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MG MGB Technical - Points change now it won't run!

Had a spare 30mins this evening and thought I'd change my points and condenser as the car was running a little lumpy. I've now lost the light 3hrs later and the car still won't run. Have changed back to the originals and regapped several times. It doesnt even sound like its firing at all. What the hell have I done!!!!
It is the first time I changed them on my 1971 MGB but have done it a number of times on my midget and on my BGT many years ago so thought I knew what I was doing. Any ideas??

The points when closed are switching to earth. Incorrect connection could leave you with a permanent earth connection, then the coil won't charge, result no spark. Check that the low tension wire and condenser are ONLY in electrical contact with points spring (not the post) and that the spring is insulated from the base plate.
Allan Reeling


The problem physically hasn't been solved but your explanation has solved it in my head ready for first light tomorrow!

I think your right I've allowed the condenser and LT coil wire touch the post. Thinking about it, although setting the points is the same on both MG's the midget 1500 and MGB connect to the point in a completely different manner.

Many Thanks Allan

Yes, it's not uncommon to connect the condenser and the wire from the coil on the wrong side of the insulator.
Dave O'Neill2

Paul there'll be a good illustration and written details in the Driver's Handbook have a look at those, it'll also tell you about lubricating the points and dissy if required


as modern made CB points and condensers (and rotor arm) can be very poorly made and soon go faulty you're best not to change them unless absolutely necessary, clean points where you can and condensers are very long lasting and don't often need changing

don't forget to also check your rotor arm, dissy cap and HT leads

if you put new points in it's best to recheck the gap after a few weeks or hundreds of miles

setting/checking routine is this order - tappets, points & plugs, timing and carb mixture

a reliable place for good quality points, condensers and rotor arms is the Distributor Doctor -

Nigel Atkins

Thanks all it is now running much sweeter. TBH the distributor, internals, rotor, cap, leads etc are all looking a bit tired. If I have any spare cash after my holiday in a few weeks might replace the lot. The full kits from Accuspark look like very good value though I have read a few tales of people having fault ones sent in the first instance.

up to you of course but I know a B owner that bought one of their full kits and although he hasn't fitted it yet he did fit the HT leads and found they came apart (well there was a lot of components in the kit for a low price so costs have to have been cut somewhere

I can recommend a very good HT lead set make by the actual manufacturer who specialist in cables (who also manufacture for other ignition companies who put their name on) - and they have been independently tested by Peter Burgess and to his surprise they actually (very) slightly increased power - they are very well made and have a robust covering, I expect them to give trouble-free service for a very long time indeed (no I not on commission)
Nigel Atkins

Allan Reeling

How much would you want. It would have to be in a few weeks when I get back from Spain.

This thread was discussed between 10/07/2013 and 17/07/2013

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