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MG MGB Technical - Not Firing up

My son and I are trying to get a 1972 mgb roadster started that was given to him for a gift.
The car has not been run in about 2 years, we put in a 26R autozone battery as car was converted to single 12 v battery. We have 12.79 volts at battery and 12.3 to 12.4 v at coil.
Fuel is pumping through to carbs.
I cleaned the rotor, points and inside of distributor cap.
Oil pressure is good 50 lbs.
Can anyone give me some thoughts as we have never had the joy of an MGB before and are lost in our thoughts.
Person who gave us the car also gave us the original MGB workshop manuel to help us out.
Thanks in advance.
B Barbour

Are you getting spark to the plugs? If not, check the point in the distributor and clean them. Cheers - Dave
David DuBois

Dave,
I'll check and let you know what happens.
Thanks alot,
Bruce and Shaun
B Barbour

First thing for a cranker but non-firer should always be to clip a timing light onto the coil lead and each plug lead and watch the flashes while you crank.

If no flashes on the coil lead then check the coil -ve is switching between 0v and 12v as you crank.

If stuck at 0v you need to check whether it is open circuit or permanently earthed - the former is a faulty coil, the latter is usually points with no gap or a faulty condenser, or if the points have been changed since it last ran the wires could be connected incorrectly

If stuck at 12v check the points are clean and closing and the continuity of wiring to them, and the braided wire from the points plate to the distributor body.

If switching but still no flash then the coil HT could be faulty, or possibly the condenser open-circuit or not connected.

If the coil lead flashes but none of the plug leads do the rotor or cap are breaking down, if only some of them then probably just the cap.

If all leads are flashing as they should point the light at the crank pulley when on 1 and 4 to check that the timing is a few degrees before TDC.

If all that is OK it's probably fuel. Is the choke control functioning? Pull the plugs and sniff them. They should have a strong fuel smell but not be wet. Wet is flooded, but you can usually smell the petrol from the exhaust by then, crank with the choke closed and the throttle wide open until it fires then let the throttle go and half pull the choke to keep it running.

If the plugs are dry with no fuel smell after cranking fuel isn't getting through, could be float valves gummed shut if you are sure it is getting as far as the end of the pipe that pushes onto the front carb (assuming HIFs). Unfortunately the only way to get at these on HIFs is to remove the carbs, then the bottom cover, and you will need a new O-ring.
P Hunt

Dave,

Got spark at the points not the plugs. Rotor was fouled so we are getting new rotor and cap.Will go from there.

Thanks,

Bruce and Shaun
******************************************************

Paul,

Thank you for all the information.

We will be pulling out the timing light and checking everthing you listed.

Fuel is coming through but smells like varnish.

Thanks,

Bruce and Shaun
B Barbour

Rotor was fouled? They usually show burning along the curved face, and that is perfectly normal as the spark jumps a gap from rotor to cap contact as well as at the plugs. It burns in an arc, and indeed the rotor is as wide as it is because the relationship between rotor and cap changes with vacuum advance.
P Hunt

This thread was discussed between 17/01/2010 and 18/01/2010

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