After all the pushing and shoving on the forum, I've decided to write the definitive guide to the Weber DGV series carburetor.
This first post will include a short description of the carburetor, it's construction, a sample jet settings guide and a series of references for review.
Introduction
The Weber DGV series carburettor is a dual barrel progressive downdraught carburettor.
The various types are differentiated by their choke method and are mentioned below:-
The DGV is a standard manual choke.
The DFV is a mirror image of the DGV, for mounting on engines where the intake manifold is on the right of the engine. By mirror image, I mean that the carburettor performs identically, but everything is on the opposite side to the DGV. Most commonly found on Fords.
The DGEV has an electrically actuated automatic choke.
The DFEV is a mirror image of the DGEV.
The DGAV has a water actuated automatic choke.
The DFAV is a mirror image of the DGAV.
Each throttle valve is mounted on a separate shaft and they are of differential or progressive choke type. The linkage between the two throttle valves ensures that the secondary throttle valve does not open until the primary throttle valve is 2/3 open.
DAF, DFAV and DGAV types are equipped with a semi-automatic choke control. The carburettor is normally fitted to the engine as a single unit with both barrels feeding a common inlet manifold, the most common arrangements being a single unit feeding an inline four cylinder engine and a single unit feeding a v-type four cylinder engine
The carburettor identification mark is found on the lower flange outer surface.
Construction
The main body and cover of the DGV series are of die-cast aluminium or zinc alloy (Mazak) construction. The mounting flange is machined flat for fitting and the cover incorporates a mounting flange for the air cleaner assembly.
The throttle valves are of brass and the throttle shafts are of steel.
All fuel and air jets are of brass construction and are screwed into the main body. The emulsion tubes are also of brass construction.
Internal channels within the main body and cover are mostly drilled and are sealed with lead plugs where neccesary.
Performance
Most of the performance critera are improved byt he installation of a DGV Weber. Both mpg and horsepower are improved as the Weber has a very small input of fuel during idling and can open right up to larger than the standard Tercel carburetor.
A simple carburettor modification is not the first thing to do. As an ancient textbook on IDF Webers told me, it should be the last thing to do. Make sure your ignition system, fuel pump, rings and pistons, bearings and valve train are in good working order before you put the Weber on your car, as the carburetor will make all these systems work that much harder and possibly cause one to fail. Expensively.
Basically, performance with the DGV comes down to your right foot. If you're a leadfoot, then you'll push more fuel than is absolutely neccesary through the Weber and end up fouling plugs and coating your exhaust with fuel. If you're nice and lightfooted, then the Weber will only deliver the amount of fuel required, no more, no less.
One good idea is to listen to the note/sound of the Weber as you drive. Once you get it installed, you'll find that planting the accelerator into the floor at low rpm in a high gear leads to it bogging down and hesitating. You also get a low groan from the Weber. Doing the same at high rpm gives you a full-throated roar and pushes you back into the seat as the Weber gives the engine all it can take. Learning what the various notes mean is a neat skill to have. That way you can listen to what the carb is doing and either change up or down a gear to get best use of the engine.
Jetting
The Weber on my Tercel was sourced from a 2L Cortina and hasn't been altered since.
In the following jet settings, 1: indicates the primary barrel and 2: indicates the secondary barrel.
Aux venturi:- 1: 3.50 2: 3.50
Main jet:- 1: 1.40 2: 1.40
Idle jet:- 1: 0.60 2: 0.50
Air idle jet/hole:- 1: 1.70 2: 0.70
Emulsion tube:- 1: F50 2: F50
Air corrector jet:- 1: 1.70 2: 1.60
Accelerator pump jet: 0.50
Accelerator pump jet back bleed:- 0.30
Needle valve:- 2.00
References
Manuals
I used several manuals when researching the Weber carburetors.
The most useful are as follows:-
Weber carburettors owners workshop manual, J.H. Haynes and A.K. Legg., ISBN: 1850100616, 1850100209 (U.S.)
The Haynes carburettor manual., White, Charles., ISBN: 1859602886
Automotive Carburettor Manual (Haynes Techbooks), Chris Rogers, ISBN: 1859602886
The first on that list is the most detailed. Part 2, Chapter 7 deals exclusively with the DGV series Webers and I recommend seeing if your local library has it.
Online
<a href='http://www.google.com' target='_blank'>Google</a> will find most of the common information out there regarding Weber carburettors.
<a href='http://www.triumphspitfire.com/jets.html' target='_blank'>Triumph Spitfire</a> has the OEM jet settings for a whole heap of Weber carburettors. It's useful if you've bought a kit.
<a href='http://www.redlineweber.com/html/Tech/T ... ntents.htm' target='_blank'>Redline Weber</a> also has a good series of pages about general Weber info.
<a href='http://www.racetep.com/weber.html' target='_blank'>RaceTep</a> also has good info, but most of the stuff on the Web seems to be repetitive.
<a href='http://www.geocities.com/eraktoye/weber.pdf' target='_blank'>Weber tuning guide</a> taken from the first manual listed above. This has been the most use to me in servicing and tuning these carburetors. At the end of the file is a list of the OEM jet settings for the Weber I've got. If yours isn't listed, let me know and I'll see what I can find out. This chapter doesn't deal with the DGEV series, but they're so similar to the DGAV it makes no difference. If you aren't allowed to download it, then I'll see about putting it in a couple of other places. Maybe even here at Tercel4WD if I can.
Nothing beats a good manual that you can have open whilst you're taking things apart.
This post is by no means complete.
I'll also post some pics of my Weber conversion, but it's not that difficult. If you can take the carburettor off, you can put a Weber on.
Hope all this helps, and gets pinned, so I don't have to type it all again
