip-stick was only warm to the touch -- no problem grabbing and holding it. I pulled the dip stick, and shot the end of it with oil on it and it read 145. Left valve cover 260, right valve cover 215... Not trusting the laser temp gauge for now.

I will do the tuning procedure and hook up the AFM this weekend and see where things stand.

This weekend I am going to tackle the surface rust inside the rear quarter panel vents that's accumulated in the last year of living at the beach. Will take some photos.

THANKS FOR EVERYONES HELP!
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Re: The Goose: Converting back to Dual Solex PDSIT-32/34

Post by xyzzy » Sun Jul 29, 2018 7:06 pm

Living at the beach has taken its toll. Had some nasty surface rust in both quarter vents after just a year. None of this was here a year ago. It's a real tough spot to get to.

Image

Taped it off, used a degreaser and some compressed air. Treated it with three coats of Eastwood rust encapsulator (in gray). Got it into there as best I could without making too much of a mess. Ended up with some drips, but seems like par for the course for how unaccessible these vents are.

Image

Finished it off with two coats of L90D in a rattle can and a clear coat

Image
Image

Have to say it's way better than before. Will see how this holds up.
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Re: The Goose: Converting back to Dual Solex PDSIT-32/34

Post by Amskeptic » Thu Aug 02, 2018 7:54 am

xyzzy wrote:
Sun Jul 29, 2018 7:06 pm
Living at the beach has taken its toll.
Have to say it's way better than before. Will see how this holds up.
Yes! Eye for detail!
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 86,570 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,113 miles

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

Post by xyzzy » Thu Aug 09, 2018 8:30 am

Well I still have an off-idle, low RPM accelerating lean condition, but otherwise bus starts wonderfully, and runs great at full/brisk throttle and light cruise. I'm jetted with 135 mains and 140 air bleeds. My AFM readings seems within spec, if not a tad rich:

1) Idle 12.8-13% at 1k RPMs
2) 35mph 3rd gear 12.8-13.0%
3) 40mph 4th gear cruise 12.6-12.8%
4) 55mph 4th gear light cruise 12.8-13%

Doing the tuning procedure, with retard disconnected, and central idle solenoid disconnected, I get a 650RPM idle. Pulling either solenoid and the engine dies. Otherwise the rest of the tuning procedure seems to go well.

Heavier throttle acceleration goes right through the lean hesitation where you barely even notice it. Trying to cruise at a lighter-mid-throttle and you can feel it and AFM readings shoot up to 14.5-15.5... My MPG is 13-16 over the last 500 miles, at several different mixture setting attempts, which is definitely not right.

Current thoughts:

1) These aftermarket solenoids just seem suspect to me. I've got a few different sets, jbugs, busdepot, and the "old" ones that came with my bus but aren't original. They are the G55s. I have the collars and rubber inserts. I've found a set of NOS Pierburg VW G55 solenoids which arrived this morning that I will try next. I also managed to find a set of fixed Solex idle jets (non solenoid) in 55 and 60 which I was going to try even though this may result in dieseling at shutdown, I figure it will be a good data point.

2) The PDSIT tuning procedure calls for 1/4 turn passed contact on the stop screws. This is where I'm at now. Bentley says stick a feeler gauge up there (0.10mm i think?) to check the gap between throttle plate and carb body. Perhaps the throttle plate at 1/4 turn on the stop screws is just a tad too open on my carbs, and during off-idle acceleration is delivering a tad too much air activating the transfer ports to soon, and I've masked the previous range with carb/idle mixture settings? Maybe I should pull the carbs and check that throttle plate gap next?

3) My engine seems hot. The left valve cover is about 240 degrees, and the right is 210. Top of the engine 240, taco plate 220. I don't have gauges yet and am using a laser temp gun. I do remember that with my baby weber setup, after a 100 mile highway run I'd see 250 top of the engine, but never shot the valve covers or anything else so I'm not sure maybe this is just normal. I dont have any oil lights coming on, or any loss of power so maybe this is just a false concern.

My carb settings ended up at ~2.75 turns left, ~2.5 turns right, central idle 1.1 turn.
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Encinitas, California USA

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

Post by tommu » Thu Aug 09, 2018 12:51 pm

I am really enjoying reading your journey here. Sounds to me like you are mastering the tune of your Bus now. It's inspiring.

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

Post by xyzzy » Thu Aug 09, 2018 4:28 pm

tommu wrote:
Thu Aug 09, 2018 12:51 pm
I am really enjoying reading your journey here. Sounds to me like you are mastering the tune of your Bus now. It's inspiring.
Glad someone is enjoying it -- I'm pulling my hair out.

Ok. Solenoids. I'm assuming this is factual:

Image

It appears that the solenoids I've received from Jbugs and Busdepot are both Borsol #058129413D. Interestingly enough, I've seen this part number advertised online and on forums as both VW 111 129 413A and 111 129 413B, and mainly advertised for the 30 PICT 1 and PICT 2 carbs. Of course the 413A is 6 volts and the 413B is 12 volts. I have a total of 6 of these aftermarket solenoids (new) with the black plastic tabs protectors. All of them "click", 2 or them don't open the valves at all even though they click, 1 of them doesnt close. The "old" ones I have without the black plastic tab protectors both click, but one of them is obstructed. The size of the orifices on the sides of the solenoids seems to be two different sizes even though they are allegedly all G55s.

I'll do a detailed photo comparison of them tonight with the NOS Pierburgs and the "old" ones I have.
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Re: The Goose: Converting back to Dual Solex PDSIT-32/34

Post by xyzzy » Sat Aug 11, 2018 10:31 am

Ok. So the Solenoids are indeed suspect. Here's the deal:

Image

Jbugs solenoid on the left --just eyeballing the orifice at the output end its not a 55 as advertised. I think this is actually 6 volts, but more on that later.

Next Up, these I got from Busdepot and they were in Borsol boxes. They are stamped 55 on the nut and 12V on the plastic tabs. This is what I was running previously.

The third from the left are my "original" ones -- I'm not about to claim these are original from when the bus was purchased new, but it wouldn't surprise me . They are original in the since I never changed them from the original untouched carbs. One of these worked, one was clogged. I had been soaking them in carb cleaner for a week.

The last are the "NOS Pierburg" 12 VOLT VW 113 129 414

Image
Image
Image

Image

Comparing the jet input orifice from the Pierburg to the Borsol, it's clearly considerably bigger:

Image

My "original" old ones are the most identical match to the Pierburg set, which is interesting. Going to try these now and report back
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Re: The Goose: Converting back to Dual Solex PDSIT-32/34

Post by satchmo » Sat Aug 11, 2018 1:34 pm

I doubt the overall length of the solenoid makes any difference. But the distance of the side ports from the shoulder (at the end of the threads or just a little beyond) might. The distance of the side port from the shoulder on the solenoids from Bus Depot and your old one look pretty similar. The JBugs one is just a hair longer. But the Pierburg one is quite different from the other three, From the photograph, it also looks like the diameter on the Pierburg solenoid is greater than the other three.

Let us know what you discover.

Satchmo
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First, by reflection, which is noblest;
second, by immitation, which is easiest;
and third, by experience, which is bitterest. -Confucius

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

Post by xyzzy » Sat Aug 11, 2018 8:29 pm

The input orifice on the Pierburg is significantly bigger, and the output orifices (the ones on the side of the shaft) were visibly bigger as well. The VW part number is not listed on the solenoid part list I posted above (which I'm assuming is ground-truth), so who knows what it was originally designed for.

Swapped in the Pierburg solenoids and It was immediately clear they were producing far more fuel in the idle passage -- super rich, and so much so I had to turn down a full turn on each carb to get it to just barely idle. Went through the tuning procedure anyways, from the carb mixture forward, and was able to complete every step fine -- including pulling individual solenoids and balancing. However, since these solenoid jets were providing much more fuel, I ended up having to crank down the mixture screws on each carb -- we're talking ending up at less than 1 turn on each carb! Wild.

After the tuning procedure, went for a drive, and now I've swapped the off-idle lean for an off-idle flood!! However, bus ran amazing everywhere else in the power band, including idle. It's really amazing just how robust this PDSIT system is.

So, now I'm entirely convinced that my previous off-idle hesitation is solenoid or throttle plate related. In summary:

The jbugs solenoids dont sit right in the carb bodies and I'm sure they are not designed to be used with the collars and rubber grommets -- I'm not even convinced they are actually 12 volts. I'll disassemble one and take some pictures soon. You can even see the output orifice in the shaft in the picture above -- it doesn't open or close properly. It's just a really shitty part, and I don't think they're made for these carbs. I would be shocked if anyone is actually running those in a PDSIT 32-34 setup successfully.

The Bus Depot / Borsol solenoid just feels cheap. It doesn't seat into the carb body the same was as my original one, or the Pierburg. The shoulder is too big, the "spacing" for the collar is too big, and I'm wondering if the output orifices dont line up with the passageway correctly when tightened.

The Pierburg and my "original" solenoid both feel considerably different when you're holding them -- much heavier, and it's clearly made better. They both have the exact same spacing for the collars, and they both seat into the carb body perfectly without munging the collar rubber grommets. Other than the Pierburg one I have being the wrong part number and clearly a bigger jet, it's clearly the "same part" as my original.

I have a set of fixed Solex idle jets (55s and a set of 60s too) that I'm going to try tomorrow and eliminate the solenoid entirely. In the meantime I've managed to now get my second original Solenoid passage cleared after soaking in carb cleaner. Ultimately I think that will be my best bet.

More to come.
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Re: The Goose: Converting back to Dual Solex PDSIT-32/34

Post by xyzzy » Sun Aug 12, 2018 9:10 am

Ok. So I installed my "original" solenoids after successfully unclogging one of them. These things just feel right. They seat properly. They dont completely smoosh the collar grommet (like the Borsol's do). The bus runs best with these. I still have the ever so slightest off-idle, low rpm hesitation mainly when cold -- but really the bus runs good. I'll see what kind of fuel economy I have now, and hook up the LM2 later this week -- I just did the tuning procedure and left it as is. Nice 1k idle with 50rpm uptick finger off. Airbox all hooked up I'm at a 975 idle, and everything sounds solid.

I even had another bay window bus follow me into a gas station to compliment on how well it "sounded",.. the dual carbs definitely has a unique and most excellent exhaust note.

I never bothered trying the fixed Solex fixed 55 idle jet screws -- but seems like something every dual carb bus owner should keep in the vehicle incase of a solenoid failure -- particularly with the aftermarket solenoid situation.

If anyone has a source for the Pierburg solenoids with the correct part number (55's in 12V, which should be #111 129 413B please let me know!
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Re: The Goose: Converting back to Dual Solex PDSIT-32/34

Post by Amskeptic » Tue Aug 14, 2018 6:38 pm

xyzzy wrote:
Sun Aug 12, 2018 9:10 am
A) I installed my "original" solenoids after successfully unclogging one of them. These things just feel right. They seat properly. They dont completely smoosh the collar grommet (like the Borsol's do). The bus runs best with these. I still have the ever so slightest off-idle, low rpm hesitation mainly when cold -- but really the bus runs good.

B) the dual carbs definitely has a unique and most excellent exhaust note.

C) I never bothered trying the fixed Solex fixed 55 idle jet screws -- but seems like something every dual carb bus owner should keep in the vehicle incase of a solenoid failure -- particularly with the aftermarket solenoid situation.
a) remember that the new car reviews mentioned a host of driveability issues when adjusted to US emissions specs. If you are this close, then call it done, and allow future tweaks to inform you further. You may find that a change in seasons will require a few adjustments as ambient air cools down.

b) oh, I miss my Road Warrior's engine. Dual carbs under full throttle make a unique bark.

c) I had a couple of solenoid failures that needed only a five minute r&r carbs spray. For an electrical failure, you can just unscrew it a quarter turn or so, and you're back in business.
Colin
BobD - 1978 Bus . . . . . . . . . . .111,130 miles
Chloe - 1970 bus . . . . . . . . . . . 206,787 miles
Naranja - 1977 Westfalia . . . . . 86,570 miles
Pluck - 1973 Squareback . . . . . 55,510 miles
Alexus - 1991 Lexus LS400 . . . 72,113 miles

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

Post by xyzzy » Tue Aug 14, 2018 8:09 pm

Amskeptic wrote:
Tue Aug 14, 2018 6:38 pm
a) remember that the new car reviews mentioned a host of driveability issues when adjusted to US emissions specs. If you are this close, then call it done, and allow future tweaks to inform you further. You may find that a change in seasons will require a few adjustments as ambient air cools down.
I think I'm close, but it's still not right. Now with my old solenoids, doing the tuning procedure I'm running 11MPG. Exhaust smells rich. I haven't hooked up the LM2 again yet...

Currently I'm either doing the PDSIT tuning procedure and running very rich with no real major stumbles, or AFR tuned correctly at idle and light cruise on the LM2 and have off-idle mid-range leaning out.

Studying the Bentley procedure vs your PDSIT tuning procedure, the one discrepancy that stands out with my symptoms is setting the throttle plate with stop screws. Bentley suggests sticking a gauge up there vs your 1/4 turn after contact. Perhaps the throttle is a little too open on the stop screws -- I think this would explain why I'm too rich after the tuning procedure, and after adjusting with the LM2 I'm too lean off-idle. With the LM2 I end up having to turn down the mixture on the carbs and up on the central idle vs the tuning procedure....I also have not done the AFR readings during the tuning procedure like Bentley says setting to 3-5% on the carbs with no central idle, so I can try that.

I will try the feeler gauge to set the throttle plate gap and the NOS Pierburg 12V 55 solenoids I found in Europe that are in the mail next.
---
1973 Westfalia
Encinitas, California USA

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