Misfire, then dead, mg b

[rich.]

my mgb had a similar problem, it was due to a failing whatsit in the loom... i will try & remember what it was... capacitor? something like that anyway

[Topaz]

Have you checked the engine earth lead?

Few years ago my son had his Mini fully stripped for a load of bodywork and although the panel replacement and respray were great, there were a number of mechanical issues including a strange electrical problem that came and went with a regular flat battery. We had no mechanical knowledge (still don't ) but a few Google searches suggested an earthing problem - quite right as the problem was no earthing strap. Sorted that and been fine ever since.

Other problems were no split pin in castle nut so wheel came loose and using an angle grinder on the adjustable suspension to make it fit but it wasn't adjustable then as the threads were stripped. He's just paid £110 at the Mini show Sunday for replacements

Mike

[Richard Moss]

my mgb had a similar problem, it was due to a failing whatsit in the loom... i will try & remember what it was... capacitor? something like that anyway

Ballast resistor?

[Ian]

my mgb had a similar problem, it was due to a failing whatsit in the loom... i will try & remember what it was... capacitor? something like that anyway

Are you sure it's the whatsit and not the thingybob

[mach1rob]

The Distributor Doctor

Best avoided as I suggested earlier, at least while they sort out their recent batch of poor quality arms that fail spectacularly when their (bonded) contact lets go and usually take out the cap with them! We used to buy from them for any students whose projects were cars that used these things but - when their customer service (really sh***y attitude ) started to go downhill in proportion with the parts quality - managed to source an assortment of old stock arms and caps for the current list of such jobs. These won't last forever but the art department tell us that they have the means of creating things the Bakelite way so we're hopeful that a batch can be made, with the brass riveted as per the original - perfectly satisfactory when the correct insulation medium is used since Bakelite, unlike lighter phenolics or plastics, is stable at conditions of far greater severity than these found in a distributor.
It had better work as I've located almost three stones of suitable material in old radio cabinets that can be ground back then supplemented with a little of an equivalent, sustainable shell from current crops and reformed with fresh resin, just don't tell the radio forum guys or a new identity and cosmetic surgery will be needed.

I got my last one from here, and had no issues, it may be worth looking into (got a free keyring too with a £3 rotor!)

http://www.simonbbc.com/

[rich.]

my mgb had a similar problem, it was due to a failing whatsit in the loom... i will try & remember what it was... capacitor? something like that anyway

Ballast resistor?

thats the thing.. i must write that down

[TerryG]

or find the one in your loom, bin it and fit a proper coil.

[rich.]

thats what we did with my old b..

[Brit-car -fan]

I'm going to take a slightly different turn on this - my first port of call would be fuel / carb issues. It sounds like the engine runs until it warms up. Old fuel, partially blocked fuel filter (fuel starvation), blocked / old air filters (running rich), engine oiling up - look for blue smoke.
Or more likely to be:
If there is oil finding its way down the valve guides this will cause carbon build-up on the backs of the inlet valves and in the combustion chamber - check tuning (below) the RED HOT CARBON can cause pre-ignition, also causes engine to 'run on' after ignition switched off.
Also:
Could be a tight exhaust valve seizing in the guide.
Also:
Possibly overheating due to bad tuning / timing. - Check that points gap and dwell angle are correct with engine running (vehicle multi-meter), Check strobe timing at tick over (about 900rpm) and the other rev stages from the manual, this will tell if the advance springs are ok or not.
A;so:
Another cause of miss-fire and one that often gets missed is to make sure the points connector is pointing away from the stator plate. If not It can touch / spark-to the stator plate shorting out the 12 volts randomly instead of being governed by the points, this ussually tends to cause missifire straight away, but could be just when things get hot and expand. Worth taking the dist' cap off and vissually checking which way the clip is facing. This particular one had me head-scratching for ages - even ended up changing the camshaft!
Also:
Finally - when did you last change the plugs??