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

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

Post by xyzzy » Mon Aug 05, 2019 9:50 pm

So, just finished my second visit from Colin. I'll leave details on the overall visit on his 2019 lap forum.

viewtopic.php?f=78&t=13895#p233594

We:
1. Adjusted Valves (twice for #2!)
2. Changed Oil, Filter, Strainer.
3. Changed Plugs
4. Verified timing was still good.
5. Colin did his tuning procedure, and experienced the "hesitation" (maybe surge?)

*DISCOVERED AN AIR LEAK IN A SMALL HOLE ON THE METAL RIM OF THE EGR VALVES MANIFOLDS!!!!*

How did I never notice this before? Robbie? I thought we had gone nuts with the starting fluid looking for any leaks... Unbelievable. I did have the rubber cap on the nipples on both EGR valves, but never noticed the small hole on the rim since it's facing the firewall. Mitigated with some HVAC tape.

6. Redid tuning procedure since there was considerably less airflow after fixing the leak. Now we're really getting close to actual Nirvana.
7. Removed the sliding door Jalouise and addressed two small rust areas in both lower corners. Grinded, filled the worse of the two, primered, and painted.
8. Grinded, filled, primed and painted a small rust area on the bottom rear corner of the passenger door.

Before Colin showed up I also removed the remainder of the AC system from under the bus -- boy what a difference that makes.

Image

Image

I'm excited to see how it runs, and what kind of fuel economy I'm getting now. It sure sounds nice and drives amazing.
---
1973 Westfalia
Encinitas, California USA

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

Post by asiab3 » Tue Aug 06, 2019 7:18 pm

Congrats on finding your path to Stock Volkswagen Bliss! I have been in and out of it ever since we fiddle-fucked ALL OVER that engine compartment with Gum Out Carb Choke and Parts Cleaner this past spring.

Your hesitation is gone?! It was occurring under the exact conditions that EGR would have been mixed in... Coincidence?

Did you get a fuel pressure reading after I discovered my guage was bad? Did ya??

RobbieInMichiganOrMaybeIndiana?
1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.

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

Post by xyzzy » Mon Aug 12, 2019 10:22 am

Ok so, still having the mid-range lean-out "hesitation". Car runs beautifully at idle, cruise, and highway. Given how substantial the lean-out numbers were on the analyzer (14-16.5), I'd like to get this resolved.

Given the fact that multiple-efforts with different people missed that leak from what should have been an obvious hole on the rim of that EGR valve, maybe a smoke-test is in order? Are there any other oversights like that from an EGR delete that should be double checked?

Robbie: We didnt check the fuel pressure. But this behavior was same with the old pump and the new one.. I will get a gauge though..
---
1973 Westfalia
Encinitas, California USA

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

Post by xyzzy » Fri Aug 16, 2019 1:31 pm

Had a smoke test done at a local vintage Porsche shop here in Encinitas -- no leaks. Which is kind of disappointing!! :spam1:
Is there any part of the EGR-deletion that would create an air leak under load mid-range?

Or is this now an issue of I need to create a richer mixture in the carbs? I'm running 135 mains (per Satchmo and others who have run these on a 2L), and 140 airs which are stock with the carb.

Thoughts?
---
1973 Westfalia
Encinitas, California USA

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

Post by KosmicK1100 » Fri Aug 16, 2019 3:33 pm

xyzzy wrote:
Mon Aug 05, 2019 9:50 pm
Before Colin showed up I also removed the remainder of the AC system from under the bus -- boy what a difference that makes.
I am curious, what is the difference you speak of upon removal of the AC system?
My 79 Westy has a ton of AC stuff bolted to its undercarriage.
Cheers!

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

Post by asiab3 » Sat Aug 17, 2019 5:36 pm

Are your pilot jets removable, or are they permanently mounted to the cutoff solenoids? I wouldn't hesitate to go .05mm leaner on the pilot fuel jet if they were easily replaceable or swappable. If they cutoff solenoids are your only pilot mixture adjustment, I'm not sure you want to go drilling those.

Can you give the fuel bowl level half a millimeter higher fuel level and see what happens? It felt to me like the little jitter was at BARELY any throttle, so we're just looking at one or two transition ports here.

KosmicK1100, I'm assuming xyzzy means the under dash AC blower housing. That makes wiring the dashboard SIGNIFICANTLY easier than working with a giant blower housing that blocks light, sight, and access.

Robbie
1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.

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

Post by xyzzy » Sun Aug 18, 2019 2:27 pm

The solenoids are idle-jets and orifices are not removable.....? I'm running the factory 55 solenoids...

The carbs have a removable main jet (im at 135 per Satchmo and others moving to 2.0 liters on these carbs), and air bleed (140), the emulsion tube is pressed-in and not removable that I'm aware of). Runs great at cruise or on the highway, and a slight leaning mid-range off-idle. It idles beautifully and has an amazing exhaust note.

My economy is now 17 highway and 14 around town, and I have a clean smoke test.

My understanding of the idle jet solenoids is that these affect idle only. Since I have a perfect idle, I'm assuming the idle jet solenoids are ok.... Off-idle it should hit the transition ports, and then the mains...... right? I have great acceleration when getting on it, and lots of power...

If I'm getting a mid-range leaning, then I either am having unwanted air introduced, or need to increase (?) the air jet?

Since I have the EGR delete, is there any places I need to check for a leak under load that would traditionally be filled by the EGR system? Like the small holes on the rim of the EGR valves that was not blocked off that Colin discovered..
---
1973 Westfalia
Encinitas, California USA

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

Post by Amskeptic » Wed Aug 21, 2019 5:16 pm

xyzzy wrote:
Sun Aug 18, 2019 2:27 pm
Runs great at cruise or on the highway, and a slight leaning mid-range off-idle.
It idles beautifully and has an amazing exhaust note.
economy is now 17 highway and 14 around town,


My understanding of the idle jet solenoids is that these affect idle only.
Since I have a perfect idle, I'm assuming the idle jet solenoids are ok....
Off-idle it should hit the transition ports, and then the mains...... right?
I have great acceleration when getting on it, and lots of power...

If I'm getting a mid-range leaning, then I either am having unwanted air introduced, or need to increase (?) the air jet?

Your best experiment is to crack loose the cut-off jets by let's say 1/16th of a turn.
This will richen the idle. Who cares? This is an experiment:
Drive with the equally cracked-loose cut-offs. Is mid-range hole gone?
Restore to initial condition and report back.
ColinInTayaxass
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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

Post by xyzzy » Fri Aug 23, 2019 7:53 am

Ok. I unscrewed the idle jet solenoids a touch (id say between 1/8th and 1/16th). I noticed that when they are "tight" it went from very little resistance, to feeling "seated", as is, all the way in. I couldn't tell any real difference at the mixture reference hose, but when I drove it this way the slight hesitation/leaning seemed to be gone!

I also removed one of the solenoids and was shocked to see the condition of the solenoid itself (one year at the beach). Particularly interesting was the rubber insert in the collar is rotted and fully compressed when it was screwed in.

Image

Hard to believe these things looked relatively new a year ago. Below is a pic of the same solenoid a year ago, the one labeled "OLD":

Image

I'm unfamiliar with what the internals to the carb are where this solenoid screws in, but could this be as simple as it was screwed too far in against an internal wall of the carb itself? Perhaps a new rubber insert at the collar would keep the solenoid snug but a little further unscrewed?
---
1973 Westfalia
Encinitas, California USA

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

Post by xyzzy » Sun Aug 25, 2019 8:56 am

Ok. quick update. After a fresh wash and wax yesterday, I went ahead and pulled both solenoids. The rubber grommets in the metal collars were completely compressed and one of them was crumbling when I removed it. I re-installed them with two new rubber grommets, and just hand tightened it until it started to feel snug, and fired it up. Idle was so rich it wouldnt stay running. Whaaaaaaaaat???

Turned down each carb 1/4 turn, same thing, wouldnt idle. Tried another 1/4 turn lean, same thing. Ok.

Disconnected central idle, pulled retard, and now would idle, but mixture hose still showing incredibly rich. WTF?

Stumped. Thought about it for an hour, and then figured the solenoids had to be unseated and allowing way too much fuel in. Left the carb settings, now 1/2 turn leaner, and slowly tightened each solenoid until idle sprang back to life.

So, these solenoids do need to be "seated", but these rubber spacers and collars are clearly very critical in seating the solenoids properly. Mixture hose showed a little lean, so richened each one up 1/4 turn, hooked up central idle, and she purrs like a kitten.

It seems the mid-range hesitation is gone, or at least, appears to be. I'll see what kind of economy I'm getting now.

When Colin left, ran like a champ, had a leaning mid-range, was 13mpg city, 17mpg highway. With the new solenoid grommets, I'm leaned 1/4 turn on each carb from when Colin was here. I will report back after a week of commuting with some fuel economy numbers, and I'll try and hook up the LM2 and get some AFR numbers.

She sure runs nice.
---
1973 Westfalia
Encinitas, California USA

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

Post by BusBassist » Sun Aug 25, 2019 12:37 pm

Am anxious to learn of your results xyzzy as I'm planning to take the dual carb plunge next spring/summer.
Currently, my single carb is giving me about 12.5 mpg around town and 14.5 on the highway. AND the carb is running very rich, so much so that the mixture screw is all the way in and the engine still runs. I will say that despite the limitations of the single carb, the engine is running fairly well. Am a little nervous about switching to duals since it appears they are pretty finic-ky and susceptible to the slightest deviation or change.
Late 73 Bay w/a transplanted 914 Engine.

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

Post by xyzzy » Sun Aug 25, 2019 8:28 pm

BusBassist:

Don't get me wrong, my bus runs amazing, and I've driven it almost 10k miles since Colin's visit where we installed these original dual carbs without ever having a problem!

I'm fairly deep into the Nirvana rabbit hole with these. Robbie can come over and drive it when he gets back and give you his thoughts!
---
1973 Westfalia
Encinitas, California USA

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

Post by asiab3 » Sun Aug 25, 2019 10:03 pm

Ayyy, glad you’re enjoying your factory engineering a little more! I am currently enjoying the NOS Type 1 idle solenoid you gave me, but the run from New Jersey through Manhattan to Brooklyn and back to Harlem today really really really tested the limits of a stock VW bus... an off-idle lean spot would have been detrimental to my bumpers, so I hope you can finally lick your hesitation, once and for all!

BusBassist has a factory 1.7 Porsche 914 engine that might present fun challenges for the bus carburetors.... How will a high-revving 1700cc compare to a 2L bus engine? I don’t know, but I want to find out. :)

Robbie
1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.

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

Post by BusBassist » Tue Aug 27, 2019 8:45 am

I appreciate both responses asiab3 and xyzzy.
Don't get me wrong, my bus runs amazing, and I've driven it almost 10k miles since Colin's visit where we installed these original dual carbs without ever having a problem!
I'm glad to hear things are working well for you xyzzy. I imagine this system, when fully functioning is spectacular; it's just intimidating to a novice like me.
but the run from New Jersey through Manhattan to Brooklyn and back to Harlem today really really really tested the limits of a stock VW bus
Robbie, having driven many times in NYC, I can understand the need to protect your bumpers. In NYC, one can measure the distance between cars and people in millimeters. And you've given me a little pause for thought when you mention my high revving engine and dual carbs. I wonder if I should consider an L-jet system instead (if I could even find one!)?
Late 73 Bay w/a transplanted 914 Engine.

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

Post by Amskeptic » Fri Aug 30, 2019 7:01 am

asiab3 wrote:
Sun Aug 25, 2019 10:03 pm
New Jersey through Manhattan to Brooklyn and back to Harlem today really really really tested the limits of a stock VW bus ...
Robbie
How so? Did it test the limits of the bus, or the driver?
Colin :cyclopsani:

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BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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