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

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wcfvw69
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Re: The Goose: Converting back to Dual Solex PDSIT-32/34

Post by wcfvw69 » Sun Jun 03, 2018 11:21 am

Curious about the "bucking" that you're describing? SO, you're on the street. You let the clutch out as you give it gas. Does it fall on it's face and load up like it's taking the engine a minute to catch up and the RPMS increase?
1970 Westfalia bus. Stock 1776 dual port type 1 engine. Restored German Solex 34-3. Restored 205Q distributor, restored to factory appearance engine.

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

Post by xyzzy » Sun Jun 03, 2018 11:53 am

wcfvw69 wrote:
Sun Jun 03, 2018 11:21 am
Curious about the "bucking" that you're describing? SO, you're on the street. You let the clutch out as you give it gas. Does it fall on it's face and load up like it's taking the engine a minute to catch up and the RPMS increase?
I think that's a good description. As soon as you're in gear and try to give it gas it feels like it loses power then regains and lunges, and repeats. If you really get on it and give it a lot of throttle and higher rpms it seems to lessen (maybe go away?). It's significant enough where it's barely driveavle.

Revving it up in neutral feels and sounds great.

Once the beach traffic dies down I'll try and get a video from the engine compartment as I drive it around the block.
---
1973 Westfalia
Encinitas, California USA

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

Post by xyzzy » Mon Jun 04, 2018 8:20 am

Day Two...

Pedal to the floor and release, bump the key, fires right up to fast idle. Still can't believe the difference there.

If there was one thing in particular I learned with Colin, it was be precise in your wording. So, instead of saying "bucking", let's go with "stumbles and hesitates with light throttle while under load".

1) Revving up at idle is good. Timing with retard and advance hoses disconnected and unplugged maxes at 28 degrees at 3500 rpm. Sounds great to me.

2) When driving, as you begin to accelerate, the vehicle stumbles and hesitates, and as you give it more throttle it lessens and as you really get on the pedal it has good power and the stumbling seems to go away. It's very hard to drive without brisk acceleration. With brisk acceleration there is good power, feels smoother and more powerful than my previous 009/baby weber setup.

3) Exhaust seems to pop a lot while its stumbling. Downshifting to second with no throttle down a short not to steep hill at 20mph gave a "run for cover" backfire.

Reminder that bus ran great with an 009 and baby webers.

Debugging Strategies: (Thanks Colin!):

0) Verify that #3 cylinder is participating at idle by pulling the spark plug wire from the distributor. Will try carefully spraying WD-40 around the manifold gasket to verify there is no leak.

1) The hoses from the brake booster through the firewall to the booster pipe look new. These were replaced by Buslab when I first purchased the vehicle as it had been sitting in a garage for 28 years. Buslab used those nasty crimp on clamps so I may have to cut the hose and replace it. I am going to try and plug the hose at the brake booster and see if that fixes things.

2) I have ordered two new idle jet solenoids (55's) from bus depot. The current ones clicked fine when we tested them for clicking before installing them. They are probably original so who knows. Both seemed to work fine in the right carb -- pulling the connector would show change, and neither seemed to work in the left carb -- pulling connector exhibited no change. They both have collars and installed with a good seal...


Stay tuned!
---
1973 Westfalia
Encinitas, California USA

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

Post by xyzzy » Mon Jun 04, 2018 4:05 pm

Progress...

Sprayed WD-40 around the manifolds and booster elbows at idle -- no change.

Pulled plug at #3 at idle, no change. Did it a few times to triple check and noticed that once I did hear a verrrrry slight change. Decided to pull the cable, and wouldnt ya know it, not only was it cracked, but a much different cable then what was on #2 and #4. In the picture below, the cable on the left is the style that was on #2, #4, and the one in the middle was on #3. You can kind of see the crack in the picture. The cable on the right is the new replacement Bosch.

Image

The wire on #1 had solid black ends, had the factory computer (inductive?) pickup connector on it and a VW stamp so probably original. It just seemed like a better quality cable then the cracked one from #3. I went ahed and replaced all of the spark plug wires with the new Bosch wires. I left the center coil wire since the connector was different and figured it's working and looks original.

Image

So, #1, #2, and #4 all exhibit a very noticeable change at idle when pulled from the distributor. #3 now exhibits a noticeable change but isn't as much of a change as the other cylinders -- but noticeable nonetheless.

Took it around the block, even smoother and even more power, but the stumbling/hesitation is still there -- perhaps not as severe? Lots of popping when off the throttle in gear, did get one good backfire downshifting to 2nd again. I also notice that when i apply the brake that I am indeed getting a change in RPMS and a vibration -- I noticed it this time as the seat was folded down flat and it was moving side to side enough to squeak whenever I pressed the brake pedal while at a stop.

I will plug the vacuum line at the brake booster tomorrow and report back. I did try pumping the brakes after turning off the car and there was no change in pressing it repeatedly. Holding down the brakes and starting the bus exhibits no change either.

It definitely feels like its awfully close.
---
1973 Westfalia
Encinitas, California USA

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

Post by satchmo » Mon Jun 04, 2018 5:07 pm

The popping and backfiring means there is some unburned fuel being dumped into the exhaust; probably from the #3 cylinder. It can also mean there is a small air leak at the exhaust manifold to head junction, or the manifold itself.

I'd pull the spark plugs and take a look to see if #3 is radically different from the others. If it is, replace it. Make sure all the plugs are appropriately gapped. Re-install. Then try again.

You're getting close...

Satchmo
By three methods we may learn wisdom:
First, by reflection, which is noblest;
second, by immitation, which is easiest;
and third, by experience, which is bitterest. -Confucius

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wcfvw69
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Re: The Goose: Converting back to Dual Solex PDSIT-32/34

Post by wcfvw69 » Mon Jun 04, 2018 7:20 pm

WD40 isn't that flammable IMOP. Go get a can of starting fluid or brake cleaner and spray it at all the possible vacuum leak spots with it at idle. I like the idea of checking the spark plugs. Maybe #3 is a dud.

The other thought is to pull the restored distributor and put the 009 in as a test. Sometimes even brand new condensers can be bad. They will act ok at idle but act up under load. A coil can do the same. If swapping the distributor cures it, then suspect the condenser.
1970 Westfalia bus. Stock 1776 dual port type 1 engine. Restored German Solex 34-3. Restored 205Q distributor, restored to factory appearance engine.

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

Post by xyzzy » Tue Jun 05, 2018 7:08 am

Pulled the plugs this morning. The original plan was to swap them with some B6ES, however,.....

Left is #3, right is #1. Presumably these were installed with the new engine 2L engine (16.5k miles ago).

Image

Image

Image

UPDATE: Called Buslab, asked them why the shorter plugs were in there, they said there definitely shouldn't be and a tech must have put the wrong plugs in. Buslab suggested using thread chaser first to remove any buildup from the lower threads since the shorter plugs were run this entire time. Per Colin: NO thread chaser -- I'll carefully clean it with a rag carefully instead!!

Will dive into the brake booster vacuum this afternoon.
---
1973 Westfalia
Encinitas, California USA

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

Post by Amskeptic » Tue Jun 05, 2018 10:55 am

xyzzy wrote:
Tue Jun 05, 2018 7:08 am
Pulled the plugs this morning.
Will dive into the brake booster vacuum this afternoon.
Hey Earle!
We so very need the updated results of your booster issue before we can drive the diagnosis forward.

Bill, we found 16*ATDC with the retard connected AND a proper 28*BTDC with the centrifugal and 40* vacuum advance. This substantial retard may be giving us a transitional hesitation. I told Earle that I could have/would have bent the post on the retard unit to limit its excessive travel. We may get to that . . . :cyclopsani:
BobD - 78 Bus . . . 112,660 miles
Chloe - 70 bus . . . 206,845 miles
Naranja - 77 Westy . . . 121,400 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 91 Lexus LS400 . . . 92,435 miles

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

Post by satchmo » Tue Jun 05, 2018 11:04 am

Wow, those spark plugs look nasty. And they are the wrong size. It could be that #3 just wasn't able to make a spark anymore with the cracked connector and all that build up on the terminals.

Satchmo
By three methods we may learn wisdom:
First, by reflection, which is noblest;
second, by immitation, which is easiest;
and third, by experience, which is bitterest. -Confucius

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

Post by xyzzy » Tue Jun 05, 2018 1:56 pm

Ok. Pulled the hose from the Brake Booster -- it was still holding vacuum when I disconnected it. Plugged it up, drove around. Stumble/hesitation is still there. My brakes didn't work any worse than usual with it unplugged!

Image

Image

Next, wanted to eliminate the hose, pipe, hose, check valve, and more hose before the brake booster balance pipe in the engine compartment. Cut the &#$*@$) hose crimp off the booster pipe behind the firewall, and plugged the pipe itself and the stumble/hesitation is still there.

Image

Put a normal hose clamp back on the hose to the pipe through the firewall since I have a correct new one coming since this one is cut anyways. Connected it all back up, still have the stumble/hesitation.

The idle slightly lowers and engine vibrates when touching the brakes -- so that would mean the diaphragm (or something) in the booster is bad as it would be drawing vacuum from the engine?
---
1973 Westfalia
Encinitas, California USA

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

Post by xyzzy » Tue Jun 05, 2018 4:33 pm

Amskeptic wrote:
Tue Jun 05, 2018 10:55 am
xyzzy wrote:
Tue Jun 05, 2018 7:08 am
Pulled the plugs this morning.
Will dive into the brake booster vacuum this afternoon.
Hey Earle!
We so very need the updated results of your booster issue before we can drive the diagnosis forward.

Bill, we found 16*ATDC with the retard connected AND a proper 28*BTDC with the centrifugal and 40* vacuum advance. This substantial retard may be giving us a transitional hesitation. I told Earle that I could have/would have bent the post on the retard unit to limit its excessive travel. We may get to that . . . :cyclopsani:
Since I'm now running a 2L, and this DVDA distributor was a 1 year only design for the 1973 1700cc, is that why we're seeing 16* ATDC at idle with excessive retard?
---
1973 Westfalia
Encinitas, California USA

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wcfvw69
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Re: The Goose: Converting back to Dual Solex PDSIT-32/34

Post by wcfvw69 » Tue Jun 05, 2018 6:38 pm

Amskeptic wrote:
Tue Jun 05, 2018 10:55 am

Bill, we found 16*ATDC with the retard connected AND a proper 28*BTDC with the centrifugal and 40* vacuum advance. This substantial retard may be giving us a transitional hesitation. I told Earle that I could have/would have bent the post on the retard unit to limit its excessive travel. We may get to that . . . :cyclopsani:
Bus & Pickup 1973 * 1700 Manual Trans
Distributor: VW 021-905-205J, Bosch 0231 173 009 or 010 > 021-905-205N, 0231 181 005
Can Use: VW 021-905-205N, Bosch 0231 181 005
Points: 01 011
Condensor: 02 054
Rotor: 04 033
Note: Originally equipped with Speed Limiting Rotor 04 016 (5400rpm)
Cap: 03 010
Coil: 00 015 (Blue Coil: 00 012)
Vacuum Can: 07 113
Ignition Wires: 09 171
Spark Plug: W8CC
Timing Set At:: 10deg ATDC @ 800-950rpm w/strobe, vacuum hose(s) connected
Advance/Retard Range: Vacuum: 7-12deg Adv, 16-18deg Ret; Centrifugal: 9-14deg @ 2000rpm, 21-25deg @ 3400 rpm


Colin/Earle,

Here's the specs for that distributor. When it was run on my Sun distributor machine post restoration, the vacuum canister was right in spec on both the advance and retard. This spec sheet shows it should be timed at 10* ATDC which is unusual for the DVDA distributors that normally have their timing set at 5* ATDC.

I'm not sure what Bosch/VW had in mind for the retard to be so many degrees unless it was for smog passing purposes. It was the tough smog laws of 1973. Clearly VW installed this distributor/vacuum can when these where new back then and they ran fine.

I think I suggested via email to Earl to yank that DVDA out and install the 009 as a quick test. Set the 009 timing to 7.5BTDC and see how the engine reacts to it. Condensers can act bizarre too, even new ones. If the 009 ran good, then he knows the condenser and distributor are ok.
1970 Westfalia bus. Stock 1776 dual port type 1 engine. Restored German Solex 34-3. Restored 205Q distributor, restored to factory appearance engine.

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

Post by satchmo » Tue Jun 05, 2018 7:50 pm

The main reason for the substantial retard on the distributors in 72-74 was to activate the central idle system on the dual carb setup and get maximal airflow to the cylinders at idle. Colin may chime in on that. There may have been some element of idle emission reduction at play as well.

Satchmo
By three methods we may learn wisdom:
First, by reflection, which is noblest;
second, by immitation, which is easiest;
and third, by experience, which is bitterest. -Confucius

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

Post by xyzzy » Tue Jun 05, 2018 8:45 pm

So other than the 2.0L hydraulic vs the 1700cc, not much else is different (no EGR, AC pump removed) -- and most parts are the same ones on it when it was sold new.

I have two new idle jet solenoids (55) in the mail, will arrive Thursday. The ones in the carbs now are probably the original ones sold new with the bus. I will change the plugs and the jest when they arrive Thursday.

In terms of the brake booster not functioning (brakes acting no different with it disconnected entirely) and idle dropping whenever you press the brakes it sounds like a need a new one. Anyone happen to have a source for a good replacement, or even a new old stock? Why go half-way now! :headbang:
---
1973 Westfalia
Encinitas, California USA

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

Post by Amskeptic » Tue Jun 05, 2018 10:02 pm

wcfvw69 wrote:
Tue Jun 05, 2018 6:38 pm
Timing 10deg ATDC @ 800-950rpm
Advance 7-12deg Adv
Retard 16-18deg
Centrifugal 21-25deg @ 3400 rpm

Here's the specs for that distributor. When it was run on my Sun distributor machine post restoration, the vacuum canister was right in spec on both the advance and retard. This spec sheet shows it should be timed at 10* ATDC which is unusual for the DVDA distributors that normally have their timing set at 5* ATDC.
Bill, it is not unusual. 5* ATDC was indeed to improve airflow through the central idling (and the Pict3 bypass Type 1 carburetors), yes. But the 10* specification was exclusive to the air-pump-equipped '73-'74 buses only.
It was the timing specification for MY VW bus for thirty years! Thirty years of 10* ATDC. I have met it in many many many other factory dual carb buses, dhoch14, greenolivemedia, volksfolk74, satchmo, ChiTwnVW, Turk, needvwparts, Birdibus, cooperm81, iwantmybustorun, the list goes on.
wcfvw69 wrote:
Tue Jun 05, 2018 6:38 pm
I'm not sure what Bosch/VW had in mind for the retard to be so many degrees unless it was for smog passing purposes. It was the tough smog laws of 1973. Clearly VW installed this distributor/vacuum can when these where new back then and they ran fine.
I am sure what VW had in mind for the 10* retard specification. Remember the air pump? The air injection system with the air pump? It HAD to have damn good and hot exhaust for the injected air to burn off any remaining hydrocarbons. 10* retard at idle helped to make sure combustion was happening into the exhaust manifold as the exhaust valve opened. Many many many European cars, like my beloved Mercedes and BMWs of the 70's and my '77 Porsche 911 engine were also using air pumps with thermal reactors and they all needed retarded ignition timing at idle.
wcfvw69 wrote:
Tue Jun 05, 2018 6:38 pm
I think I suggested via email to Earl to yank that DVDA out and install the 009 as a quick test. Set the 009 timing to 7.5BTDC and see how the engine reacts to it. Condensers can act bizarre too, even new ones. If the 009 ran good, then he knows the condenser and distributor are ok.
Nope. We are not going on goose chases (get it, Earle, "goose chase"??). We are going to follow the diagnostic track set out and we will report back as we check off "what it is not", which is as, if not more, valuable as exploding possibilities of what it may be. I know condensors, even the new ones, and this is not that sort of hard ignition based cutting out.

So let's get back to the math and why I find so many older distributors with greater and greater centrifugal range. We are absolutely committed to NOT exceeding 28* at sea level with a stock engine. Done. So why did my distributor, which we ran up on your machine, give me 445* the day after our visit? Why did I have to reduce the max centrifugal timing to 24-25* BTDC @ 3,400 rpm to bring my head temps back down to low 400s? Why is my idle timing at 850 rpm now 3* After TDC?? I cannot answer this, Bill. We tried to figure out what might make a distributor get sloppy, we looked at weights and their action against the upper shaft/breaker lobe. We could not find a visible reason for my observations all across this country. Yet, I have to stand by my observations, and I have to live by them as I drive long hot highway headwinds. The BobD, when new, had a certifiable 7.5* BTDC idle timing, and the centrifugal went no further than 28*. Now it is at barely 2* BTDC idle to maintain that 28* max. Why? 10 point essay (we discussed one possibility and I offered it as a tip for your customers)


Maybe Earle and I can figure out a way to "shim" the retard stop on his distributor. I know the numbers. I know them. We need to narrow down the range.
a) if we are committed to 28* BTDC centrifugal max, and HIS distributor has 22* centrifugal range, then the centrifugal idle timing would be 6* BTDC, right? And we would subtract the requisite 16* of retard for a retard timing at idle of 10* ATDC. Right? Not what we are getting. We have (chime in Earle) 16* ATDC AND a max of 28* allowed. I have to run! They are closing this joint out from under me!
Colin
BobD - 78 Bus . . . 112,660 miles
Chloe - 70 bus . . . 206,845 miles
Naranja - 77 Westy . . . 121,400 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 91 Lexus LS400 . . . 92,435 miles

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