Snapped auxiliary belt number 9

Too early to say if it has trashed the head/valves although I'm not hopeful. I dumped the clutch as soon as I heard it snap (maybe before) as they always sheer when coming off the throttle at high rpms. The engine died pretty much straightaway as the belt stopped the crank and I didn't hear any nasty noises. That said, tried turning the crank ever so slightly by hand but the cambelt wasn't moving so I'm guessing it is missing some teeth and has slipped a few. That's nine belts in about 15 months, and even with the protection plate on the crank pulley it finally got me this time

sorry to hear that!

hopefully not done too much damage!

Noooo! Sorry to hear of this, Leight.

You are going to get it fixed, right?

Hope the damage is minimal.

Wow that aux belt is proper mashed up in there. Ditto above hope its minimal.

Oh dear

Let me know if you need another pair of hands to get it fixed.

Chris

Ouch bud. Thats not so good at all.

Ross

Must admit I'm not so sure about it anymore. If I can't find a stronger belt or fully protect the cambelt then I'm not going to rebuild to the same spec, it's just too much to worry about The irony was it went while I was live mapping the car, thought I would likely melt a piston instead

If it fails when lifting off the throttle at high revs, the power of the engine clearly has nothing to do with it (7,500rpm is 7,500rpm, regardless of how much power its giving).

Seeing as the aux belt drives, well, auxilliary items, I still fail to understand how a tuned car is putting any greater strain on the belt. The only difference I can see is that in any given gear, a highly tuned engine will reach peak revs much more quickly.

However, if that was the cause, then the majority of belt failures would occur in 1st and 2nd gears.

I do have a theory - could you check the play in your aux belt tensioner? I reckon that even the slightest amount of wear in the tensioner causes the tensioner pulley to run slightly out of square, which pulls the belt in towards the block (and eventually into the cambelt). My guess is that you may find one edge of what's left of the belt is worn or scuffed.

I know you probably do more flat-out stuff than me (live-map sessions, trackdays etc), but I'm probably doing five to ten times the mileage and I've never had an aux belt fail (although I've had a couple taken off in a fairly sorry state).

There must be a reason - we just haven't spotted it yet.

sorry to hear flea

I have checked the tensioner before and from what I and others can see it is square and has no play. That said, I will be having a real good look this time to see if there is anything remiss. All my belts have come off in the same way, always at the top of the rpm range and when lifting off the throttle. I normally try to dump the clutch to reduce the engine braking but I guess I didn't catch this one.

Sh*t Leight. Sorry to hear that it's broken. When was the aux belt last tensioned?

I can but hope it will just be a new cambelt... or a top end rebuild Think I'll go back to being standard.

Youch!

Hope it's not damaged too much internally Flea, that looks very messy

On Nigel's points above, what about play in the power steering pump bearing or that pulley being slightly out of true on some cars?

Yes need to have a really good look at that Stan. Something to do with the sudden engine braking is causing it to come off therefore anything that it is out line I guess could cause problems.

The way that belt is jammed in there I'd be inclined to expect the worst I'm afraid.

I'd look into getting some form of dividing plate fabricated to keep them separate in the event of a failure

I think he has a plate fabricted as he says in first post. But as Nigel says there must be some unknown factor causing this I would think, beacuse I would think if it was a coupe design fault more people would be suffering form the same effects more often I would have thought ?

I do have a modified pulley, first person to have this from Barbz and I dare say it has helped with the other belts, but it doesn't fully protect the cambelt especially from underneath.

Flea, have you always fitted the same make of belt?

No had quite a few different ones.

When was the last time it was changed and when was it last tensioned?

(apologies for all the questions! )

Crapola hope you`ve escaped with minimal damage.

Is the vibration damper in the crankshaft pulley ok? I`ve seen plenty of Citroen/Peugeot engines with a faulty damper causing the outer section of the pulley to flex.

Baz

Gutted for you mate, I hope it's not too messy

gutted mate. will it be ready for the first outing at combe in april?

damn mate, I can't believe this has happened again....

9 in 15 months? WOW

This may seem OTT to some, but seeing how many times this has happened to you , i would want to try and put an end to it once and for all - this is what i would do.

I would install a small spy camera looking at the belts and then do some high rpm runs on the dyno and watch the footage to see if you can see what the belt is doing during a high rpm run down.

This in my opinion is the only real of having some sort of chance to understand(and see!)EXACTLY what is happening to the belt, otherwise you could just keep ending up guessing and speculating. I know it will be spinning extremely quickly, but you could record the footage and slow it down afterwards. You can buy a small camera kit here for less than a £100 and if it doesnt work, just sell it on or have some fun doing other things with it.....

http://www.wirelesscamera.co.uk/spycam-spy-camera.htm

Very Sorry to hear the bad news!

This is the car that gave/gives coops a real good image!

Are you planning to move onto another car if you put it back to standard and what car?

Sometime before Christmas in November when I lost it on the drag strip at Shakespeare County (did more runs with no power steering ) Normally I replace it and then tension it again after a few miles just to make sure it's on tight.