Lister Sr3

[John Lewis]

Hi Ive a Lister Sr3 Im currently bringing back to life.

With the help of Blizzard on here I managed to free out the gearbox.

 

But couple of other minor issues.

The alternator seems to be very old and Id like to change it up - so what do I need to look for?

 

And do I need a stop lever cable mounted somewhere is that mandatory?

 

 

Thanks

 

 

Edited December 11, 2020 by John Lewis

[Stilllearning]

About the engine stop cable, having one is just plain sensible. The alternatives, such as scrabbling around under the floor boards to stop the engine in any emergency, just doesn’t bear thinking about. I’m not sure if it’s mandatory, but it’s necessary.

[Tony Brooks]

I don't immediately recognise that alternator but the pulley is  exceptionally small, just what you need on an SR series engine that drives the alternator from the cam shaft. You also seem to have a polly-V belt and not the standard ordinary V belt. That is probably to get it around the very small pulley.

 

You need to make sure that whatever alternator you fit can accept hat pulley and fan. The alternator looks longer than "normal" so it may be a high output type. If so retaining it even if it needs repairing may be a very good move. Perhaps @Sir Nibble can recognise it and give more information. It may be a Bosch 90 amp job.

[fatmanblue]

I would guess that there are many different alternator fitments on SR3 engines - yours is certainly completely different to the one I had.  Probably best to identify the alternator on there now and attempt to replicate the fitment size.  It has a poly-V belt - so not that old?

 

As always with SRs (and I presume STs), the alternator pulley is on the camshaft so spins at half engine speed.  You need a big pulley on the engine and a small one on the alternator, which may explain the poly-V belt you have.

 

(as Tony posted whilst I was typing)

Edited December 11, 2020 by fatmanblue

[David Mack]

Belfast's ST3 has a large pully - something like 10" diameter - on the camshaft to drive the alternator (through a standard V belt). Judging by the alternator mounts I think this is a later alteration to the original.

[Sir Nibble]

5 minutes ago, fatmanblue said:

I would guess that there are many different alternator fitments on SR3 engines - yours is certainly completely different to the one I had.  Probably best to identify the alternator on there now and attempt to replicate the fitment size.  It has a poly-V belt - so not that old?

 

As always with SRs (and I presume STs), the alternator pulley is on the camshaft so spins at half engine speed.  You need a big pulley on the engine and a small one on the alternator, which may explain the poly-V belt you have.

 

(as Tony posted whilst I was typing)

That's a CAV AC5. Not a particularly high output machine in its 12V incarnation. Shaft size is unusual at 19mm so you're not going to swap the pulley to just any old alternator.

[Tony Brooks]

27 minutes ago, Sir Nibble said:

That's a CAV AC5. Not a particularly high output machine in its 12V incarnation. Shaft size is unusual at 19mm so you're not going to swap the pulley to just any old alternator.

That confirms my fears re the shaft size.

 

it also explains why I did not recognise it, I dealt with the military version with the tin end cover and huge multi-plug connector on it.

Edited December 11, 2020 by Tony Brooks

[John Lewis]

20 hours ago, Sir Nibble said:

That's a CAV AC5. Not a particularly high output machine in its 12V incarnation. Shaft size is unusual at 19mm so you're not going to swap the pulley to just any old alternator.

Cheers all, for me the issues is re-connecting these two boxes that came with the alternator.

We quickly whipped them off when trying to get it bled and re-running.

 

Could anyone identify what they do?

I have the original user manual for the SR3 and it does show a wiring diagram,

But I would prefer to just keep it simple and go with an alternator that goes straight to the batteries / split charger.

 

Could I take off the pulley on this CAV one and put on a more modern design?

 

Pics attached for ref.

 

Edited December 12, 2020 by John Lewis

[Alan de Enfield]

Could be 'way off' but the aluminium thing look like a voltage regulator from the days when Dynamos were used.

 

The blue thing looks like a split-charge unit

[Sir Nibble]

The blue thing is a split charge diode, silver thing is a type 440 transistorised regulator. State of the art when I started in 1974!

I will scribble a connection drawing for you over the weekend.

[Alan de Enfield]

8 minutes ago, Sir Nibble said:

The blue thing is a split charge diode, silver thing is a type 440 transistorised regulator. State of the art when I started in 1974!

I will scribble a connection drawing for you over the weekend.

That makes a change - I was correct.

Remember the regulator well - it was always screwed onto the firewall around the dynamo 'side of the engine'. 

[Sir Nibble]

22 minutes ago, Alan de Enfield said:

That makes a change - I was correct.

Remember the regulator well - it was always screwed onto the firewall around the dynamo 'side of the engine'. 

It's an alternator regulator frequently screwed to a "control board" incorporating a main fuse and ammeter shunt. In the old six diode systems they were accompanied by a massive cut out very similar to a dynamo system.

[Alan de Enfield]

8 minutes ago, Sir Nibble said:

It's an alternator regulator frequently screwed to a "control board" incorporating a main fuse and ammeter shunt. In the old six diode systems they were accompanied by a massive cut out very similar to a dynamo system.

 

Ah, thanks, I was almost correct then (no cigar this time)

[John Lewis]

funny video here explains Regulator:

 

[Tony Brooks]

1 hour ago, Sir Nibble said:

The blue thing is a split charge diode, silver thing is a type 440 transistorised regulator. State of the art when I started in 1974!

I will scribble a connection drawing for you over the weekend.

This is the diagram I have

 

 

Might save @Sir Nibble drawing it out for you.

8 minutes ago, John Lewis said:

funny video here explains Regulator:

 

For dynamos. It also has a cut-out in it. By and large alternators do not need cut-outs and part from some very early European and Jap alternators the regulators are always solid state.

[Sir Nibble]

Wiring broken into stages. Digrams show terminal end of the alternator from above. I might  have the positions of the main terminals swapped but they're marked.

Positives and negatives.

  

Alternator field.

 

Warning light. This is not an optional luxury, the system needs it to work.

 

[John Lewis]

Thanks Mr Nibble, I'll try and digest that.

 

And see if I have warning light option on key switch,

 

 

Would you recommend I keep it?

[Sir Nibble]

1 hour ago, John Lewis said:

Thanks Mr Nibble, I'll try and digest that.

 

And see if I have warning light option on key switch,

 

 

Would you recommend I keep it?

The switch doesn't have a WL terminal, it just needs a supply with ignition on. Should you keep it? If it works and your batteries stay charged, yes. If not we can look at it again.

[John Lewis]

One last question Senior Nibble,

 

Theres no isolator switch in the diagram. Would this still work if I put an isolator along the positive lead, before batteries?

 

Nice one. ☝️ 

[Tony Brooks]

36 minutes ago, John Lewis said:

One last question Senior Nibble,

 

Theres no isolator switch in the diagram. Would this still work if I put an isolator along the positive lead, before batteries?

 

Nice one. ☝️ 

Question is unclear.

 

You have two positives running from diode to the battery banks. Where do you think you might put the isolator?

 

I think you need two, one in the feed to each bank but the diagram is just for charging and does not show any feeds for your domestic or engine circuits.