Greetings,
It's me again. I've got a longish plea for help with my '72 MGB.
I fixed the burned valve problem, while doing so I added an
Ignitor electronic ignition. I thought my points were bad, which
apparently they were to a degree, but I'm still not able to get the 'B to
run well. I retorqued the head nuts today and adjusted the valve
clearances. I adjusted the carbs' idle using a vacuum carb tool (the one
from Moss). By this time I could already tell it wasn't running much
better.
Next, I tried to adjust the timing with a strobe light, but if I
came anywhere near the 'correct' timing, according to my Haynes manual, it
would start missing. As I advanced it (the mark was no where near where
it should have been, probably between one to three inches further down),
it would fire regularly.
So, I take my Colortune plug and commence to adjust the mixture
(HIF SU's). The front one I got down to the blue flame easily. When I
was doing the same to the rear carb, as I enriched the mixture, it
started trying to die, despite the fact the Colortune indicated it was
still running lean. I had trouble getting it started again. I backed the
mixture out, started it, and tried the adjustment again, and seemed to get
something approaching blue, but not really blue, but I decided to try it.
Tried to go around the block, but it was cutting out horribly once
above idle. I monkied with the idle adjustment, the timing, and the
mixture some more (and cleaned the plugs, which seemed slightly fouled,
though not badly). It sounded like it was idling fine, so I was ready to
take it to the store (hungry after messing about with it). Anyway, it
started missing, not quite as bad, but very noticeably (it wasn't a
regular skip as one would expect with a burnt valve :). Being much
agitated at this point, I abused it severly, accelerating through its
protestations. When I came to a light, it didn't want to idle, and almost
died. I got on a small highway and cranked it up, it started to run
better. The next stop, it again didn't want to idle. Then I pushed the
RPM's really high for about a mile. When I came to another sign, the d*mn
thing idled just fine, and it seemed to run fairly well from then on, not
missing or thinking about stalling, but it doesn't seem to be running
terribly well either.
Something isn't right. The compression isn't great, but it's
good enough that it should run better than it is. The valves are all ok,
they were reground etc., just last week, some replaced. So, considering
the advanced timing required, I wonder if something is wrong with the
vacuum or inertial portions of the distributor? As far as I can tell, the
dizzy is the original, and the vacuum unit's shell is rusty as heck,
probably where the heater leaked on it in the past (the leak is no more).
I've never taken it out of the engine and looked at it, mainly because I'm
not really sure what kind of signs indicate that it needs refurbished.
The rotor shaft doesn't wobble perceivably when I try to move it with my
hand (presumably it wouldn't matter if it did, since I've got the Ignitor
in there...for those unfamiliar, it just replaces the points, magnetic
induction [I think] triggers it to fire, with no physical contact
necessary, so I think shaft wobble would have minimal effect, unless it
was very bad indeed). Could the vacuum be stuck or the inertial weights
be too tight or loose, thus causing poor timing and resultant poor
running? Could a bad coil or bad plug leads cause the described problems?
The leads, on visual inspection, look fine, but they are at least six
years old. I haven't tested the coil, but, obviously, it does spark and
so do the leads (or it wouldn't run at all Batman).
Please forgive the excessive length! This is getting very
frustrating. I'm open to suggestions, including advice to put her out of
her misery, which I _really_ am feeling like doing. Seriously, if any of
this suggests something to you I don't see, please share your insight!
Thanks much.
-Scott Allen
js-allen@students.uiuc.edu
"At dawn we will face the greatest test of our resolve. But I
say this: though starving, hunger will not weaken us; though diseased,
illness will not cripple us, and though weary, exhaustion will not claim
us. We can fight knowing that all true Reiklanders will forevermore
honour our valiant gesture of defiance, even though our bodies be left to
feed the beasts of carrion.
Mind you...we could always surrender." -Rick Priestly's Siege
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