Flat spot with weber 32/36

My build specs: 1966 200 with 1975 250 head. Block is zeroed with 40 over, balanced. Head milled .060. All new caps, moly rings, bearings, Sealed Power dished pistons. Clay smith 264/264 110 cam. Adjustable rocker arm and hydraulic lifters. Static compression ratio 9.16:1. DGV 32/36 - Direct mount. DUI distributor Soon to be recurved). Rebuilt C4 automatic 3 speed with Transgo shift kit. Classic Inlines headers, arvinode dual exhaust. DUI distributor. Stock converter.

I have about 400 miles on the rebuild and trying to iron out all the little things. Today while doing some curve charting I pulled the plugs and checked gaps, they were gapped .035 by build shop, wear looked to be normal. I adjusted to .050 and took it for a drive.

Under moderate-heavy acceleration going uphill, at about 3/4 throttle I would hit a drastic flat spot. The motor felt like it would stall for a second, then would roar back after lifting foot of gas for a moment and reapplying. Before regapping plugs I did have a slight hesitation in acceleration at the same point, But today was drastically worse. It seems to be right about when the the progressive carburetor opens the second barrel. Other than this flat spot, the car is running really good. Under mild acceleration the flat spot is nonexistent.

I am running the mechanical fuel pump, I know this is inadequate for my set up hopefully I will have the electric installed soon(Airtex E8012S). I also understand this carb may be a little small for a healthy 200ci.

My question is would the increase in plug gap make the hesitation much worse?

Thanks in advance!

If the mixture is really lean at that point, increasing your plug gap could make it worse. The 32/36 is a little small for a healthy 200 with your specs, especially if it is still jetted for a 4 cylinder engine like these Webers came on. You need to either get an air/fuel sensor and see what your A/F ratios are, or search for the listing someone made of jet sizes and air bleed sizes that worked best for them. Seems everyone has to open these up quite a bit for best running with the 32/36.

Scott

Thanks for the reply Scott. Re jetting the carb is on the list after dizzy is recurved. Thanks again.

I agree with Mustang6 completely, rejetting is a must and what works for everyone else may not work for you and your setup. When you go to rejet make sure you get a good variety of jets ( mains, secondary and Air ). It has taken me quite a while to get mine tuned in but I think I have it pretty close now. When you do decide to jet use this as a guide:

Before tuning check the following:
• Is your engine sound and in a good state of tune? Problems caused by unrelated components are often blamed an carburetors.
• Are the float level and fuel pressure set to standard specifications for the carburetor being used?
GENERAL NOTE: Only change one type of component at a time. This will allow you to measure the effect of each change. Multiple component changes will only confuse you.
Prior to Starting engine
1. Remove air cleaner
2. Plug off open vacuum lines
3. Connect tachometer/vacuum gauge to engine
4. Idle speed screw should be set at one full turn in (clockwise) from point of initial contact with the throttle lever.
5. Idle volume screws should be set at one full turn out (counter-clockwise) from point of bottoming out (fully closed) Note: Do not over tighten during bottoming out or you may damage the screws.
6. Secondary throttle plates should be closed.
7. Check for fuel leaks.

Start Engine and Let Idle
• Immediately check for fuel leaks,
• If idle speed is too low to keep the engine running, turn the idle speed screw in an additional 1/2 turn. If the engine will still not idle, check for vacuum leaks.
• Make sure engine reaches normal operating temperature before proceeding.

1. Idle Circuit Adjustment
A. Starting with idle volume screws 1 full turn out from point of fully closed, adjust idle volume screws to obtain fastest and smoothest idle. To do this, slowly :turn each idle volume screw in (clockwise) until the engine speed drops noticeably. From this point, turn each screw out (counter-clockwise) to obtain maximum RPM.
B. Once adjusted stop engine and note the position of each idle volume screw. Do this by recording the number of turns in (clockwise) required to fully close each idle volume screw. All screws should require the same approximate number of turns. - Note: Do not over tighten. It is only necessary to seat each screw lightly.

C. Compare the number of turns in Step B, above, to the following chart and perform the required action.

Turns Out From Fully Closed - O - Fully closed but vehicle continues to run
Condition Indicated - Vacuum leak or idle speed screw turned turned in too far
Action Required - Ensure all vacuum ports/hoses are plugged off. Verify proper Idle speed screw adjustment. Correct and retest from A

Turns Out From Fully Closed - 1/2 or less turns out
Condition Indicated - Slightly rich
Action Required - Reduce idle fuel jets one size and retest from A

Turns Out From Fully Closed - 1/2 to 1 turn out
Condition Indicated - Correct setting
Action Required - Reset idle volume screws to 1 turn out and proceed to D

Turns Out From Fully Closed - 1 & 1/2 or more turns
Condition Indicated - Lean
Action Required - Increase idle fuel jet 2 sizes and retest from A. If condition does not improve re-check float and fuel pressure settings

When the correct idle fuel jets are installed, final idle volume screw adjustment will be between 1/2 to 1 turns out from fully closed. Idle speed will be sensitive to idle volume screw adjustments within this range. Note: Should idle volume screw adjustment be relatively insensitive check that the secondary throttle plates are not open too far.
D. Adjust idle speed screw to achieve desired idle speed. Final adjustment should be within 1/2 to 1-1/2 nuns in from initial contact. If idle speed screw is turned in more than 1 & 1/2 turns the throttle plates will uncover too much of the transition slot and the low speed circuit will begin to operate prematurely. This will cause an off-idle stumble. If you have an off-idle stumble, reset idle speed screw at one full turn in from initial contact and repeat the above procedure from step A.

2. Low Speed Circuit Adjustment
Note: Transition RPM values of 2500-2800 are approximate points of reference for circuit transition for medium weight vehicles. These values should be 3000-3300 RPM for lighter vehicles w/larger engines and 2000-2300 RPM for heavier vehicles w/smaller engines.
With the vehicle securely blocked to prevent movement and the transmission in neutral, slowly increase engine speed to transition RPM (do this slowly to minimize the effect of the accelerator pump circuit). Use the chart below to determine the action required.

Engine Behavior -Engine stutters or stumbles. Spits back through carburetor
Condition Indicated -The upper end of the low speed circuit is lean
Action Required -Decrease the idle air corrector jets by 2 sizes max and retest low speed circuit

Engine Behavior - Engine speed floats, sounds mushy or lazy. Black smoke from exhaust
Condition Indicated -The upper end of the low speed circuit is rich
Action Required - Increase the idle air corrector jets by 2 sizes max and retest the low speed circuit

Engine Behavior - Engine responds cleanly
Condition Indicated - Calibration is correct
Action Required - None, proceed to high speed circuit adjustment

3. High Speed Circuit Adjustment
Tuning of the high speed circuit should be done with the engine under a steady-state loaded condition on a chassis dyno or on an open track. An exhaust gas analyzer or plug checks used at the RPM ranges listed below will verify main fuel and air corrector jet sizes.
This procedure is laid out in two stages. The first is used to set the overall mixture as determined by the main fuel and main air corrector jets. The second will establish the proper entry point for the high speed circuit.
Note: Although these are given as separate procedures they should be done together at the same time. This is necessary because a change of either the main fuel or main air corrector jet size will have some effect on both mixture and entry point.

A. Mixture
1. Replace air filter and reconnect all hoses.
2. Using 1st or 2nd gear and moderate acceleration (manifold vacuum above 12.5") run the engine at or near maximum RPM and observe the engine behavior. Refer to the chart below and perform the appropriate action.

Engine Behavior - Runs rough, rattles, stumbles or spits back through carburetor
Condition Indicated - Lean
Action Required - Increase main fuel jets 2 sizes max, or decrease main air corrector jets 2 sizes max. Retest until condition corrected.

Engine Behavior -Engine pulls cleanly
Condition Indicated -Calibration is correct
Action Required - None, proceed to step B

Engine Behavior -Runs rough, seems lazy, black smoke from exhaust
Condition Indicated - Rich
Action Required -Decrease main fuel jets 2 sizes max, or increase main air corrector jets 2 sizes max. Retest until condition corrected.

B. Entry Point:
Using 3rd or top gear and moderate acceleration (manifold vacuum above 12.5") start at 3000 RPM and gradually increase to approximately 4500. Refer to the chart below and perform the appropriate action.

Engine Behavior -Stumbles and then recovers (slight hesitation) worsens with additional acceleration
Condition Indicated -High speed circuit entry point too early
Action Required - Increase main air corrector jets 2 sizes max to delay entry
Or Decrease main fuel jets 2 sizes max. Retest until condition corrected

Engine Behavior -Engine pulls cleanly
Condition Indicated -Calibration is correct
Action Required - None

Engine Behavior - Stumbles and then flattens out. Improves with acceleration
Condition Indicated - High speed circuit entry point too late
Action Required - Decrease main air corrector jets 2 sizes max to lower entry RPM,
Or Increase main fuel jets -2 sizes max. Retest until condition corrected

I am no Weber expert but I have gotten to know mine pretty well over the past few months and I think this will get you close to where you want to be.

Have fun and good luck with your project......

EightTrack

I've agonized over this from many cars I've worked on until I discovered the full workings of the Weber Emulsion tubes and Holley Weber 5200/5210/5220/6500/6510/6520 Well tubes.

The solution has been the United States Jeep, Opel GT, Datsun A series and MGB GT guys, who have had to deal with the missing info for years, and have really been an asset to everyone. Ford Six has been right up there, but the emulsion tube has been the missing link. But that's all fixed now.

In these three pages below, the MG B series guys discuss

1)the fuel pressure requirements,
2)float level,
3)the Emulsion tube type,

and what goes with what

An example is here http://www.mgexp.com/phorum/read.php?1,2372702,page=1

Despite all the awesome work people have done here at Ford Six, even journals of the jettings and all other details, the Emulsion/Well tube, float settings and accelerator pump is what really make the Weber 32/36 and Holley Weber 5200/5210/5220/6500/6510/6520 tick. Its been missing info, although it has been listed by a few stalwarts.

Problem is, no one knows what the correct six cylinder emulsion tube is to pick, and what you find on the modern and internet available Emulsion tubes don't relate to the 15 odd ball tubes in the factory Weber emulsion tube data. Since they don't cross over to those common popular reference sizes available in the US and United Kingdom, the Weber info is of not much use. And the Emulsion tubes sold in Australia aren't even on the list, nor are the excellent US Holley Weber 5200/5210/5220/6500/6510/6520 Well tubes.

The question is always Where do the common Weber F25, F50, F66, F78 and US Holley Weber 04. 05, 974, 975's rate and relate on the Lean to Rich scale compared to the not so common F2-F3-F6-F7-F8-F9-F15-F16-F20-F21-F24-F26-F33-F34-F35? .

The answer is that the lean to rich chart has to incorporate the common sub types (F3-F5-F6-F7-F25-F26-F50-F66-F78 of the Weber Chart, and not the wacko oddball 61450.xxx F13 that people get mixed up with from the early totally unrelated Weber DCD 28/36, or F71, F93,F110's that you see peddled elsewhere. UK choices include F8 as well, so F8 should be included.


Hence the valid jet set for Weber 32/36's and Holley 5200 and there offshoots are just 10, not 65. The 10 best are F3-F5-F6-F7-F8-F25-F26-F50-F66-F78.

The F5's, F6's, F50's, and F66's will get the job done. I've not used an F78 on a Weber 32/36 yet.

The neat thing is that the Weber 34 ICT and 34 ICH 1-bbl used in Tripower 200 Falcon sixes and Volkswagens and Land Rovers uses the same emulsion tubes.

viewtopic.php?f=1&t=70111&p=538319&hilit=Weber+ICH+34#p538319

The 65 valid choices in the Weber chart are then referenced with another number like this

xctasy":23uw9uf4 said:

When you run a big cam, you might need to change emulsion tubes.

Now three questions.

First, Powerband, what were the stamped Well Tube marks on the ex Cologne V6 5200 you had?

Second. stanyonHave you sorted and verified your 278 Clay Smith cam card yet.

Third. stanyon. You are using the 32 36 DFAV aren't you?


Elsewhere, I've been doing some research, and the 5200 Holley Weber kit has some differences the 32 36 DFAV. Holley calls it a well tube, and it has 14R XXXX re order part number, but is physically stamped with numbers like 04, 05, 74, 75 common.


That is if the well tube is stamped 04 its part number is = 14R 1004
05= 14R 1005
74=14R 974
75=14R 975


Weber has a whole brace of 65 call names skipping through F1 to F87 for the similar 61440.xxx series emulsion tubes http://www.webercarburatori.com/?p=handbook&s=2. There are 13 heights from 30.5 to 53 mm, and about 5 hole and tube width combinations which make up the 65 tubes. Some aren't compatible with the different float types, even though they fit the well/emulsion tube


This is from what Holley and Colt Industries developed the 14R xxxx series from.


The Holley Well tubes and Weber Emulsion tubes can be swapped, and allow the engine to run in a more healthy, higher performance setting. Turbo 974 and 974 well tubes can be used for draw through 5200 and 32/36's, as this is what Ford designed them to do in the 2.3 Carb Turbo Mustangs.

Below is not related specifically to the part numbers of common 32/36 and 5200 series tubes, but it shows graphically what a savage difference in emulsion tube/well tube hole size and pattern does.Air fuel ratio is changed every-time a different emulsion/well tube hole pattern is used.



There are other fuel jet call number differences between Weber and Holley Webers, but once you understand them, the jets and Emulsion tubes can be swapped around if they match.
If you wanna do it from first principals, then listen to this

https://www.youtube.com/watch?v=1pkFSA_ ... e=youtu.be


And then look at this 61450 series IR Port on Port Weber Emulsion Tube sketch, which isn't for our 61440.xxx series DF, DG, and 5200/5210/5220/6500/6520 series staged and synchro dual throats.

It shows what David Vizard was on about.




and read this. http://www.turbosport.co.uk/showthread.php?t=169101


On the Jeep forum, they have gotten into the Weber 61440.xxx emulsion tubes, and made some custom F-THIS ones very easily from some F7's to suit the 4.0 and 258 Jeep sixes with the 32/36 AND 38 series carbs.:mrgreen:

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

Click to expand...

http://www.jeepforum.com/forum/f8/weber ... ndex6.html

The only other thing that makes the 32/36 and its 5200 difficult is the little changes AMC/ GM/ Mopar and Ford requested each year from 1969 to 1983 (when these carbs were no longer used in the Big Fours Domestic Pacers, Chevettes, K cars and Pinto's/Rangers and Fox bodies). Each year they did a whole heap of fiddles, and as powerband has found, sometimes with all the bits swapped over, no two behave alike. Usually float setting, air bleeds or axillary squirters are changed subtly, and then you have jets, well tubes and air correctors and curb idle throttle settings and secondary flat or rich spots. Once these little changes are filtered out, you can have a lot of fun.

Click to expand...

The float levels have to suit the emulsion tubes, there are three kinds of float, and different kinds of tubes, which are not always the same height. The ones you find stock are little F50's, which are better changed for F6's, F7's, or F66's, or modified to F This like some have custom made. There is no one right answer, you can make F50 and F6 work too, but its harder, and an E-tube change is the best first step.

The main problem is emulsions tubes. If you've got a good 100 rwhp plus engine, you should use F66's in primary and secondary, and jet the primary lean, secondary rich, and don't be afraid to open out the venturis up to as much as 29mm primary and 31 mm's secondary. The second is the float level. The third is the combinations of changes that have occurred with any 32/36 or 5200-6520 series Holley Weber. Some have primary and secondary squirters, some don't, some have primary idle systems only, some have return lines, some have little changes. Ultimately, if you've got your pressure below 3 psi and ideally at 2.5 psi, and the right emulsion tubes, floats and venturi sizes and accelerator pump settings, then then the rest is just following orthodox tuning that you find on the United States Jeep, Opel GT, Datsun A series and MGB GT forums. Most of that is what has been listed above by the previous posters.

The 1982-1993 Aussie X-flow Falcons in 93 octane 120 to 148 hp (later downgraded in 87 AKI fuel trim to 118 and 131 hp trim) ran 137, 210 and F66 emulsion tubes with its Fiat style ADM 34/34, and it had smaller throttles than the Weber 32/36 or Holley Weber 5200/5210/5220/6500/6510/6520.

EightTrack and Xctasy,

Thanks for the great info. I have my distributor out getting recurved at the moment. Before pulling the distributor, I opened up the fuel regulator adjustment screw about 3 turns. It really helped out with the flat spot. I don't have a fuel pressure gauge hooked up, but I think the shop that did the motor install had it set around 2 psi. .

I'm sure I will need to do some fine tuning once I get the distributor back in but it definitely improved just by increasing the psi. I haven't been able to drive at wide open throttle as I am still breaking in the motor. This info will be really helpful when I start making adjustments to the 32/36, and I'm sure I will have a ton of other questions.

Thanks again,

66stang84

do yourself a favor and set your self up a fuel pressure gauge. most pressure regulators have some provision for this.

I plan on installing one this week, looks like there is a second outlet on my fuel regulator that should work. Thanks