Comparing stock Solex carbs to each other, and to the H30/31

glutamodo · Posted: Tue Sep 28, 2010 12:34 pm Post subject:

5 after TDC is ONLY for DVDA distributors. If you have an SVDA that is totally wrong. Engine coes does not matter - timing is all based on what the distributor (together with the carb) gives you. If you have two vacuum lines coming from the distributor then it's a DVDA and yes the H30 will generate the "retard" signal for that distributor. However it won't generate the advance signal for it, as the DVDA needs a similar signal to an SVDA and the H30 only generates a much lower vacuum signal.

Orbison74 · Posted: Thu Sep 30, 2010 9:18 am Post subject:

Sounds like I'm really blowing it here. I wasnt sure of that. What kind of harm am I doing to my engine do you thing? I've put 15K on it since the rebuild and its been at 5ATDC for the last three years. I even drove 2100 miles in 36hrs across the country, not even a hickup. What do you think glutamodo? Should I retard it?
_________________
"If its not leaking, its out of oil."

73 Squareback Stock Fuel Injection

glutamodo · Posted: Thu Sep 30, 2010 10:00 am Post subject:

With your distributor at 5°ATDC - and if it's an SVDA it's actually running very retarded now. Those only give about 22 degrees centrifugal, subtract that 5°ATDC and you end with only 17 degrees total - and maybe a little bit more from vacuum advance but not much. SVDA advance is said to start at 55mmHg, but I think it's usually more like 80mmHg vacuum - and then pegs out at 200mmHg. The H30 will only give you the lower end of that range, so any vacuum advance will be minor. I'd have to know exactly what distributor it is and how it's hooked up, and check it with a timing light and all that though. It might be doing better than an armchair analysis predicts.

If it's running good, not overheating or the like, you're proabably not harming anything. I might just leave it be.

-Andy

Orbison74 · Posted: Thu Sep 30, 2010 10:21 am Post subject:

Thanks Andy, I'l grab the numbers to be sure. Come to think of it, it was in the shop that day I got the H30/31 and the guy timed it there... I havn't honestly checked it since. Judging by the fact that he spared the formalities with ordering the carb, maybe he saw I had it timed at 5ATDC and left it. Or set it correctly, I wont know untill I check. I'll report back when I find out.
_________________
"If its not leaking, its out of oil."

73 Squareback Stock Fuel Injection

SOUTHERN SWEEPING · Posted: Tue Dec 28, 2010 9:54 am Post subject: h30/31

i just bought a used h30/31 from las vegas and im at sea level in south carolina. my question is im having problems with it idling to high. when its adjusted it wont idle down without turning air screw till it runs ruff. should i change jet or jets ? or is sea level not the problem ?

sunbugone · Posted: Tue Dec 28, 2010 10:23 am Post subject:

what are your engine specs? Size etc...
_________________
1974 Sunbug
1974 Sunbug Convertible
1970 Westfalia

mondshine · Posted: Tue Dec 28, 2010 12:15 pm Post subject:

glutamodo-
It's interesting that this post re-surfaced today.
Just yesterday, I received a rebuilt 34PICT3 (410-1 with a single vacuum port) from Keith.
I got it to replace a Chinese 34PICT replicant that came with the car.
The engine runs great with the German Solex, but I did hit a small snag.
My distributor is a Mallory Unilite centrifugal/vacuum.
The Chinese carb produced enough vacuum at the side port to operate the vacuum advance on the Mallory distributor, which, according to my hand held MightyVac pump is about 10-12 in/hg. The Solex produces about half of that, enough for an SVDA, but not enough to budge the Mallory.

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

The advance drillings on my Solex look like this.
As much as I'd hate to FU a good carb, what diameter, or how much enlargement would it take to increase the vacuum at the side (and only) vacuum port on this 410-1?
I'm friends with a couple of dentists, but I've never asked to borrow their tools. Confused

Thanks, Mondshine

SOUTHERN SWEEPING · Posted: Tue Dec 28, 2010 12:22 pm Post subject:

1300 sp stock with electronic ign and 009 in buggy

sunbugone · Posted: Tue Dec 28, 2010 12:44 pm Post subject:

Is the carb new?? If it is used then it could have any jet sizes in it. the number stamped on the jet is not a reliable way to tell the jet sizes. I would think a 50 idle and 120-125 main would run on a 1300. Have you adjusted stock carbs before? If you have a jet gauge, check and see what you have in it now
_________________
1974 Sunbug
1974 Sunbug Convertible
1970 Westfalia

SOUTHERN SWEEPING · Posted: Tue Dec 28, 2010 1:04 pm Post subject:

carb is used it has 65 jet that is on angle and 50 jet straight on and the main is 125 . not sure about the 2 jets on outside which is which

sunbugone · Posted: Tue Dec 28, 2010 1:40 pm Post subject:

It should run with those jets, assuming those are the actual sizes. The idle speked should be the last thing you adjust. Check timing, screw the choke screw out and back in until it barely hits the bottom position of the cam (1/4 turn). I can usually get away with screwing the mixture screw (small one, driver side of carb) out about 2 1/2 rotations and the idle screw (big one, driver side) out 1 1/2-2 turns. Let the engine get fully warmed up, if it idles fast, let it be. Make sure the choke is fully off as well. Screw the mixture screw (small one) in SLOWLY until the engine starts to sputter then back out SLOWLY until it is at its fastest idle. Then adjust the big screw in to lower the idle. That should get you in the ballpark. If it doesn't run after that you may have other issues. Of all the h30\31 carbs I have messed with, none have given good results. The last one I had was a year old and the throttle shafts already needed rebushed
_________________
1974 Sunbug
1974 Sunbug Convertible
1970 Westfalia

SOUTHERN SWEEPING · Posted: Tue Dec 28, 2010 5:02 pm Post subject:

thanks will try and will look for a better carb .

glutamodo · Posted: Tue Dec 28, 2010 9:50 pm Post subject:

vw68autobug

HI

Very interesting info on the Carburetors and distributors here..
I have a Brasilian WEBER that looks a bit like a SOLEX carby..
it has the larger base , as My engine is a single port 1600 inlet manifold.
I can't sem to find any info about it.
whether its a good carburetor or Not.??
I was running it with a Bosch 009 but now have an SVDA from aircooled
and its now running great,,,

Lee in Australia
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Lee - 68AutoBug - helping keep air cooled Volkswagens alive in Australia -
http://photobucket.com/68autobug

glutamodo · Posted: Wed Jun 22, 2011 11:22 pm Post subject:

I've always avoided those Weber clones of VW carbs - If I had had one when I did these tests I would have included it. But I've only ever seen a couple of them ever. It must be a 30mm if it's on an SP manifold? I do have to wonder if you're getting a correct vacuum signal for an SVDA. But if it's running OK I'd say don't mess with success.

-Andy

vw68autobug · Posted: Thu Jun 23, 2011 5:26 am Post subject: Brasilian WEBER carburetor

HI
I had to slot the manifold to fit the carby, so it has larger throat than the original carburetor. [I left Gas in the original solex carby which turned to gunk and blocked up the accelerator pump valve]

No one seems to know anything about this Weber carburetor..
My Son found it in a box of parts, its like new.. when were they made and were they popular?? do they have a model number??

it has a choke cable setup and I don't have a cable going to it.. [as yet?]
but it starts OK and runs properly after a few minutes at 7C degrees..
and better at higher temperatures and settles down to a nice low idle with the engine warm... [it will get colder soon]
I did have a problem for a while with no vacuum advance.. but it has returned?? and advance to around 44 degrees when revving the engine with the vacuum connected.. depending on the timing naturally..
[it was only advancing to about 22 degrees at one stage]
My car is a 1600 SP autostick and its taken Me nearly 10 years to get it run perfectly with the autostick... [autostick small vacuum hose now in the correct LOW position]

I was wondering whether the vacuum signal was correct for the SVDA?
which is only a year old.. [on the car]
Do You think My weber is better than a Solex [SVDA] ??

many thanks for Your answers.

Lee in Australia 68autobug

_________________
Lee - 68AutoBug - helping keep air cooled Volkswagens alive in Australia -
http://photobucket.com/68autobug

Jeff54Griffin · Posted: Fri Jun 24, 2011 2:06 pm Post subject:

Are the jets from a Solex H34 fit in a Solex H30/31?
Thanks,
Jeff Griffin

glutamodo · Posted: Fri Jun 24, 2011 2:21 pm Post subject:

An H34? If you mean 34PICT-3... Yes, they'll bolt in a 34PICT-3, but I'd not change out the air correction jet - the ones on 34PICT carbs are smaller than the ones you see on the 30 series carbs.

The jets on those Weber carbs though, I'm sure those are not compatible.

Jeff54Griffin · Posted: Fri Jun 24, 2011 2:58 pm Post subject:

Thanks,
I find quite a few places that sell the jets (idle and main) for 34 pict-3's.
I will use them in my h30/31.
Jeff Griffin

NTM1971 · Samba Member Joined: March 22, 2010 Posts: 67

I have read opinions from the carb guru's here that the main reason why the 30 PICT 2 is not as popular of a carb is due to the fact the volume screw is factory set and is not adjustable. I came across a Solex 30 PICT 2 my local salvage yard with a base flange number of 126-4, and the volume screw is adjustable on it, like the 30 PICt 1's. Did they change this carb later on in production before they switched to the 30/3? The carb is in really good shape and I am thinking about putting in on the 1600 SP that I am in the process of putting together for my 69 Beetle.


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Comparing stock Solex carbs to each other, and to the H30/31
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