noisy bad fitting belts

B-Hive · Post by **B-Hive** » Mon Sep 29, 2008 9:32 am

hi all

to sum up an issue I'm having with poor fitting alternator/aircond drive belts,,

can anyone tell me whether these belts have to be genuine. I ask cos the generic slotted belts that have been on my car and another doner vehicle both seem to not quite fit centre on all the pulleys. These belts seem to like to sit off centre towards the outter of the main pulley and alternator yet want to sit on the inner bias of the air con pulley. Incurable squealing belts and general noisy operation will be the symptom if setup otherwise. Also all belts I have examined have been stressed or slightly mangled on the inner edge. Having said that, this sort of damage is most likely to be because the belt actually touches the tensioner pulley, and this could be in the way owing to the HP pump belt being generic and perhaps too long.

Has anyone else had issues with off the shelf belts in an petrol aircond BX?

BTW Margot is having quotes done this week to pretty up the mucho badly faded roof paint.. Its fun to be able to focus on the cosmetics now the main sorting is largely done.

Thanks

Jaba · Post by **Jaba** » Mon Sep 29, 2008 10:31 am

I presume you are talking about the 4 groove alternator/compressor belt.

A possible explanation is that the rubber mounts for the compressor have worn allowing the compressor to move slightly out of line.
The rubber part of these mounts or top hat bushes does go oval with time. You can put it right for a while by turning them round 180deg.

You should fit a shorter belt if it is actually touching the HP belt pulley.

DavidRutherford · Post by **DavidRutherford** » Mon Sep 29, 2008 11:00 am

Jaba wrote:A possible explanation is that the rubber mounts for the compressor have worn allowing the compressor to move slightly out of line.
The rubber part of these mounts or top hat bushes does go oval with time. You can put it right for a while by turning them round 180deg.

Unless the petrol arrangement is radically different from the Diesel, the compressor is hard mounted on the sump, and there is no rubber in there anywhere....

Sounds to me like you have 5-rib pulleys with a 4-rib belt on them.

Jaba · Post by **Jaba** » Mon Sep 29, 2008 11:45 am

Yes, some sumps have oversize compressor mounting holes and rubber coated metal bushes are used together with and earthing strap.
Suppose it gives a bit of vibration and temperature isolation.

Petrol engines usually have 4 rib pulleys.
So let us have a bit more info on what Margot actually has.......

Kitch · Post by **Kitch** » Mon Sep 29, 2008 1:23 pm

Brand of the belt won't make a difference in reality. There are around 6 different manufactuers of drive belts worldwide, but over 100 different brands, including genuine.

You do the maths

Post by **mat_fenwick** » Tue Sep 30, 2008 1:11 am

Same brand but same quality???

I used to work for an automotive manufacturer who made OE parts for the engine production line, OE spare parts and autermarket parts. Whilst the first 2 catagories were 'officially' the same, there was a difference and OE spares tended to get the 'seconds' in terms of quality. The argument being that the implications of a part failing after a garage had fitted it were much less severe than stopping or slowing down the production line at the engine factory.

Aftermarket parts were a different kettle of fish, although made by the same people, in the same factory, on the same machines, costs (and corners) were cut wherever possible as there was no OE standard that had to be adhered to.

I have had 2 problems with pattern V belts in changing perhaps 20-30 belts. On my BX I put on a new HP belt which squealed no matter how tight the tension, only when I replaced it with a genuine one did the problem go away. I've also had a similar problem with the van where I would tighten the belt one evening, next morning it would be slack again and squeal. I ran out of adjustment which resulted in the pattern belt slipping and snapping before I could get a genuine one...after 3000 miles the proper VW belt seems fine without retensioning once and also sits better in the pulley groove than the pattern one. So profile and/or rubber composition could be an issue?

B-Hive · Post by **B-Hive** » Mon Oct 06, 2008 12:11 pm

thanks guys

I am running 4 groove pulleys and 4 groove belts, although I can live with the current level of roughness and din, i feel this will be short lived within the next 500k.

HP v belt giving out occasional squeal again and main pulley/alternator air cond giving out a sound similar to rough bearing. Like is say i expect it to relapse but we'll see. To prove that it is the belt i have run the car and rubbed soap into the belt, then its super quiet (for a little while at least).

whilst i have your attention, what would most likely be the cause of intermittent and rapid tick time. For alot of the time, tick time is quite okay but (especially with greater pressure demands) the pump/regulator will cut in and out very rapidly..literally on/off/on/off/on/off. I think i have air in the system, would this be the main cause? I have tried bleeding it but not sure I'm doing it right.

Accumulator is okay (maybe

)