New coil fitted - simulated drive seems OK

Despite being a bit frustrated the other day, I have to take into account a couple of things. It was the hottest day of the year and actually the hottest day I can remember for quite sometime. Once I had given up trying to start from broken down and had been towed home, that was additonal time and a nice cooling airflow. So still hopeful of an electrical issue, and still pinning hopes on the coil.

New one arrived today and of course an easy job to fit. Amy started fine (as usual - never had a problem from cold, so that proves nothing).  Also previously I had left her ticking over on the driveway for 10 minutes with no trouble either, so I wanted to try to simulate a drive as best I could with some high revs, constant medium revs, tickover, the up again etc etc...

With no moving air except for the fan, the water temperature reached a nice high level (still acceptable) and I ran her this way for a fair time. Certainly enough to simulate a work and back trip. A bit more really.

No issue. So on the face of it, seems OK. But of course I am nervous about it. It could still be something else that doesnt "trip" except under actual driving conditions. (bumping about more, being thrown from side to side, a different issue caused by the different stresses and strains of road driving??) A new condenser should arrive in the next couple of days. I wont automatically fit that, I want to get out and about for a proper drive as stated. But I want to tee up someone to tow me if needed this time, just in case!

We'll see.

Not so easy and stumped

OK, I was confused why just tightening my spark plugs fixed the problem. We are having a really nice spell of weather at the moment, so driving to work was on the cards again today. Started her up, warmed up a touch and set off for work.

Broke down just down the road, same problem as the other day. Managed to limp back home with a couple of stops and a couple of fiddles and because I was early, figured I'd spend some time checking again. At one of the stops (i.e. whilst the engine was not firing at all), I did have a plug out again and the spark was VERY weak, almost non existent. So that is still indicating electrics.

I went through as many connections as I could, ones that I hadn't touched the other day. Tightening ones that could have been a bit loose. Also the coil was a bit loose on the alternator, so wondered if that rattling around a bit too much could be contributing or maybe even has damaged it in some way. Anyway, got her going again whilst at home. She sat on the driveway for 10 minutes or so just running - all fine.

Against better judgement, I set off for work again, as if nothing had happened!  Got most of the way there and same problem hit me at the top of the hill near the office, I coasted all the way down and into my work car park, coming to a halt at the nearest space.

As of typing this entry I am having to think what the issue could be. Condenser? Failing coil? These are my best guesses at the moment. In the meantime, I am potentially stuck at work, with the working day ahead of me. So at the moment I have to wonder how I am going to get home when the time comes!!

Update 1: As of now, increasingly thinking a component deterioration failure. No fiddling AT ALL, I just went down and tried to start her up - no problem. A few of the internet articles I have read seem to indicate that Condenser / Coil could have this symptom of running fine when cold but failing when hot. I am hopeful of getting home, maybe in stages. I'll not fiddle and just wait and see, as that will reinforce the theory. Frustrating, but not terminal!

Also notice what I was parked next to. Nissan GTR. Very nice. This is the car that my son would have me replace Amy for!

Update 2: As hoped she started immediately and I started the journey home. Broke down twice by the time I had got to the top of the hill near my office!

No amount of waiting or fiddling fixed the issue this time, so called for a tow. Thanks M&D!!

Got towed home safely, no drama. An extra pair of eyes seemed to suggest lack of fuel. I primed the carb bowl manually and she started immediately. Grrrrr.. None of the potential problems is a big deal. Coil, Condenser, Fuel Pump, Fuel line blockage, Cruddy jests? But figuring out for sure which one is the problem is bloody annoying!!!!

Funniest "breakdown" yet?..

Just highlighting my incompetence to the world with this post - is that wise? !

Drove Amy to work, nice day for it, and planned pub visit for lunchtime equally making it a no brainer to give her an outing.

On the way from the office to the pub however, she lost all power and gradually ground to a halt right opposite the pub I was aiming at!!

The power loss was pretty much complete, so bonnet up and started some fiddling. Fuel or electrics - wasn't sure but I thought it had to be one or the other. Anything mechanical would not have just stopped her dead like that. Some random fiddling got her going again. For around 500 yards. More fiddling. Another 500 yards, then nothing, no further random fiddling got her going on the third attempt.

Needed to investigate a bit deeper, otherwise I wasn't going anywhere. Figured I'd check for a spark to start with, one plug out, hold it to the engine block check for sparking. The first sign of my problem was the fact that the plug was finger tight. It looked fine when it was out, but I shouldn't have been able to undo it so easily. Checked the other three. Same problem, all loose!!!

Spark was apparent on the removed plug, so put it back firmly where it belongs and tightened up the others too.

All fine.. Doh.. Can't have tightened them up properly when cleaning them off last time a week or so ago. Not sure I totally understand why TOTAL loss and not patchy loss, but either way, happy (if feeling a bit stupid!!)

ACCC Brooklands evening

Another pleasant evening spent at Brooklands. Battery is fully charged now, ammeter is behaving as you'd expect with a 40 mile round trip under it's belt.

Good job too as headlights, main beam and windscreen wipers needed on the way home!

Dynamo replaced and all working again

Refitting was no problem, the dimensions are ever so slightly different so the pulley is pushed forward a touch. So will have to watch for fan belt wear.

Or the next knock on effect of replacing the fan belt which will be the water pump bearing giving up the ghost??!!

Re-wiring turned out to be exactly as described in the various documents and internet articles that I had found. Only issue was that by using the "D" terminal it made the ignition light stay on as described in an addendum at the bottom of this article on the subject. (I have found a few useful tips on the MGAGuru site - thanks from an Austineer!)

But nevertheless, not wanting to follow the advice on that page, I just used the redundant earth terminal as my connector instead. So the regulator is now just a glorified connector block:

New "Dynamator" !

So this is an alternator but built within a shell of the exact style and dimensions of the original Dynamo. The theory being that from a physical point of view it is a very easy like for like swap out.

Therefore the brand name is a "Dynamator".

The re-wiring also looks to be very simple. It has an on-board regulator / cut out so the original Regulator can be bypassed. (or, as in many cases, just re-wired so it serves at a glorified junction box and maintains a relatively original look)

The only complication is that I need to be careful about Positive/Negative earth. Amy would have originally been positive earth, but at some point previously she had already been coverted to negative earth. So I just need to be careful follow the correct steps.

Will aim to get that in this week. Maybe even this evening depending!

Dynamo is knackered!

Took it apart yesterday with my father. His first job was car electrics and he used to refurbish dynamos as a sideline in the 60's! Useful. So he helped me through some diagnostics, cos I had no real idea what to check nor how to check it. 

Firstly, the obvious that even iI could see, brushes looked fine. So that meant that other problems were likely.

Secondly, whether it was charging or not, the bush was extremely worn, the armature was flopping around a bit. All my noises can probably be attributed to that, 

Also, caused by that, the plates on the field coils were worn where the slack had allowed the armature to come into contact. Thus probably overheating and knackering the coils beneath. Bottom line was his opinion was that it was knackered. We did some clean up work and some re-testing and although a magnetic field was being induced, it was not doing it's thing. This indicated that the field coil was probably OK after all and that the issue lay in the armature. Unlikely it was ever going to charge again in it's current state. Even if it did, the bush and bearing would need replacing.

Just to check I refitted back into the car this morning, but sure enough, no change.

I cannot be bothered to try to refurbish it, not worth it. So will order one of these replacement Alternators that are available now. Very reasonably priced, direct replacement in same body, plus built in regulator, so can bypass that (one less component to worry about in future)

Addressing the dynamo problem

Hurst show and the Prom run were both done with no charging happening. Both daytime, no rain, relatively new and little used battery (relatively speaking) so didn't envisage any problem and didn't want to miss either. Any nasty noises had gone away, so even if the brushes had worn down and were doing damage, they had already done their worst, so it was a judged decision.


But it needs to be fixed, so lunchtime today was spent removing the dynamo. Will get the new brushes in and tested over the weekend and hopefully that problem will be sorted. I am not familiar enough with dynamos to know if the commutator is damaged or not, so just keeping fingers crossed really.


But YES I labelled the wires. I was always terrible at that and in my older years I see the wisdom of just a few extra minutes labeling things up rather than foolishly trying to rely on memory or guesswork. Obvious really, but I never used to bother back in the day. Madness.

If that doesn't fix it, then probably get an Alternator (as that would also address the potential issue of the problem being the regulator, as these new Alternators are direct swaps and have a regulator built in).

We'll see  hopefully the brushes are the answer. £5 fix compared to £150 fix!!