I've owned a '77 MGB for about three years and have never been able to
get it running very well. My brother and I recently pulled the engine
and rebuilt the overdrive (which now works!) and took off the head and
cleaned up the valves and piston tops. We rebuilt the Zenith-Stromberg
carb (including replacing a worn needle) and fixed numerous small
problems that had existed for some time (oil leaks, pressure switch
that controls anti-runon valve, thermostat, coolant leaks, etc.)
We spent half a day playing with the carb settings and timing and the
only way we could get a reasonable level of power out of the engine
was to advance the timing 10 degrees past the factory recommended settings.
Otherwise the car had little acceleration and backfired a lot.
It was difficult to get the idle down to 900 rpm using the fast and
slow idle screws and we found that the air idle adjustment has little
or no effect on idle. Has anyone ever encountered anything like this
before?
We also raised a lot of other questions:
The carbon cannister is supposed to be replaced every 15,000 miles or so.
I've put 15,000 miles on the car and I'm sure the previous owner
never changed it (considering the condition the rest of the car was in)
so the cannister is probably well past needing replacement. What
affect would this have on the engine? Can it be bypassed or taken
out of the circuit to see if it's causing trouble? (We opened it and
it looked clean inside.)
We also tried the tests in the repair manual for the gulp valve and
egr valve and found them to be ok but leaning towards marginal. How
would this affect the engine?
In the electrics for the overdrive the schematic shows a vacuum
controlled microswitch whose purpose seems to be to switch the
overdrive out when the car drops below 30mph. (This is not to
be confused with the solenoid valve that connects the vacuum to the
distributor when the car is in fourth gear.) The switch is
missing in the car and the catalogs and repair manuals make no
mention of it (other than in the schematic.) Is this switch
really supposed to be there and if so what does it do and where
can I get one? (Note, the overdrive currently works without it.)
Finally, can any one give me an idea of what it would cost to
get the rocker panels (and the sills in front of and behind the
panels) rebuilt? By 'rebuilt' I mean new metal welded into place
and repainted. Some of the structural metal may need to be
replaced also (one jack point is weak.) Anyone know of a good
place to get this done in Western Massachusetts or perhaps an
individual that does MG work on the side? (I've tried doing
body work and I'm no good at it.)
Please respond if you have had similar experiences and know
of some solution. Thanks!
ron@vicorp.com or uunet!vicorp!ron
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