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dcnjoe60
Samba Member
Joined: March 26, 2008
Posts: 434
Location: Missouri
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 Posted: Fri Feb 18, 2011 3:49 pm Post subject: OMG! 34PICT-3 |
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OMG! I've been struggling with my 34Pict-3 and an SVDA for months now. It ran okay, but not good. I did the rivet in the throttle plate (flange number on carb was 377-1).
Thirty minutes of work and it is like a brand new car! I had the carb previously set the best I could, but after this change, I had to significantly readjust (which makes sense, I plugged a whopping hole in the throttle plate).
To think I was seriously thinking of replacing the whole carb and for about 10 cents (if even that) it is now simply amazing.
I do have one question. The hole in the throttle plate was 5/32". The pop-rivet I used was 1/8". The 5/32 just would not go into the hole. Will that pose future problems (like the rivet wearing out and falling into the engine)?
I can honestly recommend this simple procedure to anybody who has a 34PICT-3 that was made for a DVDA and is trying to run it on an SVDA.
Thank you, Samba. |
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clarkbre
Samba Member
Joined: June 20, 2004
Posts: 1107
Location: Everett, WA
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| Posted: Fri Feb 18, 2011 4:14 pm Post subject: |
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| Isn’t the rivet just a piss-poor fix for when you’re running a 009? All things considered, and functioning correctly, the SVDA should be a very good match to that carb without riveting the throttle plate. |
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dcnjoe60
Samba Member
Joined: March 26, 2008
Posts: 434
Location: Missouri
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| Posted: Fri Feb 18, 2011 4:25 pm Post subject: |
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| clarkbre wrote: |
| Isn’t the rivet just a piss-poor fix for when you’re running a 009? All things considered, and functioning correctly, the SVDA should be a very good match to that carb without riveting the throttle plate. |
There are two versions of the 34Pict-3 one for SVDAs and the other for DVDAs. The difference is the hole in the throttle plate is 5/32" for the DVDA version and 1/8" for the SVDA.
A 34PICT-3 for a DVDA runs like crap with a SVDA, at least that has been my experience. It is my understanding that the larger hole changes the vacuum signal and therefore, the SVDA doesn't advance like you would think (it acts much like an 009).
Plugging the whole is not as good as having the correct throttle plate and some people solder the hole and drill the correct one. But the rivet works wonders.
Even though the hole seems just slightly larger, it actually lets in 56% more air. That extra air evidently acts like a huge leak.
After plugging the hole, I could dial in the DVDA version of the 34PICT-3 with no problems whatsoever. |
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Joey
Samba Member
Joined: August 12, 2005
Posts: 5366
Location: Nova Scotia - Canada
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| Posted: Sat Feb 19, 2011 6:39 am Post subject: |
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Good info. I didn't know there were two versions of the 34 Pict-3. Makes sense though.
_________________
Joey
‘60 Kombi - '74 Bus - '79 Panel - '65 Beetle |
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68IHscout
Samba Member
Joined: March 10, 2010
Posts: 3122
Location: santa ana ca
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| Posted: Mon Mar 28, 2011 8:14 pm Post subject: |
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| So who sells the correct throtle plate to run svda with the 34 pict 3 |
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glutamodo 
The Android
Joined: July 13, 2004
Posts: 26323
Location: Douglas, WY
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| Posted: Mon Mar 28, 2011 8:23 pm Post subject: |
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No one does, as far as I've ever seen. If you need to go smaller, you can always just solder it up and redrill it, but the pop-rivet usually does the trick.
And that hole in the throttle plate is not the only difference between SVDA and DVDA carbs. If it was, VW would not have issued a boatload of different "modification state" numbers over the years. There are differences in placement of the hole(s) for the lower advance signal. (and many different combinations of jet sizes)
Check out this thread of mine for some more info:
http://www.thesamba.com/vw/forum/viewtopic.php?t=185095
And aftermarket carbs, are usually set up for SVDA, despite the fact they have a fitting for a DVDA retard line... |
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JGax
Samba Member
Joined: March 01, 2011
Posts: 28
Location: Mexicali, Mexico
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| Posted: Tue Mar 29, 2011 7:46 am Post subject: |
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| Quote: |
| Thirty minutes of work and it is like a brand new car! |
Hi there.
What you get when reduce the zise on throttle hole is more vaccum throug the idle circuit that mean more gas, obvious, so the only thing I see here is that was much easy to adjust the mixture on the carb and make it more stable just at idle.
SVDA or DVDA dist is not the issue here, after you push the accel pedal the vacum signal is the same than with or without the rivet.
BTW, I glad to hear you have solved the issue |
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68IHscout
Samba Member
Joined: March 10, 2010
Posts: 3122
Location: santa ana ca
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| Posted: Tue Mar 29, 2011 8:42 am Post subject: |
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| Well I'm confused now, I have a h30/31 now with svda , so other than pop ribet what other changes do I need to do 74sb sp |
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JGax
Samba Member
Joined: March 01, 2011
Posts: 28
Location: Mexicali, Mexico
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| Posted: Tue Mar 29, 2011 9:24 am Post subject: |
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| Quote: |
| Well I'm confused now, I have a h30/31 now with svda |
I suggest to open a new thread with your issues.
Any way if you want, do right here.
Need more datails on your issues. |
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dcnjoe60
Samba Member
Joined: March 26, 2008
Posts: 434
Location: Missouri
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| Posted: Tue Mar 29, 2011 10:08 am Post subject: |
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| 68IHscout wrote: |
| Well I'm confused now, I have a h30/31 now with svda , so other than pop ribet what other changes do I need to do 74sb sp |
H30/31 shouldn't need a pop rivet, only a 34pict3 does. |
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glutamodo
The Android
Joined: July 13, 2004
Posts: 26323
Location: Douglas, WY
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| Posted: Tue Mar 29, 2011 11:47 am Post subject: |
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| 68IHscout wrote: |
| Well I'm confused now, I have a h30/31 now with svda , so other than pop ribet what other changes do I need to do 74sb sp |
I don't know exactly what AC.net does when they modify the ones they sell as being set up for SVDA. It may just be they plug off the upper advance fitting, although when I played with that myself I still don't think the vacuum signal was quite what it should have been for an SVDA distributor. If your carb is unmodified, the vacuum signature will be all wrong for the SVDA though.
I already posted this link once, here it is again:
http://www.thesamba.com/vw/forum/viewtopic.php?t=185095 |
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68IHscout
Samba Member
Joined: March 10, 2010
Posts: 3122
Location: santa ana ca
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| Posted: Tue Mar 29, 2011 12:11 pm Post subject: |
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| dcnjoe60 wrote: |
| 68IHscout wrote: |
| Well I'm confused now, I have a h30/31 now with svda , so other than pop ribet what other changes do I need to do 74sb sp |
H30/31 shouldn't need a pop rivet, only a 34pict3 does. |
I should have been more specific.....I'm replacing my 30 to a 34pict3 ,from what I understand ill get more benefit from my svda. 34pict3 combo....but I'm reading diferent posts some say it will work some say it needs to me modified, so I'm not quite sure if its going to work or not. |
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dcnjoe60
Samba Member
Joined: March 26, 2008
Posts: 434
Location: Missouri
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| Posted: Tue Mar 29, 2011 12:29 pm Post subject: |
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| 68IHscout wrote: |
| dcnjoe60 wrote: |
| 68IHscout wrote: |
| Well I'm confused now, I have a h30/31 now with svda , so other than pop ribet what other changes do I need to do 74sb sp |
H30/31 shouldn't need a pop rivet, only a 34pict3 does. |
I should have been more specific.....I'm replacing my 30 to a 34pict3 ,from what I understand ill get more benefit from my svda. 34pict3 combo....but I'm reading diferent posts some say it will work some say it needs to me modified, so I'm not quite sure if its going to work or not. |
If your 34pict3 is one of the brand new ones, it does not need the pop rivet. If is is an older Solex, it should have a number on the bottom left flange (left being the distributor side of the car). Post that flange number and I, or someone else, can look up whether that carb was designed for SVDA or DVDA distributors. Only those designed for DVDA need the rivet. |
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68IHscout
Samba Member
Joined: March 10, 2010
Posts: 3122
Location: santa ana ca
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| Posted: Tue Mar 29, 2011 12:39 pm Post subject: |
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| Here is the numbers vw355_2 and b3 072. Thanks for you're help |
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dcnjoe60
Samba Member
Joined: March 26, 2008
Posts: 434
Location: Missouri
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| Posted: Tue Mar 29, 2011 1:06 pm Post subject: |
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| 68IHscout wrote: |
| Here is the numbers vw355_2 and b3 072. Thanks for you're help |
That carb was designed to work with a 113905205AL distributor which is SVDA. You don't need the pop rivet.
Joe |
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68IHscout
Samba Member
Joined: March 10, 2010
Posts: 3122
Location: santa ana ca
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| Posted: Tue Mar 29, 2011 2:25 pm Post subject: |
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| dcnjoe60 wrote: |
| 68IHscout wrote: |
| Here is the numbers vw355_2 and b3 072. Thanks for you're help |
That carb was designed to work with a 113905205AL distributor which is SVDA. You don't need the pop rivet.
Joe |
thank you very much. Joe I apreciate the help! |
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Boble
Samba Member
Joined: November 13, 2005
Posts: 744
Location: Oslo, Norway
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| Posted: Tue Mar 29, 2011 2:30 pm Post subject: |
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I have struggled a lot with 34-PICT 3 carburators (1600DP, SVDA), especially with getting consistent idling in all types of humidity and temperatures. I found that it often died on me when the engine is half warm in cold, rainy days. Engine stopping at traffic lights drove me crazy...
My problems ended: I soldered the hole completely shut. After that, idling has been perfect!
How come? The Solex people definitely put the hole in there for a good reason, so why block it? My theory is this:
On a brand new carb, the trottle plate fits tightly in the main bore. However, after 35-40 years of use, the soft aluminum and the brass trottle plate is worn (hold the carb up to a lamp, and you'll see what I mean). Air leaks. By blocking the hole, you get a more correct (richer) mixture.
Makes sense? I don't know, but my engine idles great. Worth a try... |
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dcnjoe60
Samba Member
Joined: March 26, 2008
Posts: 434
Location: Missouri
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| Posted: Tue Mar 29, 2011 2:54 pm Post subject: |
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| Boble wrote: |
I have struggled a lot with 34-PICT 3 carburators (1600DP, SVDA), especially with getting consistent idling in all types of humidity and temperatures. I found that it often died on me when the engine is half warm in cold, rainy days. Engine stopping at traffic lights drove me crazy...
My problems ended: I soldered the hole completely shut. After that, idling has been perfect!
How come? The Solex people definitely put the hole in there for a good reason, so why block it? My theory is this:
On a brand new carb, the trottle plate fits tightly in the main bore. However, after 35-40 years of use, the soft aluminum and the brass trottle plate is worn (hold the carb up to a lamp, and you'll see what I mean). Air leaks. By blocking the hole, you get a more correct (richer) mixture.
Makes sense? I don't know, but my engine idles great. Worth a try... |
It does make sense, but it's not the reason for the hole or why plugging it works. A 34pict3 will idle just fine with an 009 distributor (but is not a good combination because of the inherent flat spot with such a setup). The problem is with a vacuum advanced distributor. The hole in the throttle plate changes the vacuum signal going to the distributor.
There are two different sized holes. For SVDA distributors it is 1/8" for DVDA distributors (those with advance and retard) it is 5/32". The retard wouldn't work as desired without the larger hole. However, a SVDA doesn't work correctly with the larger hole.
There are other differences between the carbs than just the hole size. The size and location of various passages change. However, none of these have as big an impact than the size of the hole.
Plugging the hole doesn't actually richen the mixture because of the way the air mixture is set on the 34pict3. (It will richen it if you don't readjust it after plugging the hole, however). It simply changes the vacuum signature for the distributor. It turns out that SVDAs didn't need the hole at all. However, they were not the only distributor available at the time nor the only application for the 34pict3. As such, the hole was added, since having it also did not adversely impact the 034 distributor designed to use it. |
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glutamodo
The Android
Joined: July 13, 2004
Posts: 26323
Location: Douglas, WY
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| Posted: Tue Mar 29, 2011 4:44 pm Post subject: |
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| dcnjoe60 wrote: |
| The hole in the throttle plate changes the vacuum signal going to the distributor.. |
Actually, I don't think that the reason for that hole to be larger on DVDA. The reason it's larger on those is to let more air past the closed throttle plate so that the engine will be able to idle better with the timig way back at 5ATDC. With SVDA the timing at idle is 12 degrees advanced, and that bumps the engine speed up considerably. Having a smaller hole on those makes it idle lower - and in both cases it allows the factory volume and air bypass screws to adjust well. When you mismatch those you often find that you have to either put your air bypass (idle speed) screw all the way down or all the way out to compensate, and even then you might not be able to get your idle speed set right.
-Andy |
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Bug Owner Again
Samba Member
Joined: March 12, 2011
Posts: 98
Location: MD
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| Posted: Tue Mar 29, 2011 6:01 pm Post subject: |
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| dcnjoe60 wrote: |
| 68IHscout wrote: |
| Here is the numbers vw355_2 and b3 072. Thanks for you're help |
That carb was designed to work with a 113905205AL distributor which is SVDA. You don't need the pop rivet.
Joe |
my Carb is a 34 PICT -3 Bocar 113129021P and I also have a 009 distributor. What is the best set up with my car? will my carb benefit with the rivet? I just bought the bug and rebuilt the carb and I am having trouble adjust my carb as well. |
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