My gremlins are back

Try changing the condensor I had an intermittent misfire on my '64 Traveller last summer, never died totally - just ran very, very rough and lost power - but only from time to time.....

Took the fuel system apart all the way from the tank to the manifold - no problems. Changed leads, contact breakers - no different. Like all intermittents - it's a pain to track down.

Problem went away when I changed the condensor. Final diagnostic 'hint' was drigint though our local village, big loss of power, followed (some seconds later!) by a noise like a shotgun going off as the condensor chose to work and ignited an eahaust-pipe-full of petrol vapour......

Hope this helps Adrian

I know someone who had a similar problem with an MGB that the car would not restart when hot. When the car was left for 15 minutes or so the car would start. It also would cut out if driving in slow heavy traffic in hot weather. The problem turned out to be the ignition coil and when changed solved the problem.

Hope this helps

Steve

My guess is fuel evaporation. Modern petrol suffers far more than that the car was designed for.

Try insulating all the pipes - but if it's happening in the carb it'll be more difficult to fix. Other way is to convert to a flow and return system for the fuel - that will keep it cooler in the pipes.

I'll second that - I had the same problem with my MGA. New coil sorted it out and when the same thing happened on my MG ZB I just changed the coil on the roadside without even getting my wedding suit dirty. Possibly the same dodgy batch from Moss.

Hi, I would say it is the coil because coils are most liable to fail when hot. I doubt it was eveporation as you would have heard the SU electric pump ticking its head off especially if you had your head under the bonnet. You don't say how old it is so it is worth while checking the distributor for wear by removing the cap and turning over the engine and checking the points gap at each lobe of the distributor. I had this once once and it had baffled a lot of people previously.

Alan (ex minor owner)

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As others have suggested, replace the condenser. In fact, buy two, and keep one in the glovebox (they're cheap enough to keep a spare, but even new ones can be naff out of the box so it pays to get a couple!). If it persists, I reckon fuel starvation is the issue - its not exactly uncommon. Easy cure - insulate the feed, or just buy a heatshield kit from someone like Mr Grumpy (Google it). I have one of his kits and am happy with it.

Mike (owner of, sadly, too MANY sodding Minors :) )

Firstly as you have replaced everything.

Check the point gap it may have closed. This seems the likely cause from your symptoms.

Easily checked by playing a hot air source on it before the engine gets hot. A paint stripper gun is ideal - preferably one with a low heat setting.

The petrol doesn't disappear but evaporates - and the pump then tries to compress that gas. And stops.

I had in the back of my mind Jim checked pretty well everything recently.

But a dwell meter would show up 'your' fault instantly.

Sounds like the classic fuel lock situation. Rover 3500's (P6B?) used to suffer terribly from it.

Either insulate the pipe or run it away from the exhaust so it isn't getting too hot.

I've also seen continuous flow systems fitted that enable air locks to be pumped through so there is no stoppage of fuel. Peter

-- Peter A Forbes Prepair Ltd, Rushden, UK snipped-for-privacy@prepair.co.uk

Dodgy rotor arm.

My dad was a victim of this. First one we got as a replacement was from the AA breakdown man who came out to us and fetched one from a motor factors in Northampton. That got us 60 miles up the A1. At that point, we ruled out the rotor arm and got recovery back home.

Back in the light of day, we found it was a dodgy rotor arm and got another. Second one we got was from a motor factors in Driffield.

Again, it did the same.

Third one, and the one that actually ended up being OK, we got from a guy selling new old stock on Ebay.

As for the condensor, I have had that happen years ago on a Datsun

100A-FII I owned. Set off from Edinburgh, got as far as Coldstream and it packed up. Left it 30 minutes, started it up again and did the remaining journey back to Bridlington without any problem.

Thanks for all the suggestions. It looks as though the consensus is that the problem is in the distributor somewhere. So taking it off will allow me to have a good look for points gap, bearing wear, failing rotor arm and chafed wires under a bright light with a magnifying glass. Then the same with the cap - it was new, but it is vaguely possible that the carbon brush is sticking in its channel. Or a hairline crack has developed.

Then it is back to replacing things. As has been pointed out, a rotor arm and condenser (or two) isn't going to break the bank.

I think somewhere in my collection of "too good to throw away" is an old Imp dizzy, so I might try to find it and see if the condenser and rotor arm are the right type. That Imp always ran sweetly (it got scrapped - before they started being considered classics - after the gearbox gave out) so unless the components have deteriorated from not being used it might be worth trying those old parts as well as buying new ones.

I really don't think it is the coil. I put a new one on in the first set of fault finding, but after I got everything working I tried the old coil again and no fault reappeared. Then I refitted the new one. So my guess is that both old and new coils are OK. I also don't think it was fuel evaporation, because when I was fault finding first time round, after I replaced the float and needle valve the fuel level was always right when I checked, yet still it wouldn't start. As was said elsewhere in the thread, I could hear the pump when it clicked yesterday, and it sounded ordinary, so I have no reason to think that the situation has changed.

The problem is that I can't be at all certain that I can recreate the fault, so it will be very difficult to prove that I have fixed it. But the fault has to be something simple because there is nothing particularly complicated under a Minor bonnet.

The only thing I can think of that I haven't checked before is the earth strap, but judging from the way the engine turns on the starter, this is probably OK. But I will leave no stone unturned this time.

Jim

Ah, you never said that first time!

I used to have a Minor who's pump would click in lieu of a low fuel warning light, but every one I've had for the past 15 years the click means its going to stop in....wait a sec...ooops, too late, its stopped!

I'm with those backing a condenser as culpit. Don't forget that as well as the suspect one in the distributor there is often one on the coil too. (though i would have expected smoke from that failure)

My 2p worth: Fit a new separate piece of wire to link the the coil directly to the distributor.

Not that it helps much but have you an alternator conversion or are you still with dynamo and voltage regulator box?

Roger R

Well no thats used a radio noise suppressor. or are you thinking of a voltage resistor which are not on morris minors.

this is normal for thr MM

The condensor sometimes fitted as a radio interference suppressor is usually connected to the battery supply side of the coil. As mentioned, I would expect fireworks from a failure in that position, but it is possible that at some time it may have been inadvertly swapped over to the contact breaker side of the coil where it would be in parallel with the one in the distributor and subject to considerably more stress than for which it was designed. Temperature related failure would be a significant possibility. But probably in this case there is no capacitor on the coil at all.

Capacitor in the distributor is 0.2 uf 500V rating. Capacitor fitted to coil for RFI suppression typically 1 uf 150V rating.

Quite so, but my recommendation still stands: Make up and fit a new wire linking the coil to the distributor.

Roger R

There is no radio fitted, nor a suppressor on the coil.

I am still using Dynamo and Control Box, but don't really see what difference it makes. The battery is in good condition and the dynamo charges it OK.

Both ends of the coil to distributor wire look in good condition, but it can do no harm to make up another one. Thanks for the idea.

I haven't bought the replacement parts yet, but I took the car for a 5 mile run this morning and it was Ok except the last bit where I was going uphill in 3rd and there were two misfires about 5 seconds apart, but just those two. After that it was OK again. The trouble with something intermittent which is that infrequent is that it will be very difficult to check whether I have fixed it.

Jim

And you do have the wires from the coil to the distributor the correct way in accordance with the polarity of the electrical system.

The Morris Minor was originally a positive earth car so the coil to distributor should be off the positive side of the coil.

If it has been modified to a negative earth system then negative side from coil to distributor.

r

Yes, I worked that out and double checked it when I fitted the new coil, which was conveniently marked + and -

The old coil was less friendly, being marked SW and CB.

Jim

I'd be inclined to chuck out the points and condenser and fit an electronic trigger. Pretty cheap these days. Reversible, too.