MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - Distributor Low tension wires

I cant get my 1500 started. When I checked the spark on the points it seemed fine, when I checked it at the spark plug there seemed nothing. I replaced the coil (and points and condenser). When I put the coil in I accidentally put both wires on the same side of the coil and turned the engine on. This burnt out the very fine wire in the distributor from the points to the external plug that goes to the coil. I have replaced this with a bit of wire from an old condenser so that it has the correct connection for the point and soldered it to the plug.
I still can’t get her started, though I have a spark at the points and at the plugs. Not sure if my repair is causing problems and why the wire in the distributor is so fine. I can’t believe that such a short piece of wire would have any resistance???


Garreth
Garreth

Hi Garreth. I am certainly not an electrical or ignition system expert, but can tell you a few things and perhaps make a suggestion or two also. The fine wire in the distributor is so fine because it needs to move and flex as the vacuum advance moves the baseplate inside the distributor. Heavier wire would fatigue and break, which would eventually kill the ignition. I once replaced the fine wire you speak of, with a thicker piece of wire, (on an emergency basis) and the engine started and ran quite well until the proper braided wire replacement could be installed. Since you do have spark at the points and the plugs, that would indicate that your thicker wire replacement is working. You might want to check the point gap again, to make sure that it is correct. It sounds perhaps like the problem is not in the ignition system but elsewhere. I am wondering if you are getting fuel to the carbs? Perhaps squirt a tiny bit of gasoline or ether spray down each carb, and then try starting. If the engine starts, then dies, you likely have a fuel delivery problem. I dont know if this is possible, but I am wondering if the short circuit somehow damaged your fuel pump or fuel pump wiring? Additionally, you might want to pull your spark plugs and make sure they are not carbon or oil fouled. This can easily cause an engine not to start! Lastly you WILL need to replace your condensor wire with the proper flexible braided part as soon as possible. Your replacement will not last, and could impede proper operation of the vacuum advance system. If all else fails, try reinstalling the old distributor condensor. Sometimes new ones fail or are marginal. Cheers! Glenn
Glenn

Check the timing - best to do it statically with a bulb. Check the points gap. Set the engine at the right point below TDC and then connect a bulb between the distributor low tension terminal and ground. Rotate the distributor till the bulb comes on, then rotate slowly backwards until it JUST goes out. This means that the points have just opened, and the timing is done. Tighten the pinch bolt, the car should start.
dominic clancy

Garreth - Not trying to insult your intelligence, but do you have the correct wires going to the plugs? It's easy to get them on wrong and then the engine refuses to start or if it does, it doesn't run worth beans. Good luck - Dave
David DuBois

I purchased a new plastic terminal thing from Moss that takes the wire from the points to outside the distributor.

I found if you pushed it on/down too far it shorted out on the slide plate inside the distributor, thus stopping the car from starting...

The solution was to press it on partly and the fit the distributor cap, which gently pushed it down.
If you take the cap off again and press it down, I found it would go down about another 5 mm.

Yet another quality repro part.


I have been using the MGB one with the spade terminal rather that the MGB screw terminal one though.

Anyone else seen this problem ?

Not sure if this will help you thought Garreth.

Quick check is to take an INSULATED flat blade screw driver and short it across the points. If you get a spark you laughing if not work back from there.

Cheers <MARK>
Mark Hester

This thread was discussed between 19/06/2005 and 20/06/2005

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.