Classic cars forum & vehicle restoration.

[1stpop]

I'm fitting an 18acr alternator to my Morris * but have got a little problem! My original pulley - which I need to use beause of the fan - won't fit without taking the alternator fan off. But! my pulley has little fan blades on the back - will this be ok bearing in mind it will also have the big fan attached as well?

I've added a pic

[Phil - Nottingham]

Not quite sure what you mean by the "big fan" is it the rad fan? The alternator must be cooled - if your pulley has blades which provide adequate air flow then it should be OK.

However a reason why an alternators is better than a dynamo is that it suplies charge at lower revs because it has a smaller pulley and so runs a lot faster. If the old dynamo pulley is even slightly larger some of the advantage will lost and you may find the wraning light cominh on at idle just as it should with a dynamo signifying NO charge
_________________
Rover P2
Rover P4
Rover P5 & P5B
Land Rover S2 & S3
Morris Mini Traveller Mk2

[1stpop]

yep the 'big fan' is the radiator fan - and the pulley is roughly the same size as the one which came with the alternator

[47Jag]

1stpop,

I agree with Phil as to your need to have the alternator on a smaller pulley but you are stuck with the fact that the radiator fan is also part of the alternator pulley. Ideally the alternator should be running at double the crankshaft speed but in your case so also would the cooling fan. Not a good thing IMHO. Cooling-wise I think it should be OK as is.

Art

[ukdave2002]

Hi

you need both the alternator fan and the engine cooling fan. I suspect your problem is that you are trying to use an early alternator fan which has a shoulder on? the later fans don't have this shoulder, see pic;



If you use one of these the Morris 8 pulley will fit; see below, you will need to make a small bush (or shim the shaft) as the Morris pulley bore is slighly to large for the ACR shaft.

Dave

[Phil - Nottingham]

It would not be good idea to run the cooling fan at a much higher speed as apart from the noise it will make it may fly apart because of centrifugal force.

Can you fit an electric fan?

It will still be better than a low output dynamo even if run at lower speed
_________________
Rover P2
Rover P4
Rover P5 & P5B
Land Rover S2 & S3
Morris Mini Traveller Mk2

[ukdave2002]

[Phil - Nottingham]

I realised that?
_________________
Rover P2
Rover P4
Rover P5 & P5B
Land Rover S2 & S3
Morris Mini Traveller Mk2

[1stpop]

Not really sure I'm quiet up to making a 'shim' for the pulley shaft but I did realise it was too big for the shaft - lol. I was going to use the pulley and fan off my old (ex) ford pop, but this has a collar already on it which means it wont take the existing alternator fan as well - see pics. Where can I get a 'shim' from so I can just use the originial fan and pulley from my Morris 8. The pop pulley is a little smaller than the Morris 8 - practically the same as the pulley which came fitted to the alternator. Not 100% sure it would keep the alternator cool enough although it does have some cooling fins on it.

[Phil - Nottingham]

The Pop pulley will probably be OK as long as it has got some cooling but be careful with the main cooling fan. If it is noisy then you could try shortening the blades - but you have to be careful to them it balanced/same lenghth.

You could obtain some shim steel which is very thin like feeler guages -(use an old one?) Far better though is to have a sleeve turned up on a lathe.

Another alternative is to tin the bore and/or shaft with solder - how much smaller is it
_________________
Rover P2
Rover P4
Rover P5 & P5B
Land Rover S2 & S3
Morris Mini Traveller Mk2

[1stpop]

thanks for all the advice - forgotten just how usefull this site can be - the fan from the pop is a little shorter than the Morris 8 one so am going to give it a go and I think the fins on the back of the pulley will cool the alternator. The pop pulley is only slightly bigger than the original alternator pulley so charging should be ok and I presume that the fan that goes with the pulley was made to travel at the speed the pulley will be moving?

[Phil - Nottingham]

Seems quite logical - give it go and please report back
_________________
Rover P2
Rover P4
Rover P5 & P5B
Land Rover S2 & S3
Morris Mini Traveller Mk2