MGB Just bought a 1966 MGB

[AngliaGT]

So you'll be "Ghosting" me then?

 

[jjroth63]

Here is the update for 8/27/2023:

7/3, I bought the car

7/6, I returned the car for fake VIN and undisclosed problems

8/26. I bought the car, for a greatly reduced price, drove it 200 miles home on the expressway at speeds up to 75 MPH. I had zero problems with the drive, but I now have a car that needs a lot of attention.

I bought a 1966 MGB that has had some modifications done by amateurs. I will break my concerns into separate posts.

Please help me find the solutions, I am not a mechanic, but I have some skill and ability to think logically.

Thanks,
John
Chicago

 

[jjroth63]

The 1966 MGB has been converted to a negative ground, with an alternator.

My first issue of concern:

The turning signals do not work. The head lights, tail lights and running lights in front illuminate, the switch on the steering column has been replaced, none of the interior lights work.

I removed the interior light bulbs, they tested OK. I would like to replace all of the lights with LED.

Please help me trouble shoot the turning signals.

Thanks,

John
Chicago

 

[jjroth63]

The 1966 MGB has been converted to a negative ground, with an alternator.

My second priority is:

The horns do not work, the wires are marked but disconnected. When I test the wires at the horns, there is always 12v power, this must be wrong.

I tested the horns with a 12v battery and they work.

I pulled the steering wheel and there was an bad wire connection. The purple wire is too short inside of the steering column to make a proper connection to the horn switch. I will probably have to pull the purple wire back under the dash and splice in a new piece to give me the proper length.

What are my best option to fix the horns?

Thanks,

John
Chicago

 

[jjroth63]

The 1966 MGB has been converted to a negative ground, with an alternator.

Another priority are the electronic gauges:

Fuel gauge and odometer work.

Speedometer jumps around, hopefully a clean and lube will help.

The tachometer, oil pressure and water temperature gauges do not move.

Where should I start with the gauges?

Thanks,

John
Chicago

 

[DrEntropy]

The dual OP/temp gauge is mechanical, an ether bulb (expanding gas) for temp and a copper pipette from engine to gauge for oil pressure. Only has an electrical connection for an illuminating bulb. All dash lights are (or should be) on red/white stripe wires. Solid red to rheostat for power, out from that to instruments.

 

[DrEntropy]

That cluster of dangling wires should be for the tach. It needs a couple slight mods to work accurately with a negative ground setup, not difficult. The white wire is the ignition from the switch to the coil, the tach works on induction pulse from that. The yellow wire is an "extra" circuit for an overdrive apparently not in your car, with the switch mounted in the opening to the left of the fuel gauge when fitted.

 

[DrEntropy]

Some things that may help:

Wiring diagrams Scroll down to the '66~67 one.

 

[jjroth63]

That cluster of dangling wires should be for the tach. It needs a couple slight mods to work accurately with a negative ground setup, not difficult. The white wire is the ignition from the switch to the coil, the tach works on induction pulse from that. The yellow wire is an "extra" circuit for an overdrive apparently not in your car, with the switch mounted in the opening to the left of the fuel gauge when fitted.

There are a lot of loose wires in this car.

I need a little more help to make sure that I understand. I do not have overdrive, is the "plug" normal or is there something else that should be there?

are you saying the tach wire should be connected to the white wire?

Thanks

 

[jjroth63]

The dual OP/temp gauge is mechanical, an ether bulb (expanding gas) for temp and a copper pipette from engine to gauge for oil pressure. Only has an electrical connection for an illuminating bulb. All dash lights are (or should be) on red/white stripe wires. Solid red to rheostat for power, out from that to instruments.

Is the rheostat the "P" knob between the tach and speedo?

What is the mechanical connection for the temp and pressure?

 

[DrEntropy]

There are a lot of loose wires in this car.

I need a little more help to make sure that I understand. I do not have overdrive, is the "plug" normal or is there something else that should be there?

are you saying the tach wire should be connected to the white wire?

Have a look at the wiring diagram. The white wire should have a small loop around a plastic holder which is held to the back of the tach with a small metal "horseshoe" clip. For an induction pulse, not direct connection. That plug is something someone used to cover the hole for a switch if overdrive was installed. Otherwise the hole had a metal plug fitted.

Is the rheostat the "P" knob between the tach and speedo?

What is the mechanical connection for the temp and pressure?

Yep. "P" is for panel... the instrument lights.

The temp and OP lines are routed thru the firewall to the engine compartment, yours are likely cut or not connected. Too many jackleg "mechanics" have no idea what they're doing, or consider it too much trouble to do it correctly. Some photos coming in a bit.

 

[jjroth63]

Some things that may help:

Wiring diagrams Scroll down to the '66~67 one.


View attachment 91897

I found a purple/ black in the turning signal switch harness, but it runs into the "loom" and under the hood I would think. I cannot find the other end of the one in the steering column, or is it soldered into the column and the brush connects it to the car?

I found the white and yellow wires.
What is the block?
It looks like one of the flashers is disconnected.
What is the :mount" thing behind the stereo?

Thanks,

John

 

[DrEntropy]

The capillary tube (coiled with protective wire) and OP lines from under dash to engine:

The OP line is aftermarket braided, this is source point for OP gauge:

Water temp ether "bulb" directly into thermostat housing:

 

[CARSINC]

The 1966 MGB has been converted to a negative ground, with an alternator.

My first issue of concern:

The turning signals do not work. The head lights, tail lights and running lights in front illuminate, the switch on the steering column has been replaced, none of the interior lights work.

I removed the interior light bulbs, they tested OK. I would like to replace all of the lights with LED.

Please help me trouble shoot the turning signals.

Thanks,

John
Chicago

View attachment 91862View attachment 91863View attachment 91864View attachment 91865View attachment 91866View attachment 91867

Strip all the Lucas wiring out.
Buy a Painless wiring harness and install it.
Buy and install all electrical gauges from Speedhut.

 

[jjroth63]

Some things that may help:

Wiring diagrams Scroll down to the '66~67

Strip all the Lucas wiring out.
Buy a Painless wiring harness and install it.
Buy and install all electrical gauges from Speedhut.

where does the painless come from, Summit does not have one

 

[BobHaskell]

where does the painless come from, Summit does not have one

Or you can go with an original harness from British Wiring.

 

[CARSINC]

where does the painless come from, Summit does not have one

Painless Performance Products or, Rebel Wire.
Just order a generic or hotrod kit

 

[CARSINC]

Painless Performance Products or, Rebel Wire.
Just order a generic or hotrod kit

If you want a true British wiring harness, I've got a spare

 

[jjroth63]

If you want a true British wiring harness, I've got a spare

I do not know anything about these, what is the time commitment to install? probably less than running down the problems.

 

[CARSINC]

I do not know anything about these, what is the time commitment to install? probably less than running down the problems.

You're correct. Forget the wiring harness. Just chase down and fix each problem created by the Dark Lord, Baron Verladimer von Lucas