Chicagoland MG Club:Photos
Carburetor Swap Tech Day
May 8, 2004 - Wilmette, Illinois
Changing Single Z-S Carb to Twin SU's on Late Model MGB

This is what you get when you convert a rubber bumper MGB to dual carburetors.

Click for larger images. - Larger pics average 49KB.

This setup was purchased as a kit, with intake and exhaust manifold, and rebuilt dual SU HS4 carburetors mounted on the manifold. The kit was so complete that it had all the carb gaskets sealed in place and the manual choke cable attached. Steve Boswick made this one real easy for us, as he had most of the grunt work done before we got there. The water port on the back of the cylinder head was plugged, and the heater return was routed over the top of the valve cover. The Zenith-Stromberg carburetor and manifolds and catylitic converter and old exhaust system had all been removed. The new early type exhaust manifold was in place with the header pipe and the new Monza performance exhaust system was already hung. So the first order of the day was to part the carburetors and heat shield from the intake manifold and get the intake manifold mounted.

One gasket was torn during disassembly, so a little "blue stuff" came in handy. Everything bolted up slick as could be, except for the air cleaners. The K&N chrome filters would have to be exchanged later for tapered K&N's or round foam filters with domed covers. But for instalation, tuning and testing, we don't need the air filters. A vacuum tap fitting on the manifold was replaced with a (shortened) 5/16" fine threaded bolt and copper washer. The new early model distributor was a match to take vacuum from the venture of the rear carburetor.

Steve thought he would take it around the block for a little test drive, but we had time to order lunch before he returned with a HUGE grin on his face. Cowboy thought it looked too good to be true and had to try it for himself. End result is another HUGE grin. So Cowboy thinks he will now take the fast road cam out of his own street MGB and revert to a stock or fast street cam. By day's end we had a chance to check out a new CO emissions tester, which worked out nicely, and ultimately became the newest acquisition for the club tool crib.

For a more extensive look at some of tougher problems you might encounter during a dual carb conversion, also check the photos and notes from the March 2001 dual carb conversion session.

©2004 Chicagoland MG Club, All rights reserved.