More electrical gremlins

[F1loco]

So, replaced practically everything I could in the ignition and fuel department, but she's still running rough at times under initial load. Once going and moving, it's not usually an issue, until a dreaded stop light. I did notice if I push down on the number 1 plug wire, it levels out momentarily. Starting thinking maybe there is voltage issue, so off to the regulator.

 

It would appear that when I insert a piece of cardboard on the regulator, start it, rev it to 3000, I'm reading in the area of 15.8 -16.2 at the battery - which seems OK. That said when it starts to peak, I did notice "sparks" in the back of the generator, followed by an immediate back fire pop out of the exhaust and then momentary lull in the engine until I release the throttle?

 

I then go the cut out - volt meter is wired between terminals D and E. Start the car, and rev and rev, and rev, never seeing the cut out close? It does go to zero with the key off as the circuit is open, so the part about it not leaking back to the dynamo seems to be functioning. That said, it's remains closed and cannot get it open, so I am thinking not enough juice is getting the distributor possibly? I've cranked the adjusting screw in the back two revolutions clockwise, but still can't seem to get it close. This was allegedly new pre-bench adjusted regulator from MOSS.

 

If I turn the key off and "manually" push down on it to open it, it does give off a nice spark.

 

Am I missing something? I did convert to negative earth, but other than the ammeter and dynamo, I didn't think I had to mess with the wires on the voltage regulator?

 

 

UPDATE:

 

So, I did the thing that didn't make sense. Went back to the regulator, and rechecked it. It was now low? Adjusted it back to 15.8 once it stables at 3K. At idle and w/o cardboard she sits at 13.5-14 at the battery, and revving maybe 15.3. Oddly enough the cut out started working and back to it closing around 13. That said my Ammeter which was set just above 0 before is steadily pounding around +10. Does this sound right?

 

Instead of "messing" around with it all, if I converted to an alternator, I could then remove the regulator, correct, as most alternator's have the regulators built in?

 

UPDATE#2:

 

So oddly enough my number 1 and 2 plug wires are reading about 380ohms, but number 3 and 4 are basically zero? Noticed the insulators were pretty hot when I pulled them as well.

Edited July 12, 2017 by F1loco

[Lebro]

Max voltage from the regulator is 15V, 14.8 is more friendly to the battery, & dynamo (probably why you saw sparks - too much output.

If you manualy close the cut in contacts they will remain closed till you pull them open again (engine not running)

If you are seeing 16V at the battery then the cut in contacts must have closed.

Check the resistance of your plug leads, they could be to blame for the misfire.

Suggest either convert to alternator, or get your regulator setup properly.

 

Bob.

[RobH]

If the ammeter is now showing a continuous 10A charge then something is wrong, probably the regulator is set too high now. It is difficult to be sure from your description what procedure you followed for checking and adjusting the regulator but this document describes the correct method to follow:

 

http://mgaguru.com/mgtech/books/pdf/Lucas_Generator_and_Control_Box_Tests.pdf

 

You probably need to make the voltage measurements with a moving-coil meter as a digital one may respond to odd fluctuations and not give a steady reading.

 

As Bob says, it would be worth checking out the plug-leads too as it does sound as though there is something odd there.

[F1loco]

Many thanks. Broke down today and ordered the alternator conversion kit to at least be sure the charging/regulating system is up to par. For $250.00 and a couple of hours of my time, seemed worth it in the end. Hopefully that will solve the pre-ignition stage.

 

The leads appear to be in correct order, 1-3-4-2. For some reason the smaller ones registered on the auto ohm setting, but I had to manually adjust for the longer ones. They appear to be spot on with Pertronix' 500ohm per foot reading. I did notice some "charred" tiny bits of fiber in the top of the plug inserts on the cap though that easily "shook out"? I looked at the cap pretty carefully, but didn't really find a crack. There is a hairline "scratch" under magnification leading from one of the contacts under the cap, but it appears not to go through all the way to the outside and only makes it about 1/3 of the way to next contact point. Not sure it is an actual scratch, casting mark in the plastic or enough to cause an issue. At least with the alternator, I should be good with the voltage being delivered to the ignition system and coil and work from there - I hope.

 

This forum is invaluable - especially since there is no one near me that works on these cars anymore.

 

Don