Bruce gets closer to the Vltimate Trvth...
Well yesterday evening I tried to find why my LBC continues to die.
1. Vibration:
It also seems to be related to
hitting pot holes and other bumps and holes in the road.
2. Engine motion:
I'm begining to beleive that it is also related to needing new front
motor nounts. They appear to have the problem that all "Bs" seem to have.
(No, only old and poorly maintained ones -- sf :-)
So I'm thinking that maybe the engine is rising off the mounts and
causing something to be stressed, and causing a connection to be broken.
I say this even though I have yet to find where this is occuring.
3. Extra wear on throttle cable:
The reason I say this is yesterday at lunch I broke
the accelerator cable. I suspected it was going to eventually break as
it was frayed(sp?) (broken/missing some strands etc...).
Have you verified the presence and function of the engine ground strap?
There should be a braided copper cable connecting the left engine mount
to the chassis. If it's not there, several things happen:
- the ground current goes through the throttle and choke cables,
causing them to burn/melt/wear out
- the engine cuts out intermittently, often with a big BANG
- sometimes the whole circuit shuts off, lights and blowers and all
- the alternator gets very unhappy when its supply current is interrupted
and subsequent problems occur that appear to have no connection with the
original fault
If the engine mounts are as bad as they sound, you might well have a
flaky ground connection (if the previous owner even figured out why they
had a stupid wire holding the motor into the chassis). Try removing the
cable (if it's there), cleaning it thoroughly, cleaning the places where
it mounts, and reinstalling it snugly.
I'd also suggest that you look to the point where the hot lead comes from
the battery to the starter. This is a favorite crud trap, and the amount
of grease and road grime that can collect on the starter terminals can
cause intermittent opens. Also the heat and oil can gradually corrode
a lot of the insulation, leading to intermittent shorts. As a final
check, make sure your solenoid is firmly mounted to the starter (assuming
you have that kind of starter); it should take two, um, 8-32 x 1" fine
machine screws, I think, or whatever an 11/32" fine nut fits on. If the
screws are missing (and they do occasionally fall out), you'll not only
get intermittent weird starter noises, but I'm convinced that vibration
can cause the solenoid to move to such an orientation that it shorts
itself out and causes the car to stop running.
There's a whole passle of connections that are powered off the starter
solenoid; right now I can't recall where everything goes, but it seems
that the + terminal of the solenoid is used as the source for the
alternator, the distributor, the fuse block, etc. If you don't get
power to the + terminal of the solenoid -- at least on mid-year Bs --
you don't get power anywhere. (On the other hand, the Mystic 8-Ball
that lives between my ears is telling me "Reply hazy, try again later"
in round stentorian tones. Do please look it up. If I *really* loved
you, of course, I'd rush out to the boot of the '71 and look in the Haynes
manual I keep there for emergencies, but we hardly know each other... :-)
I'm almost to the point that my time is worth more than trying to fix
this and so I just might get a complete new wiring harness and install
it. [...]
And if you balance and lighten your engine it won't shake so much and make
things work loose in the first place; didn't know you could catch
shipbuilder's disease that far inland, did you? :-)
With that said what harness do y'all think I should be getting? The car
is technically a '77 MGB. BUT... it has a '65 engine and
distributor(25D4), an altenator instead of a generator, [etc. deleted]
I know that Victoria British sells replacement modules, if you will,
for the wiring harness. That is, you don't have to buy the whole
harness for the car; you can buy the parts between major junction
connectors and replace just the bad segments. This also gives you the
modularity to replace wiring segments for the appropriate year for the
components they service. Definitely worth checking out; I imagine
that many of the reputable mail-order shops will do something similar.
>From the sounds of the job that the PO did on this car, I'd suggest
that your first purchase should be a fire extinguisher...
--Scott
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