Dynamo or Alternator

[PaulJohnson]

Hello everyone.

I have 3 questions here that come from my Dad who would like to replace my Dynamo with A Alternator.

(1) Why did morris fit Dynamo`s to the Morris Minor when a Alternator would have been better?.

(2) Why are Morris Minor wired possitive - earth when all other cars are wire negative - earth?.

(3) my dad wants to buy me a Alternator kit, how easy is it to fit?, I have a radio fitted to my car some one has said that when fitting the Alternator you have to put extra wires in somwhere?.

Hope someone can help.

Paul

[dennis]

hi
well firstb i am pretty bumb when it comes to electricals on cars but i bought an alternater kit and it tool me about 30 mins to do.
basically you take off the old dynamo and coil.
reposition the coil ( i put mine on the inner wing with the terminals pointing to the bulk head for ease0.
ok with the kit you get the brackets ( which i am told are basically from amini) and fit them to the block, put the fan belt on ( this is the same size as the original).
get the right adjustment and tighten.
fix the coil in another position.
in trhe kit there is a wiring harness.
you put the block connector in the back of the alternater ( undo battery trminal).
you then have to connect the brown wire from the new loom to the battery side of the solenoid.
you then take the last 3 connections from the regulater off.
in the kit you have a yellow coloured wire which connects to the original yellow wire from the regulter.
you then change the connection on the coil, to the opposite they were originally.
then start uop and see if the ignition light goes out, if it does ok, if not change the coil wires over.
i would recommend an alternater.
also morris did do an alternater version, i think mainly for the export market, it was called an 11 ac i think.

[rayofleamington]

Hi Paul,
I've had 8 Minors and have never converted one to have an Alternator and have never had a problem.
If you've fitted fog lights, heated rear screen, uprated heater fan etc.. and you do a lot of short journeys with all the extra equipment running plus the lights (eg Winter) then you may find the battery runs low. Otherwise a dynamo is fine!
If your dynamo is worn out, a reconditioned dynamo is inexpensive (probably the same price as an alternator fitting fit, and then you need to buy a good alternator on top).

Re your questions:
1) Alternators are a relatively new invention which is basically better -they were not fitted in the later years of Minor manufacture because the original dynamo design is perfectly adequate.
2) Most cars used to be positive earth - not just the Minor! Negative earth ended up the standard, and most Minors have been changed over but not all. The change is quite easy to do, and is a good idea if you want to fit modern stuff like a radio.
http://www.morrisminoroc.co.uk/technica ... Earth.html

3) If you need to fit an alternator make sure you do a good job. Terminals need to be crimped to a high standard if you want to avoid problems and loose connections. Due to the higher current output of an alternator you need to be sure that you upgrade the alternator output wiring correctly to avoid a fire.

[dennis]

i do a lot of night driving in the winter that is why i changed to an alternater. also i have halogens on the front.
an exchange dyname is £29.50 plus vat.
alternater kit £59.50 plus vat..
the output wire supplied in the kit is correct.

[rayofleamington]

Over winter Gayle's car was only used in the dark and it was nearly all short journeys of approx 1 mile.
The only time I've had trouble was the end of last summer when the petrol pump points failed and I had to start the car every 200 metres but the battery was on its last legs anyway. Since changing the battery (and fixing the pump) it's never run down - even with the occasional 1 or 2 month unused period.

Hi Dennis,
Do the halogen lights draw a lot more current? I have a pair from another car but not used them yet. Did you get frequent flat batteries or was it more a precautionary measure?

[dennis]

hi
well i used to have the halogens working from the dynamo, yes they do take a little more current, i think the halogens have 60/50 on them.
i did tend to have a trouble with the battery runnung down before ( without halogens) in the winter and put this down to the battery which was changed to a new one.
so i would say for me more precautionary, in the winter i do a lot of driving and stop start this sort of thing, so yes more precautionary than necessary.
halogens of course do make a big difference to night driving.

i have another 2 commercials a gpo van and a 1958 pick up, these are still running on a dynamo, but they will stay that way. for purity trying to keep those 2 original as i can.
and even in the cold and not run for a few weeks they give me no trouble at all.

[Willie]

I must agree with 'Rayo' I have never had trouble with a dynamo
being unable to keep the Minor happy. A dynamo is extremely
reliable and the only trouble you are ever likely to have is from
worn brushes........after about 50,000 miles!! easy to replace and
cost about £3 a pair. You must also oil the dynamo rear bearing
regularly. I run halogens and a radio and have no problems.
The usual cause of the battery being unable to supply enough
juice is because it is past its sell by date and does not hold the charge
properly.

[grainger]

hi willie

is changing the brushes on a dynamo really that easy ... you have to open it up dont you ? i ended up buying a reconditioned one instead of attempting it.

cheers
gr

[Cam]

A dynamo is extremely reliable

Yes, I have to agree with Ray and Willie, as I have gone through 3 alternators in 18 months. (duff voltage regulator every time).

The alternator conversion SOUNDS good, but if your dynamo and regulator are working OK then leave them to it - they are more than adequate for the Minor's needs!

[PaulJohnson]

Cam.

The problem I have that because Iam a bus driver the car on a 7 day week in doing short trips 2-3 miles 5 days of the week, also Iam up at 3-4am on mornings and on afternonns coming home at 12am-1am so the lights/heater/fan are always on.

Also the Battery (size 038 ) is only 3 months old but at night when the car is stood at trafic lights the lights on the car + dash go slightly dim and the red light on the dash flickers, so that is why me & my dad thought it would be better to convert the Dynamo to a Alternator.

[rayofleamington]

As far as I can tell, the flickering red light is normal, and I get it even with my recon dynamo, so I'm not sure that it is cause for concern.

Alternators....

and then you need to buy a good alternator on top

Would you trust a scrap yard one or a cheap recon?

3 years ago my Volvo alternator packed up, which cooked the battery and left me stranded needing a recovery truck to get home. To replace both battery and alternator was expensive, not to mention the recovery cost.
Last year I had to replace my Porsche alternator and a genuine part was more expensive than we paid for Gayle's Minor! - So instead I found a cheap recon unit (German & Swedish)...
which was the wrong one when I later tried to fit it, so they exchanged it again.
Needless to say I didn't check the replacement one until the battery failed recently and I found the recon alternator to be faulty. It is now outside of it's 12 month warranty (based on the receipt date, not the date I actually received the part!) Grrrr.
If I'm lucky I can just change the regulator (approx £30) but it's 3 hours work to remove and refit due to the air ducting etc. If I'm unlucky then I'll be shelling out £130 again after less than a thousand miles!!

On Gayle's Minor the dynamo bearings were shot before we got the car. I still ran it for 6 months anyway before exchanging it for only £30.
I'm pretty confident that I may not have to worry about it (except for the occasional drops of oil) for 10 to 20 years.

Dynamos may not be as efficient but due to the simpler technology they seem to be far more reliable and a whole lot better value!!
If it was me I'd stick with the dynamo unless I had a lot of extra current using equipment.

The downside is of course that if your battery is starting to die it will show up a bit quicker, but if you keep an eye on the battery (check water levels every few months and if they regularly go down, scrap it) and watch for slow cranking speed as a hint you are less likely to get caught. Even with an alternator you can't last forever on a duff battery.

Years ago when I had to rely on a Minor for every day commuting in winter I admit that I charged the battery mid-Winter to be on the safe side. That was easy with a driveway as I can stick the extension lead through the letter box and leave the charger under the bonnet overnight - only taking a few seconds, saving 5 minutes for removing the battery.

[Willie]

Changing the brushes is really very simple but,yes,you do have to
remove the dynamo from the car which is not exactly a hard job.
( Your flickering red light at tickover is as it should be, if the tickover
is too fast then the light will not glow,don't worry about it unless
you spend a long time stationary in traffic jams)! Once the dynamo
is off you merely undo two large screws and the end plate comes
off,with the two brushes attached to it.....easy, especially once every
50,000miles!

[Cam]

Paul,

The advantage that the alternator has is that it does charge (slightly) at tickover and has a higher output at lower revs, which was the main reason for me converting.

I also have the biggest battery that you can fit inside the bay! which gave me a days running (50 miles) after my alternator packed up!

So, although dynamos are usually OK and tend to be more reliable than alternators (in my experiance anyway), if I was in your position I would buy a very large good quality battery and a good quality alternator, and like Ray says, don't go for a cheap recon unit as they only seem to last 12-18 months tops.

[rayofleamington]

Well it seems you've got opinions on both sides, and the choice is yours, but if it's just the flickering red light all you're worried about, just remember that most Minors have run happily like that for 30 or 40 (or 50+!) years.

If you really want to upgrade, it should be quite hassle free as long as you don't get a bad alternator.

[PaulJohnson]

Thanks Ray & Cam + everyone for the feedback.

Inc VAT a Alternator kit is £75 from The Morris Minor Millennium Co (Manchester)

Is this price ok?
or for a good/excelent one shall I go to Halfords?.

[Cam]

£71.50 + VAT from the MM centre in Birmingham

£65 + VAT from East Sussex Minors

So, it is in the right ball park.

I have never had an alternator from Halfords as their prices are usually too high, so I can't comment there.

[PaulJohnson]

Thanks Cam.

The prices seem roundabout the same in a way.

I will do some phoning and e-mailing to see which is the best price.

Thanks Cam + everyone on all the feedback that has been sent to all my questions on the diffrent forums.

Paul

[Chris Morley]

Hello Paul,

I'm a firm believer in 'if it ain't broke don't fix it'. A fuctioning dynamo and good battery are fine for a standard car with no accessories. If the radio is the only non-standard equipment fitted I would see if there are any problems before going through the hassle of changing to an alternator. If there are problems get the battery output checked. If it's on the way out then no alternator on earth will make a long term difference.

I had starting problems with my car when I obtained it (although I was never stranded due to that wonderful device called a starting handle). Nothing wrong with the dynamo, simply a combination of a small capacity old battery and a worn out starter motor. I replaced the battery with a Halford's heavy duty type (065?) and fitted a replacement starter motor. The result has been three Winters without any starting problems. That includes heavy ice / snow on mornings when many modern car doors freeze shut ! I work 7 days in a row with a 3 mile trip each way, often starting before 0600. My car is standard except for the Immobiliser which must draw a small current for the LED. I see no need as yet for an alternator.

On cold winter mornings commonsense needs to be applied - start the engine first and rev it at just over 1000 rpm for 15-20 seconds before turning on other equipment. The flickering red light is a design feature - Minor dynamo's won't charge below about 800 rpm I think.

Is it difficult to recondition a dynamo? Usually it's dead easy. If you ever pulled apart a Triang / Hornby model engine from the 1960s and 70s the technology will be obvious . The cap is held on by two long bolts with a screw head which often require a lot of force to loosen. Often you then only need a new pair of brushes, a cloth, some white spirit, a few drops of 3 in 1 oil and a very thin knife blade to restore the dynamo. The copper commutator should be cleaned of all dirt using the white spirit and the insulating segments can be cleared of dirt using the knife (or a razor) down to about 1mm below the surface of the commutator. Do not cut into the insulating material! It probably takes 20 minutes once you've got the cap off. Getting the cap back on without dislodging the brushes is a little bit fiddly. Use a screwdriver to keep them in place.

[PaulJohnson]

Thanks Chris for the Info, you are like me starting work at stupid times!.

I think i will keep my dynamo just at the moment, but when winter comes I think i will change it, this is because in time I will be ading extra`s to my 1970 moggy.

Thanks again to everyone who has replyed.

Paul

[h_____]

Just to add my 2p. I used to commute around the M25 60miles a day in a standard 1098 traveller. In the winter I would need the lights (halogen), wipers, heater and the radio (well not essential). The car had a ammeter fitted. There was no way the dynamo could cope, the car was not designed for this sort of journey, stuck in traffic, in the dark, cold and rain. If you frequently use the car in high load situations then an alternator is good idea, otherwise, like the others say the dynamo is suffecient and reliable and cheap.

I used to have to sit there and turn things off, or rev the engine to keep a bit of charge going back into the battery. I used to know exactly how many amp all the components draw. I found turning the heater, wipers and radio off whilst stationary was suffecient. Although sometimes I would put the headlights on to side beam, and have the radio instead. Its no way to travel!

Now my wife drives the car, short communte through traffic to work all year around. We have an alternator for my peace of mind. They still have brushes to change, and are a less reliable unit, but charge at far lower RPM. We have never had a problem since.


You need to decide for yourself. If you plan to add anything electical, or use the lights and wipers and heater alot when the car is ticking over then an alternator is a good idea. If the car is always going to be moving, it is less of a problem - if at all.