Ahh... let me take a stab at this. The Weber downdraft carb has many
variables, or should we say, possibilities, in the form of multiple jets,
each with potentially multiple different sizes available. Since it was
never standard equipment in MGs, there is no "standard" combination or
set-up that is known by all to work perfectly first time. Someone who has
gone through the process on an MG before, or a Weber expert that is not
necessarily an MG expert, might be able to "dial it in" easily, but many
people who have attempted the conversion are disappointed in finding
"flat spots", or stumbles, on acceleration, or poor mileage, or other
problems, due to sub-optimal jetting for the application.
The twin SU setup, on the other hand, is extremely well documented, and
if the carbs are in good shape, and the procedures followed thoroughly,
it is difficult *not* to get them operating satisfactorily.
Once properly tuned, either should stay that way for a good long time, if
not indefinitely (if you can resist the urge to tinker), which is why I
suggested that Enrique forgo investing in the tool, and have a specialist
tune his Weber (considering the low cost he quoted). If he had SUs
instead, I might have encouraged him to attempt it himself, since the
procedures are well covered in the manuals, with further details on many
LBC websites -- not to mention the advice available on this list.
As to which is "easier" to set up, well, the Weber requires parts
substitution (different jets), so you would need both the parts and some
working concept of how they affect performance. That would take it out of
my range of expertise. The SUs require following instructions, being
thorough, and trusting your "ear" -- I have managed to become moderately
adept at this.
Now, if your Weber is currently performing acceptably, no "set-up" is
required, so that would certainly be the "easier" of the two. But if I
handed you a new Weber in the box, well... you see what I mean.
Donald Markham had this to say:
>All,
>Excuse my ignorance on webers, Why are they so hard to tune and are the SU's
>harder or easier to get tuned right? I curretly have a weber on my 72 GT but
>have recently pruchased a commplete SU setup to switch back. Please explain
>which is the easiest to setup & why.]
>
>Thanks
>Don Markham
>
>
>> Take it to the pro. You only have to do it once, so it's not worth buying
>> the Colortune and struggling with set-up, IMHO...
>
>
>
--
Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the red one with the silver bootlid.
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