Help me with this alternator :(

[00mike00]

I'm not entirely sure why this has been such an problem and i hope i'm not just being dimwitted but i need some clarification with this alternator.
My alternator needs changing, I have the part No. etc and so called my local motor factor. They ordered what was required and when i went to pick up the unit, it was completly wrong.
My alternator is a Bosch 0120 489 780. 14V/65A. You can see here;




This is the one that they ordered...




As you can see, about as different as you could get. Wrong connections, wrong size (Larger body) and power output. (12V 90A)

On second look, they realised i needed the other alternator up on screen but when they went to order it, it wasn't on the shelf and he couldn't find it elsewhere. So i thanked him and left.

I call a company online, based in Huddersfield who take my money for the alternator i gave the part number for and I was due to receive that next day (Thursday 30th). I get a call back about 15 minutes later explaining that particular alternator is not on the shelf...i asked him to see if anyone else had one and he came back to tell me he found somewhere but it will arrive today (Friday 30th).

Today, this is the alternator i received.



Am i being daft or is this not going to work?



Different output, i assume this isn't much of a problem given that it's 12V



I know alternators are all pretty similar but with the issues of connections on the back etc i just want to be sure. I'm not experienced with these units.

Mike

[bortaf]

As long as it physicly fits i don't see a problem ? i cant see the connections on the old alt but there will be a live (the thick wire) and the exciter wire (the thin one) same as on the new one, unless it's a J car you don't say what car it is so not 100% !! most older units have a plug with these wires in it nowdays they tend to be single wires with ring terminals on the end.
In some cases the lower power alts that used to supplyed in cars are no longer serviced, cortinas used to come with 35 amp alts where as sierra (with the same engine) came with 55 amp, stockists don't usually bother with the lwoer amp units so all are now 55 amp (better for the customer and the supplyer), that's often a reason you end up with a higher rated replacement.
One thing, why did you not just find a starter and alt reconditioners and get them to rebuild your unit?
Motor factors are general sales, go to an expert and you usually get better service? for customers i just buy exchange as it's usually on the shelf, if not i get the item rebuilt, it's allways cheaper but sometimes takes 2 days to turn the item around (still quicker than waiting on postage).

[00mike00]

Oct 31, 2014 14:08:09 GMT bortaf said:

As long as it physicly fits i don't see a problem ? i cant see the connections on the old alt but there will be a live (the thick wire) and the exciter wire (the thin one) same as on the new one, unless it's a J car you don't say what car it is so not 100% !! most older units have a plug with these wires in it nowdays they tend to be single wires with ring terminals on the end.
In some cases the lower power alts that used to supplyed in cars are no longer serviced, cortinas used to come with 35 amp alts where as sierra (with the same engine) came with 55 amp, stockists don't usually bother with the lwoer amp units so all are now 55 amp (better for the customer and the supplyer), that's often a reason you end up with a higher rated replacement.
One thing, why did you not just find a starter and alt reconditioners and get them to rebuild your unit?
Motor factors are general sales, go to an expert and you usually get better service? for customers i just buy exchange as it's usually on the shelf, if not i get the item rebuilt, it's allways cheaper but sometimes takes 2 days to turn the item around (still quicker than waiting on postage).

So are you saying i connect live and earth on this alternator, attach connector to the D + and leave the W?
The car is an Opel Monza 3.0L E. 1983
Yeah i'm regretting not getting mine reconned now.

[bortaf]

No earth as far as i know? (later FWD vauxhalls have and earth wire not sure on the earlyer RWD units) alts usually earth through the mount/body, W terminal is for a rev counter (only used for diesel applications) so all there should be is the thick battery+ or maybe 2 of them and the thin exciter wire, the live post will be the thickest and the exciter wire the thinner post, you "may" need to change the wire terminals as they can differ from year to year, i would say from your pic of the new alt that the lower post is the battery and the upper one the exciter wire,
J cars are differant and more complicated hense i asked what car it was

[rodney]

no earths my man , couple a battery lives and the thin signal wire , outputs being higher are fine ,

[00mike00]

The new alternator is fitted, i picked it up friday and just required a ring to spade adaptor.
With the alternator fitted I thought that would cure my charging problem, but sadly no. The reason i changed the alt was because since buying the car, the charging of the battery from alternator has slowly decreased to nothing. After testing what i could, there appeared to be nothing coming from the alternator, so i opted for a new one.
The earth points appear to show a reading so i'm stumped as to what to look at next, i'm not overly confident in this area.

[bortaf]

confused at to what "The earth points appear to show a reading" meens ?
You just put a meter on the live from the alt and an earth and you get a reading (engine running)
lets go back to basics, do you have an ign light on the dash with the ign on possII and the engine off?

[00mike00]

Sorry i know it's hard to get across on a forum. I have an ignition light and battery light on permanently at the moment. 12V appears when testing connections on the back of the alternator and across the battery + and -.

[rodney]

give us a pic of how you have connected the alternater m batt light should only be on with ignition till the engines running

[00mike00]

Will post a photo after work. Cheers

[DavidB]

I fitted an alternator from an MGF to a mk1 MR2 at the side of the road at 2am after a late night in work after my old one seized.
As long as it fits and has a similar amp outage, it should be fine.

[optimusprime]

Volt meter across the 2 battery terminals.
You should expect a reading of 14 volts.
Now switch everything electrical on, ( main beam,blower etc etc) you should not see a drop in the voltage if the the alternator is working and connected as it should be.

Check the connections on the battery,make sure they are clean and tight.
Check engine earth strap.

[bortaf]

Nov 3, 2014 14:26:29 GMT 00mike00 said:

Sorry i know it's hard to get across on a forum. I have an ignition light and battery light on permanently at the moment. 12V appears when testing connections on the back of the alternator and across the battery + and -.

No worries i know it is mate , i try to shave down what i want to say but it usually comes out like i'm being "short" with peeps
If the light is still on when running then the alt isn't charging, as said you should get 14V on a healthy alt which being new yours should be
One thing, you say it requires a ring to spade connector? i beleive the battery light wire should go to the smaller of the 2 posts inside that plastic housing and so would need a ring connector not a spade connector so "if" it has been changed to a spade connector and is now on the mail spade terminal marked + it could be in the wronge place, if it is and earth issue put a jump lead from the battery NEG terminal to the alt body just to make sure

[00mike00]

I had a guy look at the connections and it appears the wire to negative terminal wasn't great, the problem was under the new sheath that someone has put on all the loom. He re-wired that and the connection is perfect. Battery is charging now. Sorry for all the confusion!

[bortaf]

Glad it's sorted and thanks for letting us know the outcome, often we don't get to here the outcome and it does help us in the future to know if we are right or wronge

[nomad]

^ Glad it's sorted.
Just to echo what bortaf said - thanks for the update (party for my curiosity & partly so anyone with the same problem in future knows what fixed it for you)

cheers