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MG MGA - ignition confused

I installed pertronix ignition as described by Pertronix, couldn't get car to start. Removed it and went back to new points and condenser - still won't start. Place test light between distributor side of coil and ground and it's on all the time (rotating dist will not turn it off). Is the problem point gap? Visually the points open when I rotate distributor. Just confused and frustrated - any help appreciated. 1962 MGA MkII (positive ground). Thanks
Randy Roessle

Randy,

I am not sure what you are doing.
A test light between the distributor side of the coil and ground will always light up on all cars. Do you mean that the light is between the coil and the distibutor, part of the normal circuit?

Mick
Mick Anderson

Sorry, I am not thinking clearly at the moment. The light setup that you have should go on and off. When the points are open the current passes to ground through the test light, when the points are closed the current passes to ground through the distributor and not through the light.
Your distibutor must have a path to ground at all times instead of the "make and break" circuit.
Two likely reasons, a shorted condensor or incorrect assembly at the points pivot.
Can you try the test light with the condensor lead disconnected?
At the pivot do you have the insulators fitted correctly? The bottom insulator has the smaller diameter facing up. The top insulator has the smaller diamater facing down. The coil power lead and the condenser lead fit directly on top of the spring and under the larger diameter of the top insulator.

Mick
Mick Anderson

My brain is not functioning at the moment.
If your test light stays on all the time you have an open circuit in the distributor, not a short circuit.
Likely culprit is the lead taking the power from inside of the distributor to the points pivot. This lead is fragile and moves during the centrifugal advance operation. A break can be inside the wire insulation and difficult to find.

Now I will have a coffee and try and wake up.

Mick
Mick Anderson

Mick's 3rd response is correct:>) an open circuit to,or in, the disty is the only possibility.

Another possibility in the disty could be the breaker point plate grounding wire. It too is fragile and can fail. Or just maybe the points are adjusted poorly and cannot close. Or the wire between the coil and the disty has failed. Not too much else that can cause your problem.

Chuck

C Schaefer

Randy. Chuck is correct, as is Mick's third post. The light, attached between a ground point and on the terminal of the coil going to the distributor, will come on when current is not flowing to the distributor. Use an ohm meter to check out the continuity of the wire going from the coil to the points (also check out the terminal on the coil and the connectors to make sure they are clean and making good contact) and the base plate (points plate) of the distributor to the side of the distributor to verify the integrity of the ground wire. You should read "zero" resistance on both of them.

Les
Les Bengtson

This thread was discussed between 23/05/2008 and 24/05/2008

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