Control Box Calibration

[Iris.Caretaker]

I have installed a new control box (VR and Cutout) in the Mini (65 Deluxe) and it is working well. But I have just finished harness replacement on my MGA 1600 and I simply cannot get the generator to deliver sufficient electricity to cause the electromagnets to throw the points open in the VR. The max voltage I get between F and E is 3.2V but that's a about 3,500 rpm. I have tested the generator and it is happily turning out as much as 18V (before i killed the engine to avoid damage).

Any ideas? (Apologies for the non-Mini question here ...)

[Oneball]

Why are you measuring voltage between E and F? Most tests in the link below. You also need an analogue meter a multimeter doesn’t work for some of the tests.

https://mk1-performance-conversions.co. ... s_test.pdf

[Iris.Caretaker]

I was following one of the manuals which said to test between E and F. But thanks for Lucas reference. I wondered about the digital meter ... .

[Oneball]

F is the field winding not sure what the voltage would be but it wouldn’t be 12v. The regulator controls the current in the field windings to control the voltage output of the dynamo by increasing/decreasing the magnetic field.

[Iris.Caretaker]

Sorry - I mis-typed or mis-remembered. It was D to E I was measuring. I will try all the tests in the Lucas book once my analog meter arrives.

Thanks again.

[Iris.Caretaker]

Looking through the Book of Lucas, I see there are several references to the rpm of the generator as opposed to the engine. Are there are rules of thumb on this conversion? I know it depends on the size of the pulley on the generator and the engine ... . I suppose it might also be possible to measure the rpm using a timing gun ... ?

[mk1]

Never try & use a Digital meter on old car electrics. They will always read wrong because of voltage & current fluctuations. Use an ole style Analogue meter with a needle.