1977 MGB Bought On eBay

[june2020]

I recently bought a 1977 MGB on eBay and I had a question about the carburetor. I noticed while looking through the repair manuals that the MGB cars have two carburetors but my car has only one. Also the previous owner must have installed an aftermarket air filter. The carb on my car is a Zenith 175 CD-2 and like I said only one.
 
The car needs a lot of work done to it and I am capable of some. I replaced the spark plugs, the valve gasket and cover, spark plug wires and ignition coil. I took the carb apart and cleaned it out and put some new parts in it. My question is, is this unusual or is it okay? I had the car shipped to my home and when it got here I could barely get the thing started to get it off the trailer. I thought I just bought a piece of crap that didn't run. The ad claimed it was a daily driver but after looking at the engine I could tell that oil was leaking from the valve cover and their was oil on the spark plugs. I didn't pay a lot for it, only $3500. The car had the interior redone and the paint is in good condition. Oh and I also replaced the battery. It has sat for about a month trying to get all the parts either bought at an auto store or an online store.

I tried to start it and it doesn't want to start. It is getting gas and I made sure the spark plug wires are in the right place. I will leave it at this for now. Any suggestions would be great. The odometer shows 60990 miles.

Daryl Sessions

[amgba]

Get a Haynes manual, and either the Moss Motors, Victoria British or Thee Roadster Factory catalogs. The American MGB Association has 4 Technical Sections with real life situations and how to solve them. Experience with MGs is golden.

The old SU carburetors are great. They're simple and bullet proof. But you'd need a new manifold, too.
The ZS carburettor is not optimal, but in good condition, it should be fine. Make sure the internal diaphragm is not leaking.

Phillipe Tusler

[Art]

Hi Daryl,

I agree with Phillipe.  I'm not a fan of the Stromberg, but if is in good working order, use it to help figure out what else you might need in rebuilding the car. There may be other areas you'll need to spend money on.

If it is bad and you want to replace it with something else, there are different carburetor set-ups you can install to varying degrees of cost and levels of expertise.  Get the catalogs Phillipe mentioned and you'll see the options, but below is a quick reference:

- New HIF44 - This is a single SU carb that replaces the Stromberg using the same intake and exhaust manifolds.  It's basically a bolt-in replacement that requires the installation of a manual choke kit and some throttle linkage modifications only.  Runs about $600 for the kit.  Good as any SU and minimal work to install, but still a single carb.

- Weber Downdraft - Just as it says.  Similar carb to those used in 70's and 80's European cars from the factory.  Comes as a kit with intake manifold, air cleaner and linkage parts.  Can be ordered as an automatic choke (water or electric heated) or manual choke, which you then will need to install a choke-pull kit to operate.   Also needs an exhaust manifold, as the original intake and exhaust manifolds as a single, inseparable unit.  Note the 77 has a catalytic converter tucked-up under the exhaust manifold, so depending on where you live, you may have to reinstall one or, if like NJ that doesn't require inspections for cars over 25 year old, you can use a header kit or older (pre-1975) exhaust manifold and engine pipe to eliminate.

- New HS6 set - These are new, larger carbs as used on some Triumph TR6 and other makes/models.  Kit comes with a new adapter manifold and linkages for the MGB.  Larger diameter bore and manifold runners gets more air flow into the engine.  Not cheap (about $1900 with heat shield et al), but its not much more than other options when you consider they're new (not needing to be rebuilt) and add performance.  Same deal as the Weber on the exhaust.

- OEM New or Used SU HS4 - These are the older style side-float SU carbs which can still be found both new or used.  A new HS4 kit is much less than the HS6 set-up ($1000 or near half the cost).  In both instances (new and used), the same is needed for the exhaust system as the Weber and the intakes may be equipped with different ports and attachments for old pollution controls (i.e.: PCV valve center of the intake manifold) that you may have to eliminate and plug or figure out how to install.  Also note that the flange thickness of the manifolds varies with later models, so make sure you know the year you are working with the match the exhaust manifold or header to as you find them or order new from a catalog. You also need a heat shield, so if buying used, make sure to get that or buy one from the catalogs.

- Used HIF4 - These are the later internal float SU carburetors used from about 1970-74.  At the moment, these seem to be only available used or rebuilt, though all the rebuild parts are available.* Manifolds are similar but not exactly the same as for the HS4 (see notes on pollution controls and flange thicknesses), but either carb will bolt to either intake manifold and function correctly.  I like the HIF4 because it has an internal thermal adjuster that, when it set properly and works, automatically lowers and then raises the jet to adjust the mixture as it warms.  Same manifold situation as the Weber and HS4 sets.

*On all the dual-carb set-ups, also be aware that clearance for the rear carburetor is restricted by the power brake booster.  You should use a pair of thinner 'pancake' type air cleaners (like the Stelling & Hellings type) because the stock or K&N types will not fit there. With all used carburetors, expect to have to rebuild them, so figure that cost and time into deciding which route to follow.

Hope that helps you.  Good luck with the B and keep us posted.

Safety Fast!

Art