1977 MGB BALLAST REGULATOR WIRING

[Lavo]

Hi, I'm new to this forum and I'm a total novice and I need help. I've been having starting problems for a while with my MGB. First of all the starter motor packed in altogether so I replaced it with a new one. Once fitted, the car turned over and started for a couple of seconds before dying. This situation is still ongoing and here's what I've done so far, new points and condenser and new starter/ ignition relays. I was told that that the symptoms my car is displaying points to a failed ballast regulator. Today I attempted d to fit the new ceramic regulator I purchased. I connect d the starter motor ignition post to the + side of the coil, the white/ green wire from the coil to the +post on the regulator and the other post on the regulator was connected to the + side of th coil also. I totally disconnected the old ballast wire from the loom. There is still no change, the car won't start. I am getting fuel through the carbs and there is spark when the car turns over. I believe I have wired the regulator incorrectly. Can anybody please help with a layman explanation of the wiring. Thanks.

[Geordie MGmike]

Lavo said:

Hi, I'm new to this forum and I'm a total novice and I need help. I've been having starting problems for a while with my MGB. First of all the starter motor packed in altogether so I replaced it with a new one. Once fitted, the car turned over and started for a couple of seconds before dying. This situation is still ongoing and here's what I've done so far, new points and condenser and new starter/ ignition relays. I was told that that the symptoms my car is displaying points to a failed ballast regulator. Today I attempted d to fit the new ceramic regulator I purchased. I connect d the starter motor ignition post to the + side of the coil, the white/ green wire from the coil to the +post on the regulator and the other post on the regulator was connected to the + side of th coil also. I totally disconnected the old ballast wire from the loom. There is still no change, the car won't start. I am getting fuel through the carbs and there is spark when the car turns over. I believe I have wired the regulator incorrectly. Can anybody please help with a layman explanation of the wiring. Thanks.

Lavo, I'm a little confused by some of your terminology and if we can get a common understanding it might help make things a little clearer.

first up.. It's a Ballast Resistor not regulator.
What do you mean by "the starter motor ignition post"?
What colour was the wire you left disconnected?
Was there one or two white green wires in the terminal you moved over to the resistor?

However, I'll try to answer your question...
During cranking the starter relay by-passes the ballast resistor to get full 12v at the coil +ve. This allows the coil to produce a good spark even if the battery voltage drops slightly whilst cranking. Once the engine is running (with the key returned to the normal/run position) the starter relay switches off and the coil +ve is fed from the ignition switch through a ballast wire in the loom.

If you are fitting an external ballast resistor you will also need to provide a new ignition switched 12v supply to the +ve end of the resistor with the other end going to the coil +ve.

Having said all that... If you have fuel, a good spark and the engine turns over quickly enough, there would appear to be a problem elsewhere!

Edited by Geordie MGmike on Sunday 7th June 23:35

[Lavo]

Cheers mg Mike, sorry about the confusion re my terminology, my head was up my backside by the time I wrote that post. My mechanic friend came around this morning to look at it and it appears that the new points and condenser I fitted were kaput. New ones were Fitted and my engine now starts. Thanks for the reply.

[Geordie MGmike]

Lavo said:

My mechanic friend came around this morning to look at it and it appears that the new points and condenser I fitted were kaput. New ones were fitted and my engine now starts.

Good to hear and unfortunately it's not unusual for replacement parts to be faulty. I guess there's another lesson for you... only change stuff when they are obviously knackered and then only one at a time to confirm it's good before you move on.

For condenser and rotor arms only use ones from the Distributor Doctor http://www.distributordoctor.com/distributor_conde...