Tightening Alternator Pulley?

[Lon nan Gruagach]

Hammers and bearings are not good bedfellows, not by a long chalk.

 

[VicS]

Indeed, hence the question. Where can I get a 24mm socket with external flats?

can you explain why the suggestion to hold the pulley with an old belt or similar while tightening nut with an ordinary socket won't work. Is the pulley not keyed to the shaft?

 

[RobbieW]

...Is the pulley not keyed to the shaft?

On mine, a Balmar unit, the pulley is not keyed to the shaft. I now have poly-V belt so using one of those constrictor tools also works but, as a time served mechanical apprentice, using one still feels wrong

 

[RobbieW]

Faced with a very similar problem, I managed to find an offset 24mm ring spanner that fitted inside the pulley recess

btw, remembered that the tool I found was in a Spanish ferreteria, I couldnt find the same thing in UK tool stores. It says its an IRIMO tool on the shaft. As the OPs boat is in the Canaries, perhaps a good local tool shop is the place to go. In the Irimo catalog, its described as an L Type socket wrench

 

[RichardS]

On mine, a Balmar unit, the pulley is not keyed to the shaft. I now have poly-V belt so using one of those constrictor tools also works but, as a time served mechanical apprentice, using one still feels wrong

I know how you feel! I stripped down my Jaguar top end a couple of weeks ago and the 4 overhead camshaft sprockets are not keyed to the end of the camshafts, it's just a taper. Just imagine the force on that taper with each cam opening 8 valves. I could not turn the cams by hand. Incredible!

Richard

 

[rogerthebodger]

can you explain why the suggestion to hold the pulley with an old belt or similar while tightening nut with an ordinary socket won't work. Is the pulley not keyed to the shaft?

That would be my question also at I suggested in post #6, having used that technique numerous times even without a keyed shaft throughout my time working as a Mechanical Engineer.

 

[Spi D]

Same sort is used for Strut Towers on cars (top of McPherson suspension, accessible from engine room). Available from car tool shops.

 

[RichardS]

That would be my question also at I suggested in post #6, having used that technique numerous times even without a keyed shaft throughout my time working as a Mechanical Engineer.

You can hold the pulley with a belt as tightly as you like but if the shaft is not keyed it (the shaft) will turn when you try to tighten the bolt.

Richard

 

[prof pat pending]

Not strictly true, although I see where you're going with it.

Even at finger tight, you are starting to apply friction to the assembly, the more you tighten it, the more friction, giving you the ability to tighten it further.

 

[RichardS]

Not strictly true, although I see where you're going with it.

Even at finger tight, you are starting to apply friction to the assembly, the more you tighten it, the more friction, giving you the ability to tighten it further.

You could be right although I'm surmising that the alternator has an allen socket on the end because friction alone won't do the trick. Perhaps worth a try though as there's nothing to lose.

Richard

 

[Lon nan Gruagach]

While it is possible (and maybe probable, havent done the math on relative friction and taper ngle of thread vs taper), especially if you lubricate the thread (as you should anyway) to tighten a nut on a taper shaft without clamping the shaft itself.... (way to long a sentence!) The drawing submitted shows no taper..... or woodruff key for that matter, which beggars the question: what stops it spinning anyway...

 

[lw395]

You should find that holding the pulley works well enough.
Wrap a bit of old belt around in and clamp the ends in a vice?
Failing that, drill and tap the pulley where D is on the diagram, then add a grubscrew.

Or mill a couple of flats on the inboard end of the pulley?
Or grind a couple of flats on the socket.

 

[rogerthebodger]

Same sort is used for Strut Towers on cars (top of McPherson suspension, accessible from engine room). Available from car tool shops.

Easy to modify a normal long socket with an angle grinder to make this type of special sockets and will be a lot cheaper as well.

 

[Daydream believer]

Check rotation of pulley. If it rotates against the thread rotation the weight of the alternator under load should tighten it for you as you use it , provided you get a bit of friction to start with

 

[VicS]

Check rotation of pulley. If it rotates against the thread rotation the weight of the alternator under load should tighten it for you as you use it , provided you get a bit of friction to start with

In Nigels case the engine rotates clockwise ITYWF. therefore it would require a LH thread on the alternator shaft to have a tightening effect.

 

[prof pat pending]

While it is possible (and maybe probable, havent done the math on relative friction and taper ngle of thread vs taper), especially if you lubricate the thread (as you should anyway) to tighten a nut on a taper shaft without clamping the shaft itself.... (way to long a sentence!) The drawing submitted shows no taper..... or woodruff key for that matter, which beggars the question: what stops it spinning anyway...

You'll probably struggle with that calculation TBH....the shaft on said alternator will be straight

 

[prof pat pending]

I suppose you could just take the word of an alternator supplier
http://www.powermastermotorsports.com/082__Pulley_changing_instructions.pdf

Note this is for a race spec alternator with a smaller diameter shaft and a lighter housing making it generally more fragile than the standard off the shelf item.

 

[nigelmercier]

You need what's called a pass thru socket set ...

This may work, if I can find one in the UK:
http://www.kmart.com/gearwrench-1-2...-00960488000P?prdNo=1&blockNo=1&blockType=G1#

 

[prof pat pending]

You'll need a special ratchet to go with that

 

[prof pat pending]

Full set, including a 24mm socket
http://www.chainreactioncycles.com/..._QrM7Ip7tf3i5aptGpN_saAq868P8HAQ&gclsrc=aw.ds