30/31 PICT or 34PICT-3?

aeromech · Posted: Fri Sep 23, 2011 5:40 pm Post subject: 30/31 PICT or 34PICT-3?

Guys,
I'm working on a dual port 1600 in a 1971 bus. Currently I have the 30/31 Solex soaking overnight and will rebuild it tomorrow. The carb has an adapter that lets it fit the intake manifold which was designed for the 34PICT-3. I also have several of the 34PICT-3 carbs in my stock. My question is should I reinstall the original carb after the rebuild or suggest to the owner that we change to the newer 34PICT-3? Seems to me that it would be simpler to just reinstall his 30/31 but if there is a power or reliability gain I might be able to talk him into the 34PICT-3.
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Randy in Maine · Posted: Fri Sep 23, 2011 5:47 pm Post subject:

What distributor are they running?

aeromech · Posted: Fri Sep 23, 2011 5:51 pm Post subject:

009
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
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Capable of leaping tall buildings in a single bound

Randy in Maine · Posted: Fri Sep 23, 2011 6:02 pm Post subject:

Probably the 30/31.

Desertbusman · Posted: Fri Sep 23, 2011 6:18 pm Post subject:

Clearly the 34PICT-3
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71 Superbug
71 Westy

aeromech · Posted: Fri Sep 23, 2011 6:43 pm Post subject:

Inquiring minds need to know. Why the disparity? Arguments are needed for your opinions.
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

Desertbusman · Posted: Fri Sep 23, 2011 7:10 pm Post subject:

Which one was specifically taylored for a 1600DP? Which one is larger for performance matching with the engine? Which one was no longer used when the DP came out? Which one fits the manifold? And a lot of people say the small carb isn't suitable for use with an 009.
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71 Westy

dti · Posted: Fri Sep 23, 2011 9:45 pm Post subject:

I have a 1600 dp engine in my '70, which came with an odd assortment of accessories: an H30/31 carb and the stock-for-1970 vacuum only distributor. Combined with the coked up manifold heat runners, it ran poorly and would stand on its nose when I gave it gas from a stop.

So, yeah: what DBM said...
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1970 Riviera 1600 DP
1996 Ducati 900 Monster

SGKent · Posted: Fri Sep 23, 2011 9:53 pm Post subject:

Gary I ran a 34-pict - 3 in a 1971 DP with an 009 for some time and never had any issues other than I wore the 009 out after about 100,000 miles. The stock carb will be better too especially if he decides to change to a DVDA like the original. I saw a NOS throttle positioner for sale yesterday so he could even go totally stock if he wanted. Not suggesting it just saying he could if he wanted.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

aeromech · Posted: Fri Sep 23, 2011 11:16 pm Post subject:

Great! This is good information. I'm especially interested in the throttle position parts that SgKent is referring to. So, if a person was to dyno an engine once with the 30/31 and then again with the 34 what would you expect to see?
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

SGKent · Posted: Fri Sep 23, 2011 11:18 pm Post subject:

Jody '71 · Posted: Sat Sep 24, 2011 5:10 am Post subject:

Gary,

I'd put a reliable 34-3 back in there jetted for Bus IMO. The 009 would be your decision and the owner's. Not sure if the 30-31 pulls the same vac as a 34-3 which is what you need if you use either an SVDA or a DVDA. Andy really knows his stuff when it comes to all of this. What would Glutamodo say???
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VWsArent4Hippies · Posted: Sat Sep 24, 2011 7:01 am Post subject:

I would not run the 009 with the 34. Especially if it's a newer Chinese 009. They seem to always have a flat spot when used together. Some people will put a pop rivet in the butterfly and that reduces the flat spot, but the 30/31 will always respond better with a 009

6sixTinBox · Posted: Sat Sep 24, 2011 7:46 am Post subject:

Volksdraggin · Posted: Sat Sep 24, 2011 8:02 am Post subject:

my 71 has a 1600 with a vac advance and 30-31 and it seems to work just fine. No flat spot, smooth power and just wooshes along.

aeromech · Posted: Sat Sep 24, 2011 10:15 am Post subject:

Well, I have to put the carb back together this morning so I might as well see how it runs on the bus. If I continue to have problems then I can always swap over the 34PICT-3 I have and try it. Thanks for all the comments and info brothers.
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

SGKent · Posted: Sat Sep 24, 2011 12:05 pm Post subject:

once again - the flat spot on an 009 is sticky weights, timed wrong or the idle set wrong. Weights and springs do not understand pauses. If you have a flat spot it is because you don't know how to tune an engine and I stand by that. Yes- there can be hundred, maybe thousands of people who do not know how to tune an engine. The 009 is not the cause of the problem. I read one article where it said there is a flat spot at 980 RPM. Well duh, the advance doesn't even start until there. Below that if the timing drifts it is dwell problems or too much play in the driven gear. I am just so tired of hearing about this flat earth 009 society myth. I do agree that the chinese copies of anything are usually inferior to the German ones and it scares me to heck that the new San Francisico Oakland Bay bridge is Chinese made and assembled here.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

aeromech · Posted: Sat Sep 24, 2011 12:58 pm Post subject:

it scares me to heck that the new San Francisco Oakland Bay bridge is Chinese made and assembled here.

There may be a good reason for that. As the years have passed this country has gone away from having the ability to manufacture large scale metal construction such as a bridge or the locks for the Panama Canal. Pittsburgh is a much different town than it was 40 years ago. They may call that progress but like you it scares me to think we have lost our manufacturing capacity and are left with cheap Chinese crap.

Pittsburgh then

Image may have been reduced in size. Click image to view fullscreen.

Pittsburgh now

China now

_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

Desertbusman · Posted: Sat Sep 24, 2011 4:08 pm Post subject:

ratherb-buggin · Posted: Fri Jun 28, 2019 7:37 am Post subject:


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