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MG MGB Technical - Best carburettor

What is the best conversion kit for replacing the Zenith Strombers on a 1980 MGB. I am thinking about the Weber at Brit-tech

cec
Cec Fry

Cec-
"Best" depends on what your priorities are. What do you want to accomplish? Stone-reliable Daily Driver? The downdraft Weber DGV is a good choice. Performance? Twin SU HIF4s on a Maniflow intake manifold.
Steve S.

On my MGB I am using a Weber DGV. It gives solid performance and reliability. I hear that for the best streetable performance the twin SU's are best. And of course, basically for the race track only theres always the sidedraft Weber's.
K McCaffrey

Cec. Depends on what you use the car for and what level of performance you want. I prefer the HS-4 carbs to the HIF-4 because the HIF series has some "automatic" features that the HS series does not have. However, either carb set makes a good addition to a later model, NA spec car. (The UK spec cars continued to use SUs.) There are some minor problems with the SU set up. You need to find air filters that will fit and not be in the way of the power brake booster (brake servo). Most people use a version of the K&N filters for this. The second problem is the vacuum fitting for the brake booster. This must be fitted to the SU intake manifold. Much information on this conversion in the archives.

The Weber DGV series is an easy conversion. It works quite well when there is an emissions testing requirement. The standard coversion is to the 32/36 DGV/DGAV/DGEV carb. I prefer the DGV which has a manual choke myself. The problem is that the opening of the bores is progressive, meaning that the main bore, of 32 mm, is the one that is used until you have applied about 3/4 of the accelerator pedal travel. At that point, the secondary bore of 36 mm opens rather quickly. An excellent emissions and economy carb, but it lacks the performance of the twin SUs having simultanious opening 38mm bores. Brit-Tek has a Weber 38/38 with simultanious opening throttle plates which should, unless you have emissions testing requirements, work exceptionally well as a performance carb.

With either modification, you need to use a different exhaust manifold/header system. Make sure the flanges of the intake manifold and exhaust manifold are the same thickness so they will seal properly when tightened down. With the SU intake and factory exhaust (pre-75), there were two thickness of flange. Make sure the ones you would purchase are the same thickness. With the Weber and headers, you will have to shim the thinner flange to the size of the thicker flange. Once again, this entire subject is covered in the archives. Les
Les Bengtson

Les has covered it all very nicely. I do agree with him about prefering the HS4s --I put them on my 76B and it runs like a charm.I have just helped a friend convert from a DCOE 45 side draught Webber-- which was an absolute bear--to twin HS4s and hes very happy.So this is what I would recommend as well.
Gil Price

I'd like to hear from anybody running the 38/38. Contrary to most board posts, I've found the Webber DGV 32/36 a reliable performer so far-4 months. Installed for a trial on the 77, the Web 32/36 has been real perky with the $34 simul-lingage. The 38/38 should be a "poor-mans" sidedraft.
vem myers

Hi,
I just need a realiable Carb that will start the car without too much hassel. My stromberg just wont start the engine when it is cold without shutting down I have to restart several times. It's Ok when the engine is heated up starts first time. I have installed manual choke and did all the checks recommended here. I have made up my mind to convert and was wondering about the best carb to use. Bri-tek has a complete Weber Conversion Kit for $499US. That seems to be a good deal? What about the HIF44 single ( I believe its HIF44) which replaces the Stromberg?

Cec
Cec Fry

Double check that the problem is in fact the carb. Strombergs have a general inclination to run on the rich side, so it's a little surprising that cold would be an issue.

Have you checked for vacuum leaks, good spark, and that all the linkage is moving as it should?

All that said, I find I have somewhat less trouble with my HIF4's on my 74 than with the HS4's on my 72.
Steve Aichele

CEC

I like what les has to say. I converted my 78 B a couple of years ago and used a local mechanic on my island to install it. I am really unhappy with installation, which I should have taken to a MGB shop someplace and it would have been done correctly. A pearl of wisdom here. At the same time they removed smog stuff etc. I had them put on a stainless steel header and they did have to shim it to match up. The DGV carb is really nice and after being set up correctly really adds pwr over the standard piece of crap.

ONe thing that I do have which mystifies me is I have a binding in throttle on full exceleration. Hanging open. I put a return spring on the linkage to help with this and did fix it but Im thinking I would really like to get the binding fixed. Does anyone have an idea here?

CW
CW Strong

CW: Sounds like the throttle cable is catching in its sheath. First try squirting some powdered graphite into the sheath, coating as much of the cable as you can expose. This may clear up your problem if the braided cable itself isn't damaged with a wayward strand catching. If that's the case, replacement is necessary.
Terry

Cec,

A friend has installed one of the new 1.75" single SU HIF kits offered by MOSS #370-678 to his stock 1978 B, and is quite pleased with it. It was a direct bolt to his existing manifold, and has a manual choke.

Regards,

L.C. '74 B/GT
Larry C.

Vem,

I installed the 38/38 from 32/36 this summer. I am very pleased with it. It has much more torque low down, and still gives 28-30 MPG at 80-90 MPH. It is a little miserable to get going when it is cool outside though.

Shareef
Shareef Hassan

Hi,
Thanks for all the help here. I have my Webber conversion on order from Brit-Tek

Cec
Cec

Shareef- Impressive to hear your endorsement as my recall is you are an MGB 1 3/4 man! Can you expand on the performance? On the 32/36 I noticed a "snappier" throttle over the HS4, but the HS4 seemed to have more "pull" once they got rolling. My hope was the 38/38, with about identical areas as the HS4 ( 38mm versus 39mm) and non-progressive lingage, would be snappy with strong pull ( sorta like Ahhhnold's in the Calif recall)
vem myers

I have replaced my Zenith with the Weber DGV conversion from Brit-Tech, and removed the catalytic converter, but my question is what should I order for the rest of the exhaust system. Pre-75 or what? Thanks,

Jerry
JERRY HOSIER

Just find an Austin Marina carb. It's an HIF-6 and they are already jetted right and are cheap. Get the whole manifold if a cat isn't needed and you'll have a much better exhaust system to boot.
David
David

This thread was discussed between 27/09/2003 and 02/10/2003

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