Well, it's almost certainly something you have done, although it could be
faulty new parts :o) Plug lead order incorrect should be obvious as a very
noticeable misfire because if it is running at all it will only be firing on
two cylinders. You really ought to have measured the timing before you
started, so you could be sure you put it back to the same advance
afterwards. Whenever you mess with the points you affect the timing, so
putting the distributor back in the same physical position rarely results in
the same amount of advance. North American 71 model year cars were the
first to get manifold advance instead of carb, and this has a significant
effect on idling speed - making it noticeably lower if the vacuum is not
connected or working correctly. If it does appear to be connect to the
manifold properly remove it and suck on the pipe. You shouldn't be able to
draw any air through, and it should move the points plate clock-wise as you
suck and back again when you release. It does need a good hard suck to move
it.
Other than that I'll paste here what I said to a TD owner with a misfire
when hot, just substitute coil +ve for SW and coil -ve for CB:
"Could be absolutely anything. Did the problem only start after the work
and
new items? If so it is quite possible that one of those is faulty, heat
related failure of the coil is certainly one possibility. Fuel starvation
is another, if the tank vent is clogged. I don't know what a TD has but
non-emissions MGBs have a vented fuel filler cap. If this is replaced with
a non-vented cap you get a similar effect.
"But I'd start by clipping a timing light (inductive pickup type) to the
coil
lead and each plug lead, and watch the flashes both when cold and the
problem *isn't* happening to get used to how it should look, and again as
the problem develops.
"If the flashes get irregular on any of the leads as the problem develops
then it is an ignition problem. If not then fuel although it could be
plugs.
"If the flashes get irregular on the plug leads but not on the coil lead
(flashes here at four times the rate of any plug lead of course) then
probably the distributor cap or rotor is breaking down.
"If the coil lead gets irregular as well then it is coil, points, condenser,
or any of their connections.
"Connect a voltmeter between the two coil LT terminals and ground and again
get used to what the result looks like when it is not misfiring, and compare
it to when it is.
"I'd expect a relatively stable 14v (once the dynamo has started charging,
12v if not) or so on the SW terminal i.e. the 12v feed from the ignition
switch. Again a relatively stable signal on the CB (distributor) side, but
this time only about half that of the SW side depending on the dwell of a
TDs points.
"If the SW side starts varying when the misfire starts then it is
connections
from the ignition switch. If the CB varies and the SW is as before then it
is points, condenser or coil. If it goes higher then it is the connection
to the points, or through them, to ground. If lower then they could be
closing up, condenser breaking down, or coil going open circuit."
PaulH.
----- Original Message -----
> I gave my "B" a tune up last night, replaced points (set
> them at 17) replaced rotor, condenser and rotor cap.
> Now I'm having a hard time keeping the "B" idling...
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