Hi All,
Just joined the list and wanted to jump in with both feet. FYI, my first
car was a 59 bugeye sprite and while in high school I had a vast collection
of midgets. As I'm still experiencing my first childhood (forget about the
second!) I've gotten back into the MG "business" with the purchase of a
'73GT basket case and a '73 roadster. I just got done installing a new
clutch in the roadster and while I was at it I replaced the main and rod
bearings and timing chain. I also installed an almost new DGV from the GT
(GT had blown an engine before I got it).
The car ran almost fine before I removed the HIFs (bad idle, etc)
but now I get some backfire through the weber carb and no power. I'm 99%
sure the
timing gears were lined up properly when I put the chain on. Here's some
more data:
Car idles fine
Backfires through carb regardless of if and where vacuum advance is
connected.
Timing is at about 7 degrees at idle w/ distributor disconnected
Backfires under power at larger throttle openings
Car will continue to run even when mixture screw is fully closed
At idle fuel drips from the small feed tube in the small venturi of the
primary throttle bore (not the accelerator tube)
Donor car ran fine with the weber (until the engine blew up)
Weber was cleaned out prior to installation but didn't need much clean up as
it was almost new when put on doner car and wasn't on long before the engine
went out.
I also copied the following off of some other web site:
"WEBER 32/36 DGV (all MGB's 1963-1980)
While a very reliable carb/manifold set up, a disadvantage with this
carburetor is the fact that the primary venturi accounts for two thirds of
the throttle open position (no CFM* figures are given for this position)
with the secondary venturi becoming active in the final one third of
throttle movement. This carburetor requires excessive initial ignition
timing advance to avoid stumble on take off (if the ignition timing was
retarded, we would have to open the primary throttle plate to obtain the
necessary idle; this would expose the progression bleed holes which in turn
would require that the idle mixture be leaned to compensate for this richer
mixture condition. The end result being very little progressive richening
upon further throttle opening, especially at snap throttle and so the
stumble). Carburetor can be modified to allow the primary & secondary
throttle plates to open simultaneously plus modifications to the progression
circuit and accelerator pump at a reasonable cost. Unfortunately, the
company that had provided this service no longer does so."
Any suggestions would be greatly appreciated!
Thanks,
Dennis Vaders
Elkin, NC
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