Scott Powers wrote:
>
> I have had it! ... <snip> ... Help please my wifes patients ran out a month
>ago.
>
> Scott Powers, 74 MGB Roadster (Lawn Statue)
Scott:
One of the things I've found with doing large-system rebuilds,
especially in the electrical area, is that betimes you get a bad part
(new) and just don't realise it. My method for curing this, if the
problem doesn't go away with replacement pieces, is to then go back
through the system one item at a time and swap in new elements. This
cuts down the variables in your experiment and focuses your attention on
each part as it is replaced. When you get something that works, you're
sure you've isolated the problem.
Personally, I'm a huge fan of thoroughgoing diagnosis prior to replacing
anything ... and of trying to isolate the exact cause of a problem
before spending any money. (I'm not made of the stuff, myself).
I've found, with the Weber DGV setup, the car wants 17 btdc. Fairly easy
to fine-tune it with the vernier on the side of the 25D. That's assuming
you timed the car while running; B's really want static timing, IMHO.
I've done both, but the static seems always a bit more accurate.
Does your timing 'wobble' at idle? If so, you could have a worn drive
gear for the distributor, or it could be loose. Is it possible you
installed the distributor 180 deg out of phase? This would cause some
very erratic behaviour in the engine, although it would run (just). I'm
particularly led to believe this since it's your apposite plugs that
aren't getting spark (#1 & #3). Are you certain you have all the wires
on the correct plugs? I know this sounds basic, but it, too, would cause
the sort of problem you're experiencing. Check your firing order and
visually check that the distributor is hitting those plugs in the
correct order. Are your pickup lead and condenser lead properly isolated
from your points? The 25D has a small plastic spacer between the two
sets of connexions, and if you install it in the wrong order, the car
won't run properly. The correct order is: plastic spacer, points
connexion, plastic spacer, condenser and pickup connexions. Be certain
that, when you tighten the little nut on this connexion anchor, the
condenser lead doesn't rotate around and contact the shaft of the
distributor. Also, be certain that your distributor is seated properly.
It's easy to think it's seated when it is not; it makes two distinct
'clicks' as it seats. Because of the difficult accessibility of the
retaining bolts on the distributor clamp, I've found it useful to remove
the clamp, widen its opening just a tad, then install the clamp to the
block and THEN to install the distributor; this is not the procedure the
manuals suggest, but it works for me. Tighten the clamp securely once
the distributor is seated. Finally, the way the cap is put together on
the 25D model, it's possible to get the plug wires installed without
having their contacts correctly inserted into the cap, thus missing
spark on one or even two of the contacts. Particularly on non-Lucas caps
(the replacement variety sold through most parts stores), it's very easy
to have enough gap that the spark plugs won't fire. Check this.
That's the best I can do ... good luck, and keep us posted as to the
results! This thing will be licked yet!
Corey
75 MGB 'Rags'
RD#373750
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