Fitting Electronic Ignition To A MGB

Kit of Parts for Electronic IgnitionWhen you have plenty of time, adjusting the contact breaker points on your classic car can be almost "fun" and on a nice summer afternoon there is nothing better than a bit of tinkering. Unfortunately most of us dont have that much tinkering time and those precious summer afternoons should be spent driving and not maintaining. This is how I found myself in the position of ordering an electronic ignition system for my MGB. The distributor on my MGB also looked original and was starting to show its age and I am sure that the vacuum advance had stopped working. Faced with having to change the distributor anyway I thought I might as well go the whole hog and upgrade to electronic system, new leads and coil. The in the photo it shows what you can get for not too much money (approx £80 for the lot!).


Removing The Old Distributor


1. Remove the distributor by pulling the pug leads (make sure that the leads are numbered for the plug they come off) and then undoing the clamp plate so that the timing is not disturbed. This was fine, pulled the plug leads off and then find that there is no way to get a socket or a spanner into the bolts for the clamp plate as the side of the distributor is too large and too close. The only way I could removed the distributor was to undo the pinch bolt on the clamp and slide the distributor out but then it would not go past the oil cooler pipes so I had to take off the distributor cap keeping the shaft as still as possible so the timing does not slip and put it somewhere safe. The old distributor can be seen in the photo below.

Old Distributor
Old and New Distributor with matched timing

2. Set the timing of the new distributor to roughly the same setting from the old distributor, this will give you an approximate setting so the engine will start and run. As you can see in the photo above both old and new have been set to the same rough position with the rotor arm relative to the distributor body. This means that the new distributor should slide in and make contact with the drive from the camshaft.

3.Slide the new distributor in and make sure it connects to the drive and then tighten up the clamp plate.


New distributor in place

4. All you have to do now is to fit the new coil and wire it up. The coil on the MGB fits to the inner wing by a couple of bolts which once undone release the clamp for the coil. The next bit is very important for an electronic ignition system, you must make sure that 12V positive feed to the coil actually goes to the +ve terminal. On contact breaker systems if this is connected the wrong way round the coil and the distributor will still function just not as well, on electronic systems you could blow up the electronic module. Check this feed with a multi meter before making the connections. Once the new coil is installed and the connections made there is a simple plug to connect the wiring from the coil to the distributor.

5. Now it fit the leads to the distributor cap and fit this to the distributor followed by attaching the correct lead to the correct plug.

Completed electronic ignition fitted


6. Go for a start, see if the engine will fire and run. If it does not the the chances are the wiring will be wrong as these engines will do something even if the timing is miles out. If the engine fires and looks like it is running OK then wait for the engine to warm up before adjusting the timing either with a strobe light or using my favorite method of using a vacuum gauge. Follow this link for information on timing with a vacuum gauge.


What a difference, straight away the car felt like it had more power and pulled really well. There was always a tendency for it to "pink" if going up hills if in too high a gear but now if fly's up hill without any problems. It feels like the best tune up you have ever done but being electronic it should not change and need adjustment. Definitively a great product and improvement and a highly recommended modification.




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| Updated 27-Mar-2010 |