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MG MGA - another weber carburator question

I have completed installation of a 32/36 weber carburator on my 1959 MGA. I have been driving the vehicle without having the vacuum advance inserted into the carburator since I can't find where it inserts. Someone told me that it is not necessary for it to be connected. Is this true? WHere does it insert on the carburator ? thanks for the help

michael dvorkin
michael dvorkin

Michael. I am not a fan of the Weber DGV series, owning three MGBs on which it is installed. Given a choice, I much prefer the twin SU carbs which, in my opinion, is a much better system. (This for those considering such a change.)

The Weber DGV series has a small metal tube, near the base of the carb, which supplies ported vacuum for the use with the vacuum contol.

When installed "correctly" the float chamber is towards the front, the idle adustment is towards the cylinder head and the tube to attach the brass port, in the base of the carb, is towards the cylinder head.

Most of us choose to install the Weber "backwards". This moves the float chamber to the rear and allows us to have easy access to the fuel line, idle adjustment screw, idle misture screw and have the port for the vacuum advance to the outside of the exhaust manifold.

I use this "backwards" system on three cars, all of which perform well and continue to meet the required emissions standards.

But, I would never, ever, use such a system when the twin SU carbs are allowed. The SU is such a better, and much more sophisticated system, that its replacement by the Weber DGV is not an option.

Sorry to be so blunt about this, but this is the truth as I know it. The SU carb is only inferior to the computer controlled fuel injection system. In good condition, and properly adjusted, the SU carbs are superior to any other carb system available.

These thoughts are the product of owning both systems, in similar cars and replacing the Weber with the twin SUs between emissions testing cycles, and a lot of research into the matter.

Hope I have answered your questions. Hope, even more, that I might cause you to sell your "mildly used" Weber system to someone less tuned in, on E-Bay, and will revert to a properly rebuilt, and set up, pair of SU carbs.

John Twist, at University Motors Ltd., and Joe Curto, at www.joecurto.com, can rebuild your old carbs. Either provides first rate work and will tell you if your old carbs are
"beyond rebuild" stage. If such is the case, they may be able to provide a set of functional rebuilt carbs. Burlen Fuel Systems provides new carbs to various specifications, perhaps having some that will work for you.

I can only speak from my own persective, which has been with various MGBs. The Weber DGV series is slightly easier to tune for emissions testing (but very delicate in this matter) than the twin SU carbs. But, there is a very significant performance loss in the use of the DGV as compared to the twin SU system.

Les
Les Bengtson

I agree with everything Les just said about the Weber. I've used a new DGV carb, and I sold it as soon as possible. My worn SUs gave better performance and once they were rebuilt, the difference was amazing! Joe Curto and John Twist (University Motors) both offer an exceptional rebuild service!

The vacuum line does need to be attached, or performance will feel "flat." As Les said, there are ports at the base of the carb - and they probably have a small black rubber cap over them to prevent leaks. The upper one is ported vacuum, while the lower is full manifold vacuum. you will probably find better performance using the ported vacuum. You may also find that you need to adapt your vacuum line to a short piece of rubber hose to fit onto the port.
Jeff Schlemmer

I agree with Les. If you have a choice Don't use DGVs.
I have owned Japaneses Specialists Auto Repair Center for 25 years and wrenched in Datsun dealerships before that.
We used to see many different carburetor conversion kits for the 73 240 Z and the 74 260 Z. My memory the kits were: 70-72 original 240Z dual carbs which were SU copies, triple Webber, triple Delorto, Holly 4 barrel, and dual Weber DGV.
The Weber DGV conversion was only better than the original Hitachi flat tops but was the cheapest.
When I was able to locate new 70-72 carbs the car always ran better and looked more original.
The triple side drafts were poorly matched to normal street driving. But the SU copies that were used on early 240Zs were the best conversion by far.
DGV carbs are for the Lazy and Gullible. DGVs also ice up very easily in cold weather.
PS
Early Datsun products were close copies of BMC/MG vehicles in the 60s. Even today you can find MGA engine parts labeled to fit Datsuns.
R J Brown

I have played around with the DGV and concur - waste of time on an MG - you are far better off with SUs. I expect that a large part of the attraction for owners of anything other than late model single carb MGBs, which don't have as many options, is the Weber name, which smacks of performance.

Your post about Datsuns made me recall the show where they were preparing identical 240Zs for a drag race - I forget the nale fo the show, but you probably know the one I mean. Winner gets to keep both cars.

These idiots, obviously American car guys at heart, chose to toss the stock Hitachis, and replace them with a Holley 390 on a convoluted manifold. Gormless! I was hoping that one team wouldn't have time to swap carbs, and would then go out and beat the other team using stock carbs......
Bill Spohn

I ran a webber DGV on a 1500 Spitfire engine to replace the single Stromber carb. It had, what i thought at the time, adequate performance until i borrowed a set of HS2 SU's and tried them out. These are carbs for the 1200 and 1300 CC Spitfires but they easily outperformed the webber in all aspects except time required to tune them ( you can tune a single webber in about 40 seconds if you are slow about it) So, my 2 cents worth, bag the webber and put the SU,s back on......
Mitch Smith

This thread was discussed between 21/05/2006 and 22/05/2006

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