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Sat Jan 24, 2009 10:35 pm

I just rescued a 71 Super Beetle. Its a dual port 1600 and has a 043905205 SVDA distributor. It appears that someone replaced the carb with a H30/31 PICT. From what I have read this is not an ideal combo. It seems to run okay but is there any harm in running this combo? Could I expect a performance increase if I went to a 34 PICT?

Sat Jan 24, 2009 11:58 pm

Are there any issues now? I don't think you'll notice much of a performance increase if everything is running ok now. The combo is not ideal, but it can work.

Sun Jan 25, 2009 12:34 am

The 30/31 solex works best on the single port engines,,,which is was made for,,as a replacement for the 30 or 32 stock carb. The problem I see is not with the ignition. The distributor will get enough vacuum from the port on the side of the carb,,but the carb is limiting the air flow with its small venturi size. So, the 34 mm carb will always work better,,,,if you compare good carb to good carb.. Any messed up carb,,,forget it,,,it will never give you any good results.

If you feel like the performance is not the same as it was before you put on the carb or you don't have a way to compare it to the 34,,,I suggest you use some jet drills and go one to two sizes larger on the enrichment nozzle,,,the thing you see that squirts extra gasoline into the throttle plate area of the carb. That will give you slightly better response for a few seconds, when trying to pull out on a highway. Also,,,try switching the idle jets, front to rear as the one towards the rear of the car,,,towards the fan shroud,,,,is only size 50 and the forward one is size 65. Sometimes, switching the jets around to put the larger one in the rear area will improve the way these replacement carbs work,,,or drill out only the rear idle jet to two sizes larger,,again using the jet drill bits. If you don't have any,,,,check with any high performance VW place and I have bought them from Snap ON, or other tool supply trucks. They come in handy on all stock carbs,,,especially if you go with a tuned exhaust system.

The distributor works off vacuum.. Be sure your valve lash and timing is correct. -----George K. -----

Sun Jan 25, 2009 6:08 am

Is this a big can distributor? If not, then the 30/31 will not pull enough vacuum to give you full vacuum advance. One thing to think about if you are pondering a 34 PICt is where to get one. I would suggest a rebuilt from Keifernet.

Sun Jan 25, 2009 6:47 am

A few years ago I puts a 1600 in my while while I was building my 2180. It had a H30/31PICT and a OO9 distributor. I took the opportunity to try a few things and installed a 034 (SVDA) and a 019 mechanical. I found the 019 worked best and that the vacuum part of the 034 didn't work at all since the H30/31PCIT doesn't have enough vacuum for it.

1600DP w/ H30/31PICT and 034

1600DP w/ H30/31PICT and 019

I know what works because I tried it.

Sun Jan 25, 2009 12:43 pm

Someone is overlooking something here with regard to vacuum,,,saying the 30/31 does not pull enough vacuum.. Anytime, and this is just science for those that know physics, you decrease the diameter that you are pulling air through a tube, you increase the vacuum,,,for the same size engine. So, going from the 34 mm to the smaller 30/31 will cause more vacuum by the engine on the smaller carb. It does this because you are making the same amount of CFM the engine wants to go through a smaller venturi. This is why you have problems with too large of carb on an engine,,,you have messed up the vacuum flow. Now, that explained, one has to use an adapter under the base of the 30/31 carb. My educated guess is that someone is closing off all or part of the porting inside the carb,,that leads to the vacuum port on the side of the carb,,the one you attach the distributor vacuum hose on. If that is partially closed or blocked,,,then, yes,,,,,,you will have problems with not enough vacuum. If you notice on all the VW Stock distributors,,,,,VW used the SAME size vacuum hose on all numbers of vacuum advance distributors and for all years,,,that I recall.. So, if the theory is correct that one vacuum pot requires more vacuum than another,,,,VW would have had serious problems with their design.. This is not the problem. Any vacuum distributor will work off the same small port on the side of the carb,,,if the passages inside the carb going to the base are not blocked. Or, one other point,,,if your engine is low on compression,,,,,,lack of compression = lack of vacuum and that will also affect vacuum advance. Low or worn out rings will cause carbs to really mess up. It is all about air flow,,same thing for vacuum. Note to those that know. I refer to the small advance vacuum hose,,,not the ones used for retard functions. See, VW used larger port for retarding and larger hose,,,,to reduce the vacuum. Follows my theory, above.

Sun Jan 25, 2009 12:50 pm

The H30/31PICT works fine with the vacuum only 205L/M/T since they have large diameter vacuum canisters. But it does not work well with the small diameter canisters, specifically the 034 / 205zb.

I know that because I tried them and found it true.

Sun Jan 25, 2009 1:29 pm

Quote: Any vacuum distributor will work off the same small port on the side of the carb

Sorry - but no - that is not the case. There are some serious flaws in your logic, but it's not worth getting into. Bottom line is that certain carbs and distributors play better together. The biggy on the distributor (besides the mechanical advance portion, if it has one) is the vacuum can. There are big cans to work with low vacuum signal carbs and smaller ones to work with higher vacuum carbs. A new off the shelf SVDA works great with a 34 PICT, but doesnt not work with an H30/31. Does't matter if on a single port or a dual port and using adapter or not.

Glenn has summed this up pretty well already.

Sun Jan 25, 2009 1:46 pm

Thanks everyone for all the input. I just got the beetle so I'm trying to learn more about it. It seems to run fine with the 30/31 and vacuum advance distributor. If it's not a harm to the engine I'm going to leave it for a while while I go over other aspects of the car. Correct me if I'm wrong but the 034 is a SVDA distributor, so if its not geting enough vacuum it will still mechanically advance? Next oil change I'm going to hook it up to the fancy digital timing light I just bought and check things out.

One more thing since the 30/31 has a smaller venturi than the 34 is it safe to say its a restriction?

Sun Jan 25, 2009 1:48 pm

andk5591 wrote: Quote: Any vacuum distributor will work off the same small port on the side of the carb

Sorry - but no - that is not the case. There are some serious flaws in your logic, but it's not worth getting into. Bottom line is that certain carbs and distributors play better together. The biggy on the distributor (besides the mechanical advance portion, if it has one) is the vacuum can. There are big cans to work with low vacuum signal carbs and smaller ones to work with higher vacuum carbs. A new off the shelf SVDA works great with a 34 PICT, but doesnt not work with an H30/31. Does't matter if on a single port or a dual port and using adapter or not.

Glenn has summed this up pretty well already.

I agree...

I think Andy( glutamodo ) has already covered this subject in great detail as well :D :wink:

http://www.thesamba.com/vw/forum/viewtopic.php?t=185095

It has nothing to do with the size of the vacuum hose per se... but everything to do with the drilling's in the carb bodies and even variances in the throttle plate butterflies etc.

Sun Jan 25, 2009 1:53 pm

Pound wrote: Thanks everyone for all the input. I just got the beetle so I'm trying to learn more about it. It seems to run fine with the 30/31 and vacuum advance distributor. If it's not a harm to the engine I'm going to leave it for a while while I go over other aspects of the car. Correct me if I'm wrong but the 034 is a SVDA distributor, so if its not geting enough vacuum it will still mechanically advance? Next oil change I'm going to hook it up to the fancy digital timing light I just bought and check things out.

One more thing since the 30/31 has a smaller venturi than the 34 is it safe to say its a restriction?
The 034 is a SVDA (Single Vacuum Dual Advance) it has both vacuum and mechanical advance.

When testing distributors with a H30/31PICT, I borrowed a Solex 34PICT-3 and found it worked best with the 034. But I liked the H30/31PICT with a 019 best of all and most drivable.

Just my opinion.

Sun Jan 25, 2009 2:32 pm

Glenn, as far as mechanical advance only goes, can you tell us how the 019 differs from the 010 and 009?

As I said in our PM conversation, my 009 works ok with my H30/31 on my 1500 sp, but I get a bit of a flat spot when it's cold.

Sun Jan 25, 2009 2:50 pm

The curves are different.

For those that like graphs, here's one, but without actually trying them in the real world, it's impossible to know from a graph.

Sun Jan 25, 2009 3:15 pm

Has any looked with their own eyes at the port under the throttle plate on all these carbs? The location is about the same on all the various sized carbs and brands and the same size port and follows with me saying the vacuum port is the same size,,as it the hose and the inlet to the various vacuum pots.

Andy spent a lot of time showing the differences in various combinations on engines. The rate or speed in which the vcuum goes into play is based on how everything is working inside the engine,,,,,,,,,,,,and the last thing to consider is the carb ports. There is little to no connection between changes in the vacuum amount between carbs,,,only differences in the various engines. Try finding good vacuum readings on any engine with something other than a stock cam and when you open up any throttle on any carb driven engine,,,,,,,,,,,,,,,there is a big drop in the vacuum on the gauge, then it recovers,,once engine rpms is stable. This is why VW states the full advance needed to be set some degrees before TDC as at idle, there was too little vacuum to work the advance diaphragm. Also,,,the mechanical advance was needed to get the timing up to where VW wanted it as the vacuum , by itself was not good enough.

I don't think you are comparing apples to apples,,,,,,,,,,,,as from my eye view of the various carbs I looked at,,,,the ports are all the same,,,,,,,,,,meaning the vacuum will only differ due to engine combinations. So, I don't think the 30/31 carb is to blame for not having enough vacuum and that point cannot be debated. The carb is only a device with holes in it,,,,,,,,,,,,,other than the throttle plate moving and some slight movement of the float,,,,,,,,,,it does nothing mechanical. Gas flow into the engine is the product of too many factors to discuss in this forum post. And, that also applies to vacuum. You cannot reasonably say that the vacuum of the 30/31 carb is too low. That statement, in itself,,,,,,,,,,,does not make sense.

----George K. -----

Sun Jan 25, 2009 7:14 pm

Get a vac gauge and verify it yourself. I did, Andy is correct.

Sun Jan 25, 2009 8:45 pm

Thanks guys for a great thread. It was a great service to a newby as well as to me. It gives answers as to what to do with the two 1600 single port engines I received on my latest cars because some pos (there are 2 ways to interpret those initials) hi-graded the dual port engines out of them.

One is a 72 bug with a 1500 or 1600 sp engine with Brosol 30/31 PICT carb and the 009 dizzy I stuck in it to get it running after the 049 dizzy with an Empi Compufire electronic ignition would barely work. It runs great up to about 4000 rpm and then "runs out of steam". My guess is that is was rebuilt with an aftermarket cam, and is woefully undercarbureted. Plans for it are a pair of Weber 34ICTs (if I can find single port manifolds) or a Zenith 32NDIX 2 bbl carb (which is a carb I really love, due to my Porsche days).

The other car is a 71 Ghia with a 1970 1600 sp engine with a Solex 30PICT-3 and and 009 dizzy. I have had it running only once, which was halted by a small engine fire when the fuel pump hose pipe came out. Said fuel pump is now in trash after being beaten by a hammer!

From previous forum readings (which got confusing at times) I had decided that the aftermarket SVDA dizzy wasn't going to work with these 30-size carbs due to vacuum mismatch, and only German 009 centrifugals should be considered due to quality control. I was trying to determine if the VW 023 170 034 (aka 043 905 205 ?) dizzy is an SVDA that would work with the carbs I have (This thread answered that it is indeed an SVDA -thanks).

Thanks to earlier postings on this thread I see my best dizzy choice for these two engines as being the German 009, with the 019 that Glenn recommends, or the vacuum only 205L, M or T dizzys as good alternates. If I go with the Zenith32NDIX it would seem the 019 would be the best choice. With the dual Weber 34ICTs, would the 034 svda work best? Am I on the right track? Comments please.

Mon Feb 06, 2017 12:57 pm

The SVDA distributors ARE NOT COMPATIBLE with the 30/31 carb! I learned that the hard way. Websites like CIP and Pertronix say the SVDA is compatible with all engines, but that is WRONG. The 30/31 carb was designed for single port engines. BUT, the SVDA distributors are only compatible with the carbs designed for dual port engines. The SVDA will fit in the engine, but won't operate correctly. The problem is the sensitivity of the vacuum advance can:

The SVDA was originally designed to be installed on DUAL PORT engines. The carbs that go on the DP cars produce a strong vacuum signal (200mmHg), and the vacuum cans on SVDAs are calibrated to operate at those pressures.

Sadly, the H30/31 PICT carb (and all SP compatible carbs) produce HALF that vacuum signal (100mmHg). Because of this, the vacuum can on an SVDA will not get a strong enough signal to activate soon enough, and the engine timing will not advance early enough.

The result: Jerking and thrashing at takeoff, and when encountering hills.

THE SVDA DISTRIBUTORS, AND H30/31 CARBS, ARE NOT COMPATIBLE. Don't waste your money.

Mon Feb 06, 2017 1:04 pm

The SVDA distributors ARE NOT COMPATIBLE with the 30/31 carb! I learned that the hard way. Websites like CIP and Pertronix say the SVDA is compatible with all engines, but that is WRONG. The SVDA will fit in the engine, but won't operate correctly. The problem is the sensitivity of the vacuum advance can:

The SVDA was originally designed to be installed on DUAL PORT engines. The carbs that go on the DP cars produce a strong vacuum signal (200mmHg), and the vacuum can is calibrated to operate at those pressures.

Sadly, the H30/31 PICT carb (and all SP compatible carbs) produce HALF that vacuum signal (100mmHg). Because of this, the vacuum can does not get a strong enough signal to activate soon enough, and the engine timing does not advance..

The result: Jerking and thrashing at takeoff, and when encountering hills.

THE SVDA DISTRIBUTORS, AND H30/31 CARBS, ARE NOT COMPATIBLE.

Mon Feb 06, 2017 1:05 pm

Totally not compatible! And my post where I laid this information out, was from over 10 friggin' years ago! I can't tell you how much it annoys me when I see "claims" of the H30/31PICT being "compatible" with SVDA distributors... ](*,)

Mon Feb 06, 2017 1:32 pm

I have had my Solex 30/31PICT on my 1600 DP engine (using adapter) with German 009 for a decade in the past, and just recently again on my rebuilt 1600 DP, seems to be fine for me.