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MGB Stupidity.

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One more video, in case you haven't seen it:

 
Riding makes perfect sense. I put no effort on that. Im crossing my fingers here.
 
Thats got to be it. How in the world do you ensure they are not touching the post. with the wires Disconnected i lose continuity. could i put a small piece of wire over the rod?
 
no matter how I put those wires on the rod, as soon as i put the nut on it electricity would connect the wires to the body. Unless the nut was insulated itself.
 
Okay, this seems to be confusing you.
Positive ground, so the negative battery terminal is "hot".
Connects to the starting solenoid.
Clip your test light alligator clip to the hot battery cable on the solenoid.
Then touch the wire to the distributor. Does it light?
Disconnect the wire to the distributor at the coil and re-check...does it light?
If it does, there is a ground in the distributor.
Prop the points open with a piece of cardboard to make sure they are open, and recheck.

Just so you know, I have a letter in my files from NASA, they tell me this is NOT rocket science!
Dave
 
Mickey, you nailed it. Went real careful and ensured the wires in the distributor were not riding. that solved the continuity from the spade to the body of the distributor. Test light does light when touched to the body of the distributor. Only lights from the wire going to the coil if the points are closed. if they open the test light goes out.
 
still no power going to the coil from the distributor when the key is on.
 
The later Bs are negative earth so positive goes to the starter.
 
With key on and points open there is power in the wire connecting coil and points.
 
maybe its the 35 degree temp but i swear i just smelled some burning gas
 
A smell was about all I got and it may have been the cold getting to my head. I still have no spark.
 
And, as much as I avoid the old adage, "Replace the coil". You don't want to just throw one in "because", but now with the testing, wire to distributor disconnected, power on, power at one side of the coil, it's open on the primary side.

However, having seen corrosion issues before....check power on the wire lug in, then the coil stud where that power in wire bolts down. If good both places, check the stud on the output side to the distributor, then the lug.
Seen corrosion have it fail on one of those spots.
If power in okay at stud, power is making it to one side of the primary. If nothing on the other stud, it's open winding, one of the things that can happen when you leave the key on.
Get the correct coil for points, check to see if your y/m/m has a ballast resistor, so you get the correct coil for use with or without ballast resistor.
Dave
 
My last coil failed my bench test. I replaced it for a coil used in cars up to a 74 because I was using those years points. Under my coil in the box are instructions saying do not install on systems with a resistor or resistance built in to the wiring harness. What they mean is a ballast resistor right? From what I can read is that my 78 MGB has a resistor. Is that causing my spark to be so week nothing ignites?
 
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Weak spark. The ballast (in cars I did more work on) is bypassed by the solenoid to provide full power to the coil for starting.
You car MAY have come with one...and it MAY have one still.
Or it MAY have been removed when you put in electronic ignitors.
I can tell you how to test it if you want.
 
Electrics are me weak spot in mechanics if you couldn't tell already. It looks as though my car should. i never took them out when i went back to a points ignition but it was around for some time before i got my hands in it. Please do explain ill try to comprehend. As an update i went out to work again on some grounding issues im about ready to just let go on, and i turn the key. It sputtered once or twice and not again not matter how long I held the key on.
 
You have to have a load on the wire. Coil works, but we are now fairly certain the coil is fried. Since you don't want to get a new coil until you know which one....use a light bulb.
Test light should do it.
Since the coil is bad, turn the ignition on, using a decent voltmeter, check battery voltage at solenoid, then check ground to hot lead of coil. Note the voltage.
Then using your third hand (alligator clip leads can help here), connect the test light to ground AND the same point the meter is connected to at the coil. Note that voltage.
On a 12V system, with the light load of a test light, should be..oh..guess 1-2 volts less than battery voltage.
If the same, the resistor has most likely been removed or bypassed.
You can use a bigger bulb to load it more...just do this for a short period of time, like just enough to read the meter.
I'm trying to make this simple.

Resistors only drop voltage when there is current flow. Since you have no current flow through the coil primary, the voltage will be the same at all points of the system.
Granted, we could be reading bad Lucar connectors, poor ignition switch.....but give me the readings and we'll have some idea.
Dave
 
*deleted*
 
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Volt at solenoid ..................13
Hot coil & ground ...............8
" " with test...6.5 or 7
There is no question volts drop just a little. Dave you made that very easy to understand and execute thank you for you clarity.
 
Well....that's interesting. To have 13V battery, 8V at the coil with no load.......it's almost like there is something connected to the load side of the resistor other than the coil.

On an MGB? Someone, somewhere, sometime....messing with the wiring?
Nah....never happens, right?
 
AND LIFT OFF! well spark enough to get the motor running. Gunna run around the neighborhood to see how close i am to the bid run. I cant thank you all enough for going step by step with me here, and having the patients to walk me through something i am very unformilier with. Just the day before i left my key on and burnt out my ignition i was really stressed about the possibility of the "unknown" failing on my drive. I asked over and over "what could fail" meaning what have i not touched as of yet that i could have gone through. Because i have read a few posts I know I am in good company when I say I even took this matter to prayer and asked for help to know. Not only did i burn the ignition but i received answers on this forum faster and more constantly then i have ever before. Once again, THANK YOU!
 
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