Max is right, there are some differences with the 66 and 71. On the 67
carbs, both float bowl tops have two fuel connections - an inlet and an
outlet. The description is much as Max has it. I have a picture of my 67
BGT showing the front carb and the line that leads to the rear carb -
http://www.imt.net/~dcouncil/mg/carbs.jpg. If you look close, you can see
the metal fuel line behind the valve cover where it connects to the braided
fuel line. Overflow lines are connected to two steel lines that run to
below the oil pan.
The main difference on the newer SUs (71) is that one float bowl has three
connectors instead of two. On the 71, at least on mine, the steel fuel line
continues to the firewall and then runs towards the radiator. A rubber line
connects it to the front carburetor float bowl. This front float bowl has
the three fuel connections - the inlet, an outlet that has a line that runs
to the inlet connection of the rear carb (the same fuel line you see that
joins the rear and front carbs on the earlier SUs), and the overflow
outlet. Both overflow outlets are also connected to each other with a steel
line, a T fitting from that line allows another line to run to the charcoal
cannister.
I sent a message earlier that I would take pictures. I was a bit hasty - I
forgot that my 67 BGT is outside under a pile of snow, evicted from the
garage while I convert a TR7 to SU HS6 carbs. My 71BGT is under a tarp,
also snow bound. So the picture above is all I have for now. I should get a
chance Saturday to provide a visual description to all of this.
David
At 07:02 PM 1/18/01 -0800, Max Heim wrote:
>I suspect the plumbing is a little different between a 66 and a 71. Smog
>stuff, you know...
>
>On the 66, it's pretty darn simple. The metal fuel line comes up the
>passenger side (NA) of the firewall and crosses behind the engine. There's a
>threaded fitting (frequently hacked off) to a braided, flex fuel line which
>curves forward and runs into a "tee" as it nears the rear carb. At the
>"tee", one branch continues forward to the inboard nipple on the front carb
>float bowl (this branch is held in place by two handy loop clamps); the
>other branch goes straight outward to the rear carb inboard nipple. In
>theory (since they're invariably missing), the outboard (air cleaner side)
>nipple of each carb is connected to a metal overflow pipe which runs down
>the side of the engine, until they converge in a bracket down below and
>behind the driver side motor mount, and extend just beyond the oil pan rim.
>
>Note that there is no fuel filter in this description. If the threaded
>fitting on the metal fuel line is missing, it is convenient (well,
>necessary) to use standard fuel hose instead of the metal braided OEM one
>from this junction to the "tee". That makes it easy to cut and insert an
>inline fuel filter in this stretch. Because of the tight curve I found that
>a right-angle filter worked better than a long, straight-through one, by
>eliminating the possibility of kinking. I picked one out at the parts store
>by just looking at the ones in blister packs. The one I found with the right
>size nipples fit a Toyota 2L-- I figured that should have plenty of flow
>capacity.
>
>Hope this helps.
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