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MG MGB Technical - Weber 32/26 DGV Airfilter installation

Hello,

Can any one, please give me some tips on installing a new airfilter housing on a Weber 32/26 DGV carb (MGB 1974). Also I would like to know what the use if the the white plastic bend pipe that came with teh filter housing? Any copies of part of the Weber manual would be welcome. As I not technical at all, I let the experts tune my car.

Best regards

Eric
E. van den Berg

E.v.d.Berg: The white plastic bend has no function for your car. Some people might be tempted to connect the Positive Crankcase Ventilation system to the air cleaner housing using this fitting, but it wont really function as such. You, or your experts, will have to make a PCV. I did this conversion many years ago on a 73B and after experimenting with various combinations of US type PCVs, I installed the Smiths "mushroom" PCV found on the older (64-68) MGB engines. The base of the valve was connnected to the brake booster connection found on the manifold. If this fitting is not there you will have to drill and tap the manifold. Next you will need to connect a hose from the front engine side cover to the top of the PCV.
As the air cleaner, it should be simply bolted on.
PS I wouldnt do that conversion again. I think a set of rebuilt SUs would be money better spent. FWIW.
Regards, Andy
Andrew Blackley

E.,
My 74 had the HIF carbs and I've had so many problems that last summer I borrowed a used Weber 32/36 from our local britcar garage: www.motorwayltd.com It has the square K&N filter. The chrome base is bolted or screwed to the top of the carb (if I remember right, there are screwholes specifically for the base plate of the air filter). There are large "c" clips that hold the top plate and filter down. The original setup had the pipe from the front rocker panel going into a "y" and then each hose from the "y" went into each HIF carb. The Weber had 2 holes punched through the base plate of the air filter, so I simply ran each hose into each hole and have pins through the hoses to hold them in place. I really don't think it works. And there is no provision to use the evaporative cannister.
Like Anthony, I agree that it's better to go back to SU carbs. When finances permit, I'm going to get a new pair of the 70-71 HS4 carbs that have the plumbing for the emissions hoses and evaporative cannister, but with the separate fuel bowls like earlier carbs. That will be a far better setup.
If you want to stick with the Weber, do what Anthony suggests. It sounds like a great idea.
Ken T
Ken Thompson

Eric. On both of my rubber bumper cars, I am running the 32/36 DGV series carbs. The air filters are, as has been noted, attached to the top of the carb with bolts and the top and bottom chromed pieces, with the filter in between are held together with chromed C clips. On both of my cars, the front tappet cover is connected to the air filter via a length of hose running from the plastic elbow on the air filter to the pipe on the front tappet cover. The system has worked quite well for many years for both my daughter and me. I also own a 68 with the "mushroom style valve", so understand the concept Andy is speaking of. I have not found it necessary. The factory, when they changed to a carb vacuum source for the negative air pressure to the crankcase, ran the two lines to the carbs which Ken speaks of. This was a line from the front tappet cover to a Y seperator, thence to each carb. The principle is the same when using the air filter elbow. Both work well. Les
Les Bengtson

E. Since the parts are at hand you may wish to proceed as Les suggests. I have not owned the car of which I based my comments on for 10 years or more, so my experience is not fresh, as his is. My recollection is that I did have mine setup for a while as Les recommends and that there was more oily residue in the air cleaner than I liked, however.
Andrew Blackley

Andrew, I would completely agree that there is some oily residue in the carb air cleaner and some in the carb venturi. Whether this is objectionable or not would be personal opinion. On my cars, I take the air cleaner off at least once a year and throughly clean it, including the base and top plates. Our driving conditions are somewhat dusty and, any claims to the contrary not withstanding, you have to clean the air filters every year as part of your emissions tuning. I show a notable change in emissions before cleaning and after cleaning. If the venturi look a little oily (most frequently they do not), a shot of carb cleaner takes care of that problem. The biggest problem I have had with the mushroom valve is when the diaphram begins to leak, it tends to draw more oil into the intake manifold, resulting in increased oil usage. You can, I am reliably informed, hear the valve "hissing" when it is leaking. Mine was discovered in this manner by a friend. Unfortunately, after missles and the radio work required in weapons controlling, my ears no longer support "diagnosis by ear". In any event, there are now two working methods of how the system may be set up and anyone interested can try them out and see what works best for them. It would almost be worth a tech article on how to set up the system using the "mushroom" valve, if you have time to write it, so it would be available to anyone interested. Les
Les Bengtson

This thread was discussed between 27/09/2002 and 29/09/2002

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