DGV Settings

[64beam]

Hi again,

Please bare with me, but I have another question regarding the DGV carburettor (settings this time). Is the factory setting OK for the float level on the Alpine or have other people reset theirs? What is the best way to set the float height (is there a good internet site regarding DGV setup)? Lastly, on the secondary butterfly, there is a small stop screw which adjusts the butterfly. Should the secondary butterfly be fully closed or slightly open?

Thank you, Robin.

 

[Nickodell]

Please bare with me

But Robin, I hardly know you. Just because we have the same last name .....

but I have another question regarding the DGV carburettor (settings this time). Is the factory setting OK for the float level on the Alpine or have other people reset theirs? What is the best way to set the float height (is there a good internet site regarding DGV setup)? Lastly, on the secondary butterfly, there is a small stop screw which adjusts the butterfly. Should the secondary butterfly be fully closed or slightly open?

Thank you, Robin.

I wouldn't meddle with the float level unless there is a problem (over-rich or over-lean) that you can't correct with idle mixture adjustment or idle jet changes. If you do have to adjust the float level, this might help:

http://www.minimania.com/web/Displa...isplayType/Technical Information/ArticleV.cfm

The secondary butterfly only comes into operation in the last 1/3 or so of throttle opening, so I can't see any benefit from keeping it open with the stop screw, but I'd like to hear from a Weber expert on that point. Here are some other useful sites for Weber adjustments:

http://www.mgexperience.net/article/3236dgev.html

http://www.saabnet.com/tsn/bb/sonett/?bID=7232

http://www.theautoist.com/weber_carb.htm

 

[64beam]

Hi,

Thanks Nick for the reply (you never know we may be distant relations). To add to my original questions, I noticed there are holes drilled into the sides of the casting. What are they for?

Thanks, Robin.

 

[Nickodell]

Do you mean the ones inside the venturi or on the outside of the casting?

 

[64beam]

Do you mean the ones inside the venturi or on the outside of the casting?

The holes inside the venturi that are uncovered when the butterfly starts to open (I think the primary has them too).

Thanks, Robin.

 

[Wombat]

Robin

Those holes are the progression holes. They are linked into the idle fuel circuit and as the butterfly moves past them, they provide additional fuel to the engine to smooth out the transition form the idle circuit to the main circuit.

As for the adjustment of the secondary, the manual for the XE/XF Falcon (Weber 34ADM) says to leave it alone unless you have the equipment to measure the leakage past the butterfly. Can't be sure if this applies to the the DGV, might be more emission control related.

Good Luck!

 

[64beam]

Hi Robert,

Thank you for the reply. I thought they may have been the progression holes, but was not sure. I still have to get a manual for the Weber DGV so I can read up on how they work.

Kind Regards, Robin.

 

[64beam]

Hi,

In my travels around the internet looking at the Weber DGV's, I have noticed a number of these carburettors that are without the choke plates. The choke plates are to help richen up the mixture when cold if I'm not mistaken, so are they actually required?

Thanks, Robin.

 

[Bill Blue]

Hi,

In my travels around the internet looking at the Weber DGV's, I have noticed a number of these carburettors that are without the choke plates. The choke plates are to help richen up the mixture when cold if I'm not mistaken, so are they actually required?

Thanks, Robin.

I suppose that depends on the temperatures when you drive and your ability to pump the accelerator. It's been while since driving a carbed car with choke, but I'd say at temperatures greater than 60 F you would not miss the choke plate very much if at all. Driving a car at zero degrees F and no choke will give you a leg cramp!

Bill

 

[64beam]

Alpine/Weber Basic settings

Hi,

I have installed the down draught manifold and Weber DGV carburettor to the Alpine, but I am trying to find the sweet spot with the idle that is not too high. I have checked for vacuum leaks using carby cleaner and everything looks OK. I have tried tinkering with the mixture and idle screws and the timing, but just can't find the right point. My car has the Luycas 43D4 distributor which I still have to get recurved to the Alpine. Can anyone give me some advice as to what I should try in regards to timing, screw settings, etc to get me closer to my goal.

Thank you, Robin.

 

[alpine_64]

Rob,

What speed is the car actually idling at? Is it a constant idle speed? Is it perhaps the throttle sticking a little, have you checked the linkage is not jambing or even the butterflys? Perhaps the pedal rod or even return spring? Just small things to check, but could all cause issues.

As for the Dizzy, what kind of advance is it running? You are running the holbay dizzy? is it mechanical or vacuum?

 

[64beam]

Rob,

What speed is the car actually idling at? Is it a constant idle speed? Is it perhaps the throttle sticking a little, have you checked the linkage is not jambing or even the butterflys? Perhaps the pedal rod or even return spring? Just small things to check, but could all cause issues.

As for the Dizzy, what kind of advance is it running? You are running the holbay dizzy? is it mechanical or vacuum?

Hi Michael,

It seemed to idle best at around the 1200 rpm mark and was idling quite consistently. I did try playing with the timing and I could lower the idle speed, but did not sound quite right. I am 99% sure that the linkage is not the problem, but I could disconnect it to confirm that. I am not sure what car the distributor was removed from, so I do not know what the advancecurve is like and it is a mechanical advance distributor. I believe the Holbay distributor was the 23D4. I will try again tomorrow, so I will see how I go.

Thanks, Robin.

 

[Nickodell]

Hi,

I have installed the down draught manifold and Weber DGV carburettor to the Alpine, but I am trying to find the sweet spot with the idle that is not too high. I have checked for vacuum leaks using carby cleaner and everything looks OK. I have tried tinkering with the mixture and idle screws and the timing, but just can't find the right point. My car has the Luycas 43D4 distributor which I still have to get recurved to the Alpine. Can anyone give me some advice as to what I should try in regards to timing, screw settings, etc to get me closer to my goal.

Thank you, Robin.

The general system is to set the idle speed screw so that it idles just fast enough to not stall, then adjust the idle mixture screw in and out until you get the best idle speed (have someone monitor the tach., or do it by ear) and smoothness. From this point I would set the idle speed dissy advance
using a vacuum gauge. This won't have any effect on the advance curve, of course, but it is a starting point.

Many forum members replacing the stock carbs with the DGV have found the idle mixture to be way too lean for both smooth idling and, more important, not bogging down when moving off from rest. IIRC the OEM idle jet as supplied is .055mm. I had to bore mine out to .070 until it was right.

 

[64beam]

Thank you Nick for the reply. What idle speed do most people set their 1725 engine to? The DGV's have a secondary idle jet and is slightly smaller (.50 mm) than the primary (.55mm); When does the secondary come into play and do you need to upgrade the secondary jet with the primary jet? I have not taken the car out for a drive yet to see how the progression is, but I may need to open up/replace the primary idle jet too.

Regards, Robin.

 

[Nickodell]

I didn't touch the secondary idle jet because I cured my off-idle stumble by just boring out the primary. You can of course buy a seried of idle jets and just experiment by moving progressively up - .06, .065, .07 et seq., but I didn't for two reasons: 1) I like hand-fitting, and 2) I'm stingy.

I use a set of "wire size" drills in my model railway (i.e. all British locos and rolling stock, hence not railroad) hobby, and used these to progressively widen the OEM jet. You can get these from a good model shop. You'll also need the little hand-operated spiral drill to mount them in.

By the way, don't get fooled into thinking the accelerator pump is at fault. Many people start by taking this apart and fooling with it, often losing the check ball in the process.

 

[64beam]

After purchasing the DGV, I thoroughly cleaned the jets and passages to the best of my ability and installed new gaskets. I agree that I don't think the accelerator pump is the problem as I found out when readjusting the timing to around 8 degrees which made alot of difference. Still a slight stumble, but better. I have also found a place to buy idle jets at very reasonable prices (AUS$4 each Nick and not enough to break the bank even for the stingiest ).

Regards, Robin.

 

[64beam]

32/36 DGV secondary idle jet information

Hi,

I am currently waiting for my Weber DGV manual to arrive, but in the meantime could I ask someone that may have a Weber manual to do a bit of research for me. I would like to know when the secondary idle jet come into play and whether the primary and secondary idle jets can be the same size? It appears that I need to reduce the primary idle jet size as I am only 1/2 a turn out from fully closed on my mixture screw.

Thanks, Robin.

 

[husky drvr]

Hi,

I am currently waiting for my Weber DGV manual to arrive, but in the meantime could I ask someone that may have a Weber manual to do a bit of research for me. I would like to know when the secondary idle jet come into play and whether the primary and secondary idle jets can be the same size? It appears that I need to reduce the primary idle jet size as I am only 1/2 a turn out from fully closed on my mixture screw.

Thanks, Robin.

Robin,

I would like to know when the secondary idle jet come into play

The secondary idle jet ( actually a misnomer ) should not have anything to do with the idle setting of the engine. It only comes into play when the secondary throttle valve just starts to open. It supplies fuel through the secondary transition holes thereby supplying the engine's need for additional fuel due to the opening secondary throttle valve. This "idle" fuel is supplied until the secondary t-valve is open enough to allow sufficient airflow to start pulling fuel through the secondary main system. The secondary t-valve should be as close to closed as possible with no tendency to stick in the bore so as to not pull fuel prematurely through the transition holes. It would be next to impossible to set a reliable consistent idle on the primary system if your carb is pulling air and fuel through the secondary side at idle speeds, not to mention that it would destroy any chance of economical operation.

whether the primary and secondary idle jets can be the same size?

Could be but do not have to be the same size. I believe that Weber suggests using a .50 idle jet for baseline tuning assessment. The large majority of O/E idle jets in the listing I have are between .40 and .60 with a small sprinkling of larger jets for the secondary side.


HTH,

 

[64beam]

Hi Don,

Thanks for you very incisive reply. Basically the secondary idle is there for a nice smooth progression to full throttle. Now to get a smaller primary idle jet to test out my theory.

Thanks again, Robin.

 

[husky drvr]

Robin,

Don't know if you have found these instructions or not but they might be of some help.


http://www.redlineweber.com/html/Tech/carburetor_set_up_and_lean_best_.htm


http://www.redlineweber.com/html/Tech/32-36_dgev_parts_breakdown.htm