Lucas A127 squeak

[frangar]

Hi

 

I've got a Lucas (well a clone of one!) A127 70 amp fitted to my JP which seems to have developed a squeak....I changed the belt just before we set off for this years chug and all was well.....then it started to squeak...no worries I thought...the belt has stretched...so I retensioned it and tried again but it seems to keep coming back.

 

I've spun the pulley on the alternator by hand and it turns fairly freely with just a little float but no lumpy bits...the tension is fine on the belt and the squeak seems to be worse when the load from the alternator is about half or less...when it's working flat out its fine.

 

As we need to nip out tomorrow in a hire car to do a site visit for work I'm very tempted to try a track a spare unit down either in leicester or Nottingham...I do have a spare onboard but it's only a 55 amp unit and as we are away for the summer it might be better to be safe!

 

So just wondering what others think?...might it be bearings?...my other unit before this one was a genuine lucas a133 which lasted forever.....in fact I only changed it as a preventative measure for the current one....and sold it on eBay! Perhaps I should have kept it!

 

Does anyone know of a good alternator place in either in the Leicester, Nottingham, Newark area?..I've had a google but personal recommendations are much better!

 

Cheers

 

Gareth

[Wrinkley]

My Leece Neville does the same as yours. It almost seems like its wheezing. Replaced belts, sprayed with belt dressing, adjusted, all to no improvement. I took the end cover off had a look inside at the brushes blew some dust off and put the cover back. The noise stopped but after about 20hrs use is now back again.

[bigste]

Don't over tighten or you'll mess up the bearings. You can buy an aerosol of belt dressing to stop the squeak from all good bearing stockists or fleabay.

[frangar]

Right some further tinkering has revealed the following.....

 

The belt just runs round the outside of the flywheel which although has been fine for the past 20 plus years it seems the new belt has left some rubber there which wasn't there before...possibly as it stretched.

 

I've retensioned it again and it now seems fine....although I suppose I won't really know till it's been running all day if the bearings are failing as they get hot....I must say the noise was more like a loose belt than a failing bearing....the belt is now pretty tight.

 

I think some of the problem might have been a slipping belt, due to the high gearing from using the outside of the flywheel it can make the alternator work pretty hard even at low engine revs.

 

Anyway fingers crossed it was just a combo of new belt and rubber laid onto the flywheel....

 

If anyone has more thoughts then please fire away....I still might look for another alternator just to keep as a spare for the spare.....

 

Cheers

 

Gareth

[Paul's Nulife4-2]

Hi ya.

Just to ask the obvious for elimination purposes.

Have you checked the Water pump, Any Slave pullys & whatever else the belt goes around for squeaks, Dust, marks ?.

 

Editcross posted with above

Edited June 8, 2014 by Paul's Nulife4-2

[frangar]

Don't over tighten or you'll mess up the bearings. You can buy an aerosol of belt dressing to stop the squeak from all good bearing stockists or fleabay.

I've still got about an inch of play in the midpoint of the belt....I don't think it helps having no groove in the flywheel for the belt to sit in so it walks around a bit....I might try some belt dressing though.....perhaps my new Fenner belts aren't as good as they used to make!

 

Hi ya.

Just to ask the obvious for elimination purposes.

Have you checked the Water pump, Any Slave pullys & whatever else the belt goes around for squeaks ?.

The belt just goes round the flywheel and the alternator.....no fancy pulley driven water pumps! I've also run the engine with the belt off just to check it wasn't anything else like the injector pump drive.

 

It's the trouble with old engines....you get paranoid when a new noise occurs!

 

Cheers

 

Gareth

Edited June 8, 2014 by frangar

[MtB]

The angle of wrap of the belt around the alternator pulley is important where slippage resistance is concerned, and with the belt around a big flywheel the pulley-wrap angle must be pretty small.

 

Still doesn't explain why it has been fine for the preceding 20 years though.

 

MtB

[frangar]

The angle of wrap of the belt around the alternator pulley is important where slippage resistance is concerned, and with the belt around a big flywheel the pulley-wrap angle must be pretty small.

 

Still doesn't explain why it has been fine for the preceding 20 years though.

 

MtB

It's funny but judging from the rubber left it seems to slip most on the flywheel rather than the pulley....I guess it's because it's running flat on the flywheel face so doesn't have any wedge effect.

 

The belt I took off doesn't have any marks on it and I can't remember who supplied it...I think it would have been Fenner as well...I agree it's most odd how it's been fine and now it's not which does make me think that it might be the bearings protesting when they get warm....at least A127's are pretty cheap and hopefully easy to get....one of the reasons I used it rather than anything more esoteric!

 

I'm going to try to track down another unit today so that should ensure that the fitted one will last forever...of course if I don't get one it will fail tomorrow!

 

Cheers

 

Gareth

[bizzard]

If it starts squeaking again just sprinkle a little water on the belt whilst the engines running. If the squeak stops its the belt.

[frangar]

New alternator sourced and fitted....it's a lot smoother than the (not so) old one...still have a slight squeak which I'm putting down to the belt at lower engine rpm's...I may try some belt dressing if I find some on our travels... I know Toolstation do it. I don't think it's helped by the JP not being the smoothest rotating machine so the belt is snatched a fair bit.

 

I'm beginning to think that even branded belts...Fenner in this case, aren't made of the same material as they used to be....it does feel a bit "harder" which although I suppose means it lasts longer also means it doesn't seem to grip as well.

 

I will post back if there are anymore developments.

 

Cheers to everyone for their advice.

 

Gareth

[MtB]

You might find one of those 'segmented' belts designed to wrap snugly around very small diameter pulleys grips slightly better.

 

MtB

[Proper Job]

There's a really good little pully, belt size, wrap angle calculator here: http://www.csgnetwork.com/pulleybeltcalc.html

[16csvt]

Might it be possible to convert to a 'poly-Vee' belt?

A conventional belt will surely not drive particularly well on the periphery of a flywheel.

Is the flywheel crowned at all (to take an old fashioned flat canvas belt)?

A polyvee might ride a crown quite well.

Just my two pennyworth.

 

Regards to all

 

Kevin

[Sir Nibble]

Squirt water onto the belt with the engine running and if the squeak temporarily vanishes it's the belt. Give the pulleys a nice clean and rough up.