TheSamba.com :: View topic - Type 4 with Weber 32/36 DFAV....initial settings?

Tue Dec 18, 2012 8:55 pm

I need tech info on adjusting a Weber/Progressive 32/36 DFAV on a 1800cc Type 4 engine. The engine was most likely built with dual carburetors. The engine is now equipped with a used Bosch 009 distributor equipped with vacuum advance. I have adjusted the valves, reset the points and set basic timing following the Bentley service manual. The electric choke was way off, and I have preliminary set it cold to the point where it is just about to open the choke. The electric choke now seems to work fine; it slowly opens up with the ignition circuit on, and also is closed when cool. I would say that when warmed up, the choke keeps the butterfly open to about 3/4 of full travel, and accelerator linkage overcomes this just fine. But I don't know how to set the choke per specifications, so I might still be wrong.

The biggest problem seems to be high idle (not yet read with a meter to determine actual RPM, but probabably 2,000-2,500 RPM) and failure of engine to stay running through accelerator range without manipulating the butterfly when the accelerator is held at any given range.

To put it another way, I accelerate past idle, stabilize the RPM, but then after about 10 seconds, I have to manipulate the butterfly to keep it from dying. Often, when it does die, it ends with a half-hearted backfire. That little backfire concerns me that I either 1) have a fuel metering and an airflow issue or 2) didn't set my timing perfectly; and I plan to use a timing light once the carb behaves.

I am also at a loss to figure which port to use for vacuum advance. The carb has two ports, of different sizes. The diagram I did find showed the larger port is used for vacuum advance, but when hooked up, it drove the RPMs higher. Right now, I have the ports plugged and vacuum advance disconnected. The other distributor that was on it was an aftermarket 009 in questionable condition and without vacuum advance. That was replaced with this other used distributor.

I find it difficult to get anywhere with a lot of these threads on this idea. :( It seems like most people are either getting opinions on what carb to use, or flaming on someone for using such-and-such carb set-up. Or, they don't follow up with the results of someone's advice, or the thread starts out great but gets hijacked.

What I need is a service bulletin, procedure or process from which this carb will be initially set-up, with a process towards final tuning. I've looked at Ratwell and Weber, but I didn't see it. Actually Weber's page was a bad surprise. They actually state: "B. Testing the Idle Speed Adjustment:
With the engine at normal operating temperature, adjust to manufacturer's specs." :?:

I really think this topic is likely widely discussed, so maybe I just suck at finding usefull threads. Anyone?

Tue Dec 18, 2012 9:50 pm

as far as I know all Bosch 009's are a full mechanical advance.007 and 034 are sva or svda. Also I have had two 32/36 webbers on mine in the past and do not recall any manifold vaccuum access on either, hence the conversion to the 009 mechanical. 16 years with the webber and 009 and I was neve 100 percent happy. 1700 was a dual set up when new as was 1974 1800.
009's are not all equal. I seem to remember they can swing from 19-21 or 22 degrees advance. My best advise is to set the timing at full advance from 30 to 32.
Mine did run ok with an 009 and the webber in very warm weather but you might start researching going dual again. I recently did that and went back to a single vaccuum dual advance distributer. This required some mods to the kadron 40's I am now running. For me it was worth the the coin.
Webber builds some great stuff but mine never ran correctly with that set up.
I did a lot of research trying to solve similar problems. Best guy I met was a cat called Jeff Lain at the Kaddie Shack in Pasedena. What he suggested was not cheap but my dear old Busruns better now than it ever has in our 16 year affair. I've put 500 miles on her in the forst week since, most just for fun. It has never run this well.
I know this was not the answer you were looking for but I tried for YEARS to get the single progessive to work andjust could not be 100 percent happy.'
MK

Tue Dec 18, 2012 9:59 pm

set the timing to 28 - 30 degrees BTDC at 3500 RPM with the distributor hose off, then reconnect it.

Set the mixture lean best idle. You turn the idle mixture screw about 1/8 turn at a time, wait a few seconds and see if the idle is up or down. Once you find the spot where the idle is fastest then turn the screw in about 1/8 turn. That will get you close. Try to keep the idle speed around 850 while you are doing this because if you let it go too high then the distributor advance will come in and trick you.

Your choke should open almost straight up and down when it is hot.

Tue Dec 18, 2012 10:53 pm

Thanks, guys. For what it's worth, here are a couple of pictures of the distributors. The one on the left was on the bus when I got it, and without a long discussion, I decided I'd try out the one on the right. Both seem to be 009's

The Bosch (donor) is at 5 o'clock and the other 'on bus' is at 7 o'clock. Not that it matters a whole lot, apprently. I have both rotors at the No. 1 cylinder, but look close, and you can see where the position of the engaging lugs where they mate up with the driveshaft is different between the two.
Anyway, it's not as important as following up on the fuel/air and idle settings. Thanks SGKent, for that! I will be out of town for the next two days, but I will follow up with a post after I try your advice.

I also have received advice that the Progressive set up does not do well on a Type 4 due to no preheat and fuel/air mixture condensing on the long path to the head.

marken, I do actually have a donor engine complete, and with OEM volkswagen dual carbs, but all of it needs a thorough going through (rebuild). If I can't get this Progressive set-up to work, I night look into rebuilding the VW gear.

Here's my current joy, complete with controversial fuel filter location :wink: :

And from the driver's side: (the filter clips are on hand, just removed while screwing with it).

Wed Dec 19, 2012 4:38 am

that just doesn't look safe :shock:

Wed Dec 19, 2012 7:29 am

Wasted youth/adulthood wrote: Thanks, guys. For what it's worth, here are a couple of pictures of the distributors. The one on the left was on the bus when I got it, and without a long discussion, I decided I'd try out the one on the right. Both seem to be 009's

Not quite, the one with the vacuum can is a 73 bus distributor, you are reading the wrong numbers: http://www.oldvolkshome.com/ignition.htm#B1973M
If you find you ar getting alot of hesitation try that one but leave the retard side disconnected, the only issue it may have is some Prog's make too much vacuum on the advance port at idle so see what it does idling when you connect the hose.

Wed Dec 19, 2012 12:27 pm

Busdaddy wrote: "Not quite, the one with the vacuum can is a 73 bus distributor, you are reading the wrong numbers:" http://www.oldvolkshome.com/ignition.htm#B1973M

And I have an automatic transmission, so by the page you linked (thanks!) me to, I should have: Bosch 0231 173 007 > 021-905-205F, 0231 173 008

Question: How significant is the difference between those and the distributors for manual transmission application?

Wed Dec 19, 2012 12:54 pm

Wasted youth/adulthood wrote: Busdaddy wrote: "Not quite, the one with the vacuum can is a 73 bus distributor, you are reading the wrong numbers:" http://www.oldvolkshome.com/ignition.htm#B1973M

And I have an automatic transmission, so by the page you linked (thanks!) me to, I should have: Bosch 0231 173 007 > 021-905-205F, 0231 173 008

Question: How significant is the difference between those and the distributors for manual transmission application?

You are p***ing upwind trying to figure which distributor is perfect because you do not have the original carbs, and the distributors are old and worn. The placement and size of the hose connections etc on the carb combined with venturi size etc makes for a specific vacuum draw at the can, which the vacuum can was calibrated for by VW when they built the engine type in 1973. Take the one you have, hook up the advance side as Mark suggested and run with it. It will be close but never perfect. You can't have what it was like new unless you find good parts like those that were on it when it was new. What you have can be tuned to run right most of the time except when carb and manifold icing is present. The carb you have was designed to work on water cooled engines with water heated intake manifolds. Enjoy what you have or you will spend a small fortune in money and time trying to restore it to factory stock.

Wed Dec 19, 2012 1:14 pm

Dual 40mm Kadrons and an aircooled Vanagon svda distributer will make your world a better place.

Wed Dec 19, 2012 3:17 pm

My sons bus has the same setup, and it does work OK.

Our carb has the vacuum port for the dist. It runs good with either 009 or vacuum distributor.

timing seems to be critical, must have it just right, and adjust carb like sgkent says. our idle screw ended up at 2 turns out from seat. start at 1.5 turns, basic initial setting

Wed Dec 19, 2012 5:17 pm

I was always led to belive that so few of the original solex duals were around becase parts were not available. I can't confirm this because I never had them. Maybe they were gone for a while and have come back like sunroof cables for instance. I do really hope you get the ole gal working as well as you can very soon. Man when they work well, there is just nothing on earth quite as joyful as a bus.
MK

Wed Dec 19, 2012 6:52 pm

Wasted youth/adulthood wrote: I need tech info on adjusting a Weber/Progressive 32/36 DFEV on a 1700cc Type 4 engine. The engine was most likely built with dual carburetors. The engine is now equipped with a used Bosch 009 distributor equipped with vacuum advance. I have adjusted the valves, reset the points and set basic timing following the Bentley service manual. The electric choke was way off, and I have preliminary set it cold to the point where it is just about to open the choke. The electric choke now seems to work fine; it slowly opens up with the ignition circuit on, and also is closed when cool. I would say that when warmed up, the choke keeps the butterfly open to about 3/4 of full travel, and accelerator linkage overcomes this just fine. But I don't know how to set the choke per specifications, so I might still be wrong.

The info on setting the choke is out there b/c these carbs have been widely used on VWs and non VWs.

Quote: The biggest problem seems to be high idle (not yet read with a meter to determine actual RPM, but probabably 2,000-2,500 RPM) and failure of engine to stay running through accelerator range without manipulating the butterfly when the accelerator is held at any given range.

To put it another way, I accelerate past idle, stabilize the RPM, but then after about 10 seconds, I have to manipulate the butterfly to keep it from dying. Often, when it does die, it ends with a half-hearted backfire. That little backfire concerns me that I either 1) have a fuel metering and an airflow issue or 2) didn't set my timing perfectly; and I plan to use a timing light once the carb behaves.

The high idle may be caused by the accelerator cable sticking. You don't have a return spring in your picture from the driver's side. It may also be incorrect choke adjustment. As well as the choke butterfly setting there is a mechanism to maintain fast idle until you rev past that point with the accelerator.

Quote: I am also at a loss to figure which port to use for vacuum advance. The carb has two ports, of different sizes. The diagram I did find showed the larger port is used for vacuum advance, but when hooked up, it drove the RPMs higher. Right now, I have the ports plugged and vacuum advance disconnected. The other distributor that was on it was an aftermarket 009 in questionable condition and without vacuum advance. That was replaced with this other used distributor.

The port you have attached the vacuum advance to in one of your photos seems to be the right one (hard to be sure from the photo). The revs will go higher because of the vacuum advancing the ignition because you are above idle. You should have no vacuum advance at idle. This was the one of the hardest things to get right when I had a weber progressive.

Quote: I find it difficult to get anywhere with a lot of these threads on this idea. :( It seems like most people are either getting opinions on what carb to use, or flaming on someone for using such-and-such carb set-up. Or, they don't follow up with the results of someone's advice, or the thread starts out great but gets hijacked.

I find that hard to believe! :lol:

Quote: What I need is a service bulletin, procedure or process from which this carb will be initially set-up, with a process towards final tuning. I've looked at Ratwell and Weber, but I didn't see it. Actually Weber's page was a bad surprise. They actually state: "B. Testing the Idle Speed Adjustment:
With the engine at normal operating temperature, adjust to manufacturer's specs." :?:

I really think this topic is likely widely discussed, so maybe I just suck at finding usefull threads. Anyone?

I didn't find one resource with everything required when I had a progressive. However, there is a lot of stuff out there...

Wed Dec 19, 2012 6:57 pm

You want the choke fully open after about 5 minutes of running. This will mean that you have to set the choke so that it will be too lean on initial cold start, but without manifold heat this is a compromise you need to make. In central California you should be okay with a progressive, especially if you rig up an air preheat system. If you have all the original '74 tin this shouldn't be all that hard to do.

Check the earliest pictures in my gallery to see my system. I now use the original '74 hot air source instead of the heater box as I did when those pictures were taken.

Thu Dec 20, 2012 5:11 am

I really appreciate all of your replies :D ! I got back from work, slept all day, and now I can't really do anything noisy out of repect for the neighbors. While I personally don't mind the idea of tuning up my engine at 4 o'clock in the morning, I think my neighbors will. It looks like I'll be going back to work later this morning, and it will most likely be raining when I get back, so it might be a few days before I can report any progress. I'm pretty stoked about getting this running as best as possible with the parts on hand.

I agree with the comment that I'm not going to get it perfect, because of the non-VW aftermarket alterations and worn out distributor. Right now, I'm all about getting it running as smoothly as possible with the advice given here and later I'll get into some stock applications. I tend to roll towards original, stock plain-jane ideas, but this Progressive was the hand I was dealt. There's still a LOT more to do inside that compartment, so I'm not rushing anything, no panic involved nor allowed :) .

Anyway, here are a couple of pix of the carb set-up on the donor engine. It's also a Type 4, complete but with a questionable valve problem according to the P/O. I was able to get all of the linkage and tubes (I hope!) and air cleaner assembly to properly connect and hopefully balance these two carbs:

This is the right/passenger side. This is a Solex 32-34 PDSIT-3

Here is the Driver's (left) side. It's a PDSIT-2 and both were made in West Germany (remember that?!! 8) ) I hope to rebuild these at some point in the near future.

Tue Jan 08, 2013 4:09 pm

Well, after the holidays and my work load, I finally found some time to pursue this again, and apply some of the suggestions. There were a couple of surprises, one of which caused an order of gaskets, more on that later. :o

One of the neat little things that was unexpected was finding one of two idle mixture screws laying on top of the block, and so there was a big problem there. :!: I was using a shop vac to remove all the debris in the compartment, and was very lucky to have seen it before it got removed along with all the wasp nests, oak leaves and decomposed chocolate cake which I think was once the engine tin seal. :roll: Anyhow, the other idle screw was screwed all the way in, seated. Also, one of the two worn out distributors seemed problematic, but that has been rectified by using the lesser of two evils until I can afford a nice new one.

Both of the idle set screws are back where they belong, and set around 1 1/2 turns out, and I adjusted the idle. Using your suggestions, and refering to Bentley, the engine now hums right along! :D

Unfortunately, both screws are very loose. I was thinking they should actually have springs inside the barrel, with the screw passing through the inside of the coil. This would give it the pressure it needs to stay put. If this is not the case, how should I remedy the loose screws? They are both easily manipulated by light finger touch, so it is highly likely that they will vibrate out over a short period of time.

Anyone have an opinion, I'd like to hear from you. :D

Tue Jan 08, 2013 4:35 pm

Wasted youth/adulthood wrote: Unfortunately, both screws are very loose. I was thinking they should actually have springs inside the barrel, with the screw passing through the inside of the coil. This would give it the pressure it needs to stay put. If this is not the case, how should I remedy the loose screws? They are both easily manipulated by light finger touch, so it is highly likely that they will vibrate out over a short period of time.
This is for a DG series but does #58 & #59 look familiar?

Tue Jan 08, 2013 5:18 pm

Actually, 33, 33A and 34, 35 are a closer match. Note there are two of them on my carb, as in your exploded parts diagram. Also, equally important, I thought I had a DFEV but I have a 32/36 DFAV per stamping on base. I also see when those parts are referenced, they indicate thier names: "Primary and Secondary Idle Jet, gasket and holder."

Your contribution is very helpful. I see now that I am missing the gasket, but am a little suprised that there was no spring. Also, I thought the needle/screw was one piece, but it is actually two pieces. Perhaps that is so I could change needle jet sizes...?

I hope a replacement gasket will tighten up the jet/screw, but I am a little skeptical. Hopefully, this condition is not indicating exessive wear or abuse.

Tue Jan 08, 2013 5:36 pm

Maybe you need to pull out your camera for some pics, 33-35 are the slow running or idle jets and thier holders, they screw in tight and are not an adjustment. To adjust those you remove the holder and replace the jet in the end with the desired size, then screw it back in tight (well not so tight you jack up the threads but snug enough to not come loose by itself). #58/59 is the idle volume adjust screw that sticks out of the base flange.

I believe the difference between the A and E model is the way the primary shaft rotates (CW or CCW). I thought a DF was not progressive like the DG and both bores opened simutaniously but I've never fully grasped that Weber ID system.

Tue Jan 08, 2013 5:50 pm

That's interesting. I'll look into that, and crawl around in there to see if tweaking #58/59 makes a more significant change. When I replaced 33A and 33 (one of which was just laying around not participating), I assumed that was a key problem resolved. That, and I previously discovered a vacuum leak on the intake flange for cyls. 1&2. I was going to go into a little detail on that, but later. Perhaps repairing the vacuum leak did more for a steady idle then #33/33A, ya think?! :lol:

When I replaced then manipulated 33 and 33A, I felt it made a minor change in idle, thinking those were the idle settings that SG Kent and others were telling me about a couple of weeks ago. But, my ignorance of this carb directed me elsewhere, apparently. So, I will snug those down after I get gaskets for them somehow, then turn my attention to #58/59. I don't know if my camera will do well with a close up of those while on the engine, but I'll try. The railroad has me out of town again, so it will have to wait until tommorrow evening. Thanks again!

Tue Jan 08, 2013 6:01 pm

Here, this is about as close as I get with mine:

http://www.carburetion.com/diags/3236DFAVDiaginfo.asp

Under parts 14A and 15 (only one 15 is shown in the drawing), these are the two items that correlate with 33A, 33 on your drawing. I see that under this plan, no provision is made for a gasket on the screw. I suspect that simply tightening these snug should be sufficient. Also, under their table on this link (above) the jets can be ordered in varying sizes. Why would one do that? Altitude and fuel types/combinations? Performance? :?: