Garage bent my valves during a cambelt change - advice please

Heh - see my question of 24/03 :-)

If the battery has enough to run the electronics but not the starter, then yes, it will run with no alternator. There should be a battery light coming on if the alternator is dead though. (although it didn't work for me :-( ).

cheers, clive

nafuk ( snipped-for-privacy@btinternet.com) gurgled happily, sounding much like they were saying :

Yes, but not for very long at all. You'd also have the charge light on all the time.

If the battery starts out fully charged the car will run for all the daylight hours without any charge from the alternator. If the battery is so flat it needs a jump start then he could be correct. But then *he* should be making sure this isn't happening with the new battery they fitted as it will knacker it.

Some don't believe me but I'd runa car days at a time without a working alternator but I doubt a jump start would be enough to charge the battery enough.

It amazes me how many people replace the battery when the alternator has gone bad then find they have to replace the alternator.

How was the bold sheared off? Has the alternator actually been checked to rule out damaged wiring?

Not sure how the bolt was sheared off. I'm assuming it was bumped when the engine and gearbox was removed. Not sure about damaged wiring, they just told me the alternator was faulty.

Thank you

But that's exactly how they can fail. When a voltage regulator goes, it just goes. Same for a diode. They either work or not, there is no inbetween.

Yes until the battery goes flat.

I believe you. On an old Nissan I had, I got nearly a weeks commuting.

Not so. The regulator can fail so it turns the alternator hard on - I've had that. One or more diode can fail and the device still produce an output. What happens with this is the short circuit diode draws current with the engine stopped and flattens the battery.

Dave Plowman (News) ( snipped-for-privacy@davenoise.co.uk) gurgled happily, sounding much like they were saying :

Cobblers.

Once upon a time, perhaps. For an old-tech diesel, quite possibly - if use of brake lights and indicators is kept to a minimum.

For a modern motor with umpty ECUs? Not a chance.

A few years ago, we had some charging problems with one of our 2cvs - no electronic ignition, just points. We got about 50 miles before it started misfiring as we braked, or missing in time with the indicators. That on a decent-sized near-new battery, too.

Adrian ( snipped-for-privacy@gmail.com) gurgled happily, sounding much like they were saying :

Oh, yes, on another occasion, the alternator belt snapped on my CX GTi. That got 10 motorway miles to my destination, restarted OK, then got about

So if the tyre blew out 5 days later you'd assume that was their fault?

Without some evidence it was their fault either approach sounds like a waste of money. What did the gharage who changed the alternator find wrong with it?

The alternator has not been changed yet. They maintain that both the battery and alternator came to the end of their life whilst at the garage. Would you be happy with this reasoning?

When driving with the faulty alternator, when the revs droppped, the warning light scame on. After jump starting the car ran fine even with lights on. From the above comments does this mean that the alternator is ok, since some people are saying the car will not run with a faulty alternator (and some are saying it will run).

Thank you

nafuk ( snipped-for-privacy@btinternet.com) gurgled happily, sounding much like they were saying :

Yes.

Batteries really don't like sitting flat. If it sat around untouched, the battery'd soften up a bit anyway. If it's then run without charging, that'll also not help. Add in a battery that isn't in the first flush of youth, and I wouldn't be surprised if it was all the final straw. To be honest, I wouldn't get exercised about the battery - unless it was near-new beforehand. They're effectively a consumable.

The car _will_ run without charging, but only until the battery runs out - the debate is over how long that'll be...

If the charge light was on, then the car thought it wasn't charging properly. If it wasn't on, that doesn't mean it WAS charging properly - the only way to be sure is to get a multimeter on it.

That's because of the 3000w sub woofer you've got cut into the back seats ;-)

adder1969 ( snipped-for-privacy@yahoo.co.uk) gurgled happily, sounding much like they were saying :

A sub doesn't tend to add a lot to Radio 4...

The old grey van doesn't even have a solenoid for the starter - you pull a bit of wire tied to a lever sticking out of the motor. Yes, that's how it left the factory... Yes, 12v + alternator from the factory...

You know the size of the battery and the power consumption of engine electronics and fuel pump etc?

Obviously using any accessories will effect things, but basic petrol electrics don't use a huge amount.

Just how much current do you think an ECU uses? You carry around something bigger than a car battery for your laptop? ;-)_

You had another fault. Unless, of course, the best average speed the 2CV can manage is 5 mph. Or it had a crap ignition system - modern ones aren't so voltage dependant.

However, the actual time is irrelevant. Any car will run for an appreciable time with no output from the alternator if the battery is in a good state of charge. Certainly hours rather than minutes, if you minimise other loads.

I was never brave enough to try more than 1 day, but for a while I ran my Mk1 Golf with the alternator disconnected and charged the battery each night- about 26 miles commute in traffic- and it showed no signs of failing.

On Apr 3, 11:18 am, "Dave Plowman (News)"

Seems like one for mythbusters. ...or a new pantomime...