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Discussion Starter · #61 ·
I think these links got confused along the way...
I beleive this is the link he is refering too.
http://www.jeepforum.com/forum/f8/we...-258-a-631105/
Yes they did and I didn't catch it the second go-around. Of course, I didn't expect the link to take us back to where we currently were either. What the... was there some thread editing going on that we didn't catch?

Either way, :nono::nono::nono: on the 34 toooo rich thread.

Shawn
 

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OK, ok, somethings amiss with my link! The thread I'm trying to link ya'all to is a huge, detailed write up on the Weber 34 too rich condition, what size jets to get for both run and idle, their part numbers (since Weber doesn't support the 34 anymore) and other info on the electric choke, mixture settings, fuel regulator, etc, etc, do the Nutter, etc, etc.
Again, I apologize for the crappy link - dunno why it's pasting something different than what I copy...
I spent all summer F-ing with this Weber 34 I inherited and that thread was a big help. Had to get the vac info elsewhere but I finally drove my Jeep today for the first time in 4 months.
Thanks for holding my hand there fellow BLS fan...
 

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I think he was asking if this is the proper thread which one should use for the set up and tuning of a Weber. So if that were the case the answer would be yes. However he should be aware that his carb is linked to Weber by sticker only. It is what it is, a 34DGEC also known as I believe it to be the Solex 34TEIE but in desgise...it is a met at the wharf thing going on with that.

IMHO all but the design and materials quality, the choke linkage, the screw settings, jets sizing and its reliance added to the loss of having skilled Redline tech support would be the same as a Weber. It seems that the screw settings are rather different because in helping others dial it in we've found that the "S" ported nipple is in fact in various positions...ranging from 1 to 4 1/2 turns in, with that carbs venturis being smaller while the bore is larger than either of these Webers that are the on topic/discussion of this thread, the use of smaller jets are beneficial. However not anywhere near as small at that previous thread suggests. A range that seems to fit well in that DGEC is within 5-10% smaller than the sizes discussed here as compared to those that seem to work best in the 32/36DGV series Weber.
 

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I think he was asking if this is the proper thread which one should use to for set up and tuning a Weber. So if that were the case the answer would be yes. However he should be aware that his carb is linked to Weber by sticker only. It is what it is, a 34DGEC also known as I believe it to be the Solex 34TEIE but in desgise...it is a met at the wharf thing going on with that.

IMHO all but the quality, the choke linkage, the screw settings, jets sizing and its reliance added to the loss of having skilled Redline tech support would be the same as a Weber. It seems that the screw settings are rather different because in helping others dial it in we've found that the "S" ported nipple is in fact in various positions...ranging from 1 to 4 1/2 turns in, with that carbs venturis being smaller while the bore is larger than either of these Webers that are the on topic/discussion of this thread, the use of smaller jets are beneficial. However not anywhere near as small at that previous thread suggests. A range that seems to fit well in that DGEC is within 5-10% smaller than the sizes discussed here as compared to those that seem to work best in the 32/36DGV series Weber.
I see with Freds old thread that he claims all Webers are the same, which is very close to being true.. The problem with this statment is he is "selling" us that this Solex 34TEIE that is imaculatley conceived on the warf and made into a Weber. This 34-DGEC is not a Weber, it is a Solex 34TEIE and does not tune as the real Webers tune. As clearly noted by Mcmud the exposed enrichening holes vary considerably affecting the idle speed settings. This also determines a rich or lean idle by having these enrichening holes exposed or not exposed, then changing an idle jet to compensate for this extra fuel from throttle plate position.
I just don't like this "bait and switch" at the warf and the deception that it implys and infers. An Opel made in Germany shouldn't be sold as a Cadillac in the USA because GM owns both companies.
 

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Discussion Starter · #66 ·
DrivinCat,

You're new here (Welcome! btw) so this is a freebie. "Weber runs toooo rich Tune (toon) Thread 34 blah blah blah" being mentioned, especially in a good way =



Shawn
 

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Discussion Starter · #68 ·
Are we going to jump to main circuit soon?
Jorge.
Well I decided that we just can't jump into the mains until we've had all the fun we could possibly have with the progression circuit; fully milking them for all they're worth, so here we go.

As good as idle jet changes based on mixture screw settings can be, if you're 95% nuts and 100% committed to getting every bit of mileage and performance out of a Weber, there's still some more fun that can be had.

For instance, if you have a synchronous 38 and you pay real careful attention to detail of the linkage geometry on both the carb and the throttle linkage, plus careful adjustment of the sector gears, you can get both throttle plates to close off to this position and move in perfect harmony with each other, returning to this exact position each time. You shouldn't have an issue but mine was stubborn.


Then you can drill the pressed idle air bleeds out and tap them for threaded air bleeds.


Once the passages have been thoroughly cleaned and inspected, the new idle air bleeds can be threaded in.


Now the door is wide open to fine-tune the fuel curve of the progression circuit with various idle air bleed sizes in addition to all of the idle jet sizes. Look at all of that adjustability.


With the throttle plates closed off per the first photo, like they honestly should be so that no fuel is allowed to flow from the progression hole during idle, should a higher idle speed be desired, little holes can be drilled in the throttle plates. This will bring the idle speed up a touch but, more importantly, will also serve to counter the richness of the larger first progression hole.


Don't go hoggin out your passages and throttle plates just yet, I've done this sort of thing before and this is my madness! This also isn't something a guy should do without an air/fuel monitor. These little tweeks go along way to stretching out the mileage and they give you the ability to tune out lean holes or rich peaks, should you have any.

Shawn
 

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Well I decided that we just can't jump into the mains until we've had all the fun we could possibly have with the progression circuit; fully milking them for all they're worth, so here we go.

As good as idle jet changes based on mixture screw settings can be, if you're 95% nuts and 100% committed to getting every bit of mileage and performance out of a Weber, there's still some more fun that can be had.

For instance, if you have a synchronous 38 and you pay real careful attention to detail of the linkage geometry on both the carb and the throttle linkage, plus careful adjustment of the sector gears, you can get both throttle plates to close off to this position and move in perfect harmony with each other, returning to this exact position each time. You shouldn't have an issue but mine was stubborn.


Then you can drill the pressed idle air bleeds out and tap them for threaded air bleeds.


Once the passages have been thoroughly cleaned and inspected, the new idle air bleeds can be threaded in.


Now the door is wide open to fine-tune the fuel curve of the progression circuit with various idle air bleed sizes in addition to all of the idle jet sizes. Look at all of that adjustability.


With the throttle plates closed off per the first photo, like they honestly should be so that no fuel is allowed to flow from the progression hole during idle, should a higher idle speed be desired, little holes can be drilled in the throttle plates. This will bring the idle speed up a touch but, more importantly, will also serve to counter the richness of the larger first progression hole.


Don't go hoggin out your passages and throttle plates just yet, I've done this sort of thing before and this is my madness! This also isn't something a guy should do without an air/fuel monitor. These little tweeks go along way to stretching out the mileage and they give you the ability to tune out lean holes or rich peaks, should you have any.

Shawn
Interesting information Shawn. Were you able to come up with anything specific as to mileage numbers? I was getting 18 with 45 jets, but still had my mixture screws too far out, so I went up to 60's and lost considerable mileage, but at the same time that weber runs better than it ever has.
 

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Discussion Starter · #70 ·
Interesting information Shawn. Were you able to come up with anything specific as to mileage numbers? I was getting 18 with 45 jets, but still had my mixture screws too far out, so I went up to 60's and lost considerable mileage, but at the same time that weber runs better than it ever has.
No doubt the 60s are powerful jets, they're just pig rich down low.

I'm not using any screw settings anymore, I'm simply tuning the fuel curve of each circuit under actual driving conditions so I'm not even sure where the screws are at this point. :shhh:

The progression curve was basically upside down delivering a rich mixture just off idle with barely any load and getting leaner with more throttle input and increasing load. This is no doubt due to the first progression hole being nearly twice the size of the others. The mods I've done thus far have corrected the pig-rich entry and now I just need to settle into a final idle air bleed size to control the mixture a little higher up in the rpm range. It'll likely end up being a .065 with the 45 idle jets.

I don't have any mileage numbers as of yet but I will surely post up when I do. Just looking at the a/f numbers recently, it has the potential to deliver some good mileage improvments. It sounds and feels very crisp and responsive.

Shawn

P.s. For anyone reading this who may be considering a Weber 38, this kind of stuff is not neccessary to make it run. As Jorge stated earlier, the 38 is about as plun-n-play of a carb as you can get. I'm just half crazy and have other plans for this carb which will require this sort of adjustability. I'm just throwing out some of the stuff that can be done.
 

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Cool, pulling and tapping the idle air bleeds. I use to just solder the bleeds and use some different drill sizes but I think replaceables are better.

I notice you have removable booster venturies. Are we going to get into what booster venturi is best? If I remember correctly, I had 3 different types for that carb. Some short, some long, some with the port flush with the walls of the booster....

Yes, I had a lot of Webers in my past life.. :) the only Weber I have now runs on propane...:D
 

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Discussion Starter · #72 ·
I notice you have removable booster venturies. Are we going to get into what booster venturi is best? If I remember correctly, I had 3 different types for that carb. Some short, some long, some with the port flush with the walls of the booster....
John,

The threaded inserts are quite handy. You can drill a run in what ever range you want, say 1.50mm to 1.85mm in .5mm steps and just start testing.

Those boosters sure take up a lot of space in there don't they. I've caught myself searching for boosters many times and haven't been able to find any online. I'm thinking a nice, annular discharge booster, hopefully with only one leg would be very sweet for tip-in atomization and overall low-speed performance.

I happen to know a knucklehead that'll try 'em if you know where to buy 'em. :thumbsup:

Shawn
 

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The best low speed (Low RPM) performance I saw was on carbs with dual boosters. Usually they ran dual boosters if they had to use a large throttle bore for top end performance. The signal at the port was great and responsive. Of course there was a lot of metal in the way for any WOT performance. You saw this on a lot of Jap carbs.

Annular ports like on some of the the Holley 500 2bbl are great only for WOT performance. The theory was many little holes would atomize the gas better but in practice it took a strong signal to draw out the fuel in the first place.

I remember buying tubing and making some of our own boosters to use on some old Webers out of Fiats and Ford Capris. We were kids then and didn't really know what we were doing and if it didn't knock a second of our ET's the idea was a washout but now I wonder how it effected other things.

I remember putting baffels (baffles?) in the bottom of the fuel bowl to keep fuel from sloshing away from the jets in quick turns.
Still it seems like a good idea. Hmmm. I really need to get a Weber again to play with, too bad I sold my creat of carbs that I had collected. My 45DCOE is just a pencil holder now....
 

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Discussion Starter · #74 ·
I sure like the adjustability of the low-speed circuit with the threaded air bleeds. It's very easy to add or reduce the fuel delivery by a small amount and be able to basically split the difference between two different idle jets. While the difference was appreciable on the 38, I bet it would be much more pronounced and beneficial with the velocity-streched primary barrel of the 32/36.

What I'm really enjoying is the profound impact that the emulsion tubes have on low-speed mixture strength and the timing of the main circuits' activation. It's neat how the idle jet/low-speed air bleed combination along with careful emulsion tube selection can be made to overlap each others' delivery almost seamlessly and allow a smooth yet powerful midrange transition into the main circuit without an excessive light-operation mixture.


Shawn
 

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I sure like the adjustability of the low-speed circuit with the threaded air bleeds. It's very easy to add or reduce the fuel delivery by a small amount and be able to basically split the difference between two different idle jets. While the difference was appreciable on the 38, I bet it would be much more pronounced and beneficial with the velocity-streched primary barrel of the 32/36.

What I'm really enjoying is the profound impact that the emulsion tubes have on low-speed mixture strength and the timing of the main circuits' activation. It's neat how the idle jet/low-speed air bleed combination along with careful emulsion tube selection can be made to overlap each others' delivery almost seamlessly and allow a smooth yet powerful midrange transition into the main circuit without an excessive light-operation mixture.

Shawn
This is a very interesting and advanced experiment here. I have heard of drilling out the air bleed for usage at or above 6000 feet elevation. I believe the 38-DGES has a 1.90mm air hole and drilled to 2.00mm or 2.05mm helps allot for the Jeeps drivability at altitude. What material did you use and how did you thread the air bleed? Also, I know by reducing the size of the air bleed you would be able to use a smaller fuel jet keeping the "reasonably" same atomization and drivability and reduce the volume of fuel blowing out the exhaust. What sizes air bleed with what size fuel jet have you tried? What are your driving air fuel ratios, if you have them?
Shawn, thank you for sharing your information, I could see how you could easily ruin a perfectly good carburetor by not being careful.:highfive:
UPTILLNOW
 

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Discussion Starter · #76 ·
This is a very interesting and advanced experiment here. I have heard of drilling out the air bleed for usage at or above 6000 feet elevation. I believe the 38-DGES has a 1.90mm air hole and drilled to 2.00mm or 2.05mm helps allot for the Jeeps drivability at altitude. What material did you use and how did you thread the air bleed? Also, I know by reducing the size of the air bleed you would be able to use a smaller fuel jet keeping the "reasonably" same atomization and drivability and reduce the volume of fuel blowing out the exhaust. What sizes air bleed with what size fuel jet have you tried? What are your driving air fuel ratios, if you have them?
Shawn, thank you for sharing your information, I could see how you could easily ruin a perfectly good carburetor by not being careful.:highfive:
UPTILLNOW
It requires a 10/32 tap and the appropriate bit. I'm having a hard time finding the allen-headed, brass plugs but you can purchase a kit from Paul at www.performanceoriented.com. Mcmud found him several months ago and it turns out that he and I have a very similar approach to carburetors. He's a really cool guy and can put a kit together for you.

You're right, the 38 is supplied with 1.90mm air bleeds and I've been around the world with them. I've gone from 1.50 up to 1.90 in .5mm increments using a pair of 45 idle jets and I do like the way they're a little leaner on entry than the 50s and quite a bit better than anything larger than that.

With 1.2mm holes in the throttle plates, the 45/1.70 was perfect. The rich entry was leaned quite a bit with the holes without adversely affecting the entire progression. The idle just wasn't quite stable enough for me. I'm convinced that an engine with a performance cam, heads, intake etc would respond extremely well to that modification. It just wasn't quite right for a stocker so the holes were soldered up.

Personally, I liked the 45/1.80 or 1.85 combo with the F50 emulsion tube. It wasn't as rich on entry as the 50/1.90 combo, which would come in around 13:1 under the lightest of input, but held on to a decent mixture a little longer than a 45/1.90 set up.

I'm currently using a 45/1.90 which seems to tip in in the higher 14s afr but I've also been playing with the emulsion tubes. Here's a shot of an F50, which is installed from Weber, an F6 and an F7 on the right.


The pattern of large holes placed higher up on the tube of the F50 makes for a lean entry and then a large amount of air is let in once activated. The F6, center, is better but tips in quite early, followed by excessive leaning on fairly large throttle opening, and then a really powerful midrange. The F7 was even richer on entry but equally powerful.

Here's my modified F7, which, after six hours of modifying and testing, we can refer to as an F-THIS :shhh:


The upper holes with a 3/4 inch float drop seem to bleed off enough well depression at light throttle to allow a nice cruise on the progression circuit. When the throttle is opened quickly, the middle pattern is much more responsive than the F50 and seems to deliver a very strong mid-range punch, where the F50s always went lean, and the lower hole pattern seems to be holding the wide open throttle afr linear at about 12.6:1 up to redline using a 145 main jet, 175 air corrector combo.

I'm afraid I'm at the limits of testing accuracy with this tired old engine and without a controlled environment but this has quite a bit more mid (1,800 rpm) and upper-range power and response than the F50 and needs less jet to do it. The lean hole at large throttle opening experienced with the F50 is gone now and the mixture is more consistant. So far, so good...

Side note: I'm sure my piss-poor gears have exaggerated any lean entry that the F50 emulsion tubes may have had. A decent gear set or an automatic would likely rpm right over any leanness and you'd probably never know it was there.

Shawn
 

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Discussion Starter · #77 ·
Based on previous experiences and this most recent work, I'm going to offer up some broad generalizations while it's still fresh in my mind and wait for your feedback.

The activation point and also the mixture strength of the main circuit is controlled by the emulsion tube to a much greater extent than the main jet or air corrector. It also is the key to how well the main circuit responds to large throttle openings and overall mixture consistency, once activated.

The true mixture strength or sizing of the main jet is measured down lower in the rpm range (2,500 rpm) at WOT and is influenced to a lesser extent by the lower holes of the emulsion tube.

The WOT mixture at the top of the rpm range is most influenced by and adjusted with the air corrector.

Thoughts?


Shawn
 

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Here's my modified F7, which, after six hours of modifying and testing, we can refer to as an F-THIS :shhh:


Shawn
Shawn,
Thank you for your results from testing the idle air bleed sizes vs. idle fuel jet sizes within reasonable air/fuel ratios and reasonable sensing the power results. I like your results from the idle circuit to main circuit tip-in while changing to the F6 emulsion tube, this opens up an advanced tuning and new look in power vs. fuel usage. I have used the jetting that typically comes in the 38-DGES and adjusted (lowered) the float level (18mm) to delay the main circuit entry which also helped eliminate that transitional "excess" of fuel at the end of the idle circuit entering into the main circuit. 3/4" or .19mm seems like it is too low for a float level, I will try this also. The accelerator pump nozzle is also used as a "High Speed" enrichening device. I believe the 38-DGES comes with a .70mm accelerator pump nozzle size, by decreasing that size without sacrificing the needed fuel from the pump shot should also decrease that transitional air fuel ratio a little more. I am out on that F7 E-tube now called F-THIS.
So I am going to try this F6 e-tube and lowering and raising the float level for timing the main circuit entry. This is good stuff…. Thank you again for sharing this.
UPTILLNOW
 

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Discussion Starter · #79 ·
So I am going to try this F6 e-tube and lowering and raising the float level for timing the main circuit entry. This is good stuff…. Thank you again for sharing this.
UPTILLNOW
Yeah, I'd love to be able to tweak things and compare notes. Very cool! :highfive:

Shawn
 

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Since emulsion tubes hole and fuel levels are closely inter-related, Have you tried the engine at different angles one might find offroading? I confess that most of my Weber experiments have been done on flat surfaces at high Gee's but not starting from idle on the side of a hill. I remember it was easy to flood an engine in a high Gee turn with a Weber if the floats were mounted 90* from the way the carb was designed to work. It was always better to get the right manifold so the carb was mounted properly rather than adapting the carb to work with an OEM manifold if it meant mounting the carb wrong. I really like the Clifford manifolds that accept a number of different carbs.

You can't see the difference between those three emulsion tubes but some had various diameters also that would also effect the mixture. I remember chucking some e-tubes into an electric drill and reducing the diameters down to change the mixture.

You can see there are so many variables here a guy could go crazy modifying the carb to fit their engine.

One nice thing is that if you understand how a carb works, I mean really works, then this knowledge is also perfect if you ever go to FI and have to adjust the fuel tables. Every thing Shawn talks about how modifying the Weber to make his engine work would be invaluable if he ever went to FI. All the time you read about some FI conversion not working properly and looking for a new program or prom to get his engine to work right. So even though we are talking Webers here, this will apply to any fuel delivery unit you will ever work on.

One other thing I'd like to mention since this is a discussion on Webers is that what works on one 2 bbl manifold/exhaust setup might not work on a 79 or earlier manifold exhaust. You're going to have to learn how the carb works and what to look for to make your Weber work with your engine. Also consistency is important to testing as well as one change at a time. I had a hill that was a constant grade for about 1.5 miles that was a great chassis dyno. You could run your engine at a certain RPM to check performance on various modification.

Maybe we need a "how to check and verify changes" without access to a dyno at the end of this discussion. Plug cuts, stopwatches and mixture meters are all great to measure, I've even used a Gee meter when I had nothing else. (That's G as in gravity not G as in "Gee it works great. :) )
 
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