Aux belt "escapes" aside

XANTIA_ML · Post by **XANTIA_ML** » 18 Sep 2006, 06:57

Hi everybody!

Old belt "died".
After replacing I suddenly disclosed that the new one escapes (on the crankshaft's flywheel-to car's outside, on tensioner-inside).

First slipping (4-6mm)-on tensioner even when crancshaft rotated by hand 0.5-1 turn.
It's possible also to see 0.2-0.5 mm axial flywheel's beating and slight tensioner's fluctation when moved by fingers.

What i have replace? Both shows unnormal behavour and each cost appr $80

Please, share yours experience.

Thanks ahead.

citronut · Post by **citronut** » 18 Sep 2006, 08:51

if your belt is moving sideways it is either far to tight or the tensioner bearing is worn out allowing it to kick of to one side
regards malcolm

Kowalski · Post by **Kowalski** » 18 Sep 2006, 08:59

Do you have a disintegrating two part crank pulley?

The crank pulley is made from two pieces of steel, an inner and an outer and rubber between the two parts. They do come apart, check that yours is still intact, it should feel solid.

If it isn't a crank pulley problem, its a problem with either a collapsed bearing on something e.g. tensioner or something is loose or out of alignment, pushing the belt off.

XANTIA_ML · Post by **XANTIA_ML** » 18 Sep 2006, 09:26

The pulley seems OK, tensioner's bearing-too.
I also checked pump and alternator-no signs of loosing.
The question is-can tensioner loose it's aligning in the joint, where spring fitted in?
Did anybody face this problem?
Thanks

Post by **Peter.N.** » 18 Sep 2006, 10:30

Something is obviously running out of line. Are you sure that the alternator bolts tight? If you watch the belt with the engine running, you may be able to see that it trying to run off one of the pulleys before the crankshaft. If the crankshaft pully is the first one that it is trying to run off, its likely the one just before it that is out of line.

XANTIA_ML · Post by **XANTIA_ML** » 18 Sep 2006, 11:15

That's exactly a problem.
The first visible "runout" pulley is tensioner. It is located next after crankshaft.
Additionally-all "working" pulleys are with grooves and idle-without them-so the situation is hard for diagnostic.
It seems I have start replacing from the chippest details and progress according the price...

Ah, I forgot-everything OK when turning crankshaft in opposite direction (of cause by hand

).

Post by **Peter.N.** » 18 Sep 2006, 12:08

Sounds like the idler or tensioner pulley then. Try taking the belt off or slackening it and see if there is any movement in the pulleys.

f00lzz · Post by **f00lzz** » 18 Sep 2006, 19:41

Most likely the tensioner pulley (80 squid) Don't whatever you do.... buy a belt from Halfrauds, they are the WRONG size... far too tight and the reason for the pulley bearings to fail.

XANTIA_ML · Post by **XANTIA_ML** » 27 Sep 2006, 19:45

Hi!
Sorry for late report.

Kowalsky was right: two parts of the pulley were disintegrated. It was impossible "to feel this"-two parts was still coherent, but outer slipped 3-4 mm in engine's direction.

It was difficult for me to detect this-I never seen new one.
Finally after pulley's replacing the belt find his place,

but it was not run on the center of tensioner roller. After roller's replacement ($20 more) belt runs well.
So I think, that tensioner roller's wear out bearing contributed to pulley's fault by creating of axial force.

All the best

jeremy · Post by **jeremy** » 27 Sep 2006, 20:10

I think the theory of the auxilliary belt tensioner causing failure of the bonded crSimply a case of Rubber Fatigueankshaft pulley doesn to work.

Just look at the sizes involved. The bonding of the crankshaft pulley is about 1 inch from front to back (25.4mm), and about 1/4 inch (5mm) thick. Its not there for decoration but to do a job which is damp out crankshaft vibrations - and from the difference in noises from my BX 1.7TD (solid pulley) and ZX 1.9D (Bonded pulley) it does actually make a difference.

The damping is effected by the slight movements of the outer (flywheel) part in relation to the inner (crank) part and I'm sure you can imagine over a high mileage how often they have moved in relation to each other. - Simply a case of Rubber Fatigue!

ball bearings in tensioners have a finite life too - which means that they wear out - motoring is an expensive pastime!

XANTIA_ML · Post by **XANTIA_ML** » 28 Sep 2006, 19:55

It seems-I did not explane myself good-sorry.

Of cause -the main reason of pulley fault if rubber's wear due it's damping activity as You described+high temperature+AC compressor+...

When I told about tensioner roller's contribution-I meant the following: pulley's outer ring slipped to engine direction after disintegration-the same direction belt slipped on the distorted roller with wearied bearing. It means, that there is an axial component of belt tension force and it creates axial stress additionally to tangential. Extent of such contibution-

Hope, now my explanation is more successful (oh, my English

)

Regards

f00lzz · Post by **f00lzz** » 28 Sep 2006, 21:19

XANTIA_ML wrote:It seems-I did not explane myself good-sorry.

Of cause -the main reason of pulley fault if rubber's wear due it's damping activity as You described+high temperature+AC compressor+...

When I told about tensioner roller's contribution-I meant the following: pulley's outer ring slipped to engine direction after disintegration-the same direction belt slipped on the distorted roller with wearied bearing. It means, that there is an axial component of belt tension force and it creates axial stress additionally to tangential. Extent of such contibution-

Hope, now my explanation is more successful (oh, my English )

Regards