Another snapped timing belt!

On the way home from work Tuesday morning the bloody timing belt snapped again! The problem started here:

http://www.landyzone.co.uk/lz/f48/timing-belt-riding-over-shredding-274950.html

And the new belt has just snapped too! Can't see any wear on the belt and all the pulleys are flush and no play. What could have caused it this time? It's a perfect conditioned belt snapped cleanly...







I took great care and it run best it ever has. Then without warning it snapped as clean as this - what could have caused it this time?

Cheers guys!

I cant answer that mate but sorry to hear your still having trouble with it ;(

you use a good quality belt?

that one got signs of shredding?

tensioner spinning ok?

Pulley and tensioner all as new (I'm gonna replace them again tho) no sighn of rubbing it still looks like new! The belt was a £10.50 unbranded one. I was expecting a dayco belt but I received an unbranded one (prob my own fault). I had to fit it as I needed to get back on the road ASAP as it's my daily driver. It was running so good too! It's bent pushrods and snapped an exhaust rocker but cam sliders look intact thank god!

Luckily I can now do this with my eyes shut iv done it that many times lol.

My bet is a bad quality belt?

Littelwill said:

I cant answer that mate but sorry to hear your still having trouble with it ;(

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Thanks littelwill your comment is much appriciated.

toms3 said:

Pulley and tensioner all as new (I'm gonna replace them again tho) no sighn of rubbing it still looks like new! The belt was a £10.50 unbranded one. I was expecting a dayco belt but I received an unbranded one (prob my own fault). I had to fit it as I needed to get back on the road ASAP as it's my daily driver. It was running so good too! It's bent pushrods and snapped an exhaust rocker but cam sliders look intact thank god!

Luckily I can now do this with my eyes shut iv done it that many times lol.

My bet is a bad quality belt?

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says it all mate. you took a risk, and got bitten. get a proper one

trax said:

says it all mate. you took a risk, and got bitten. get a proper one

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Very true, Lesson to everyone - buy the best belt you can!

I Diddnt have much choice as I needed to be on the road. I hope thats all it is that caused it.

Has it been known to happen before with cheap belts?

Have you got a rough or sharp edge on any of the teeth (pump / cam / crank)? Other than that if the rest of the belt is perfect and showing no damage then it looks like a poor quality belt failure.

The only reason a belt would snap like that is if it was tensioned too tight. How did you tension it?

Ian46 said:

The only reason a belt would snap like that is if it was tensioned too tight. How did you tension it?

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Tourqe wrench I can't remember what mesurement but I got the setting from the internet.

Don't fit crap belt's dude, not worth it.
To me that looks like something stopped suddenly and the belt was pulled apart. It might not be just a cheap belt issue, I wouldn't expect a cheap belt to do that.

Could this and your 50mph limit be linked? Not entirely sure how!? Throwing the idea out there...

nobber said:

Don't fit crap belt's dude, not worth it.
To me that looks like something stopped suddenly and the belt was pulled apart. It might not be just a cheap belt issue, I wouldn't expect a cheap belt to do that.

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I was thinking that too, but the pulleys are all free spinning. I'll fit a new dayco kit and hope for the best!

Could a pulley momenteraly lock up?

I do remember struggling to get the stub that goes into the tensioner in as the belt was very tight and to be honest on its loosest setting and that was still tight. The torque wrench was probberbly doing nothing to be honest.

Should the tensioner just slip onto the peg with no belt tension?

Check the cam woodruff key. I had a cam follower spin, stop the cam, which in turn sheared the woodruff in the process of snapping the belt.

One of the cars follower set screws had fallen out of the block!

It does seem strange that your limited to 50mph and keep having belts snapped. More going on with the engine that we think?

toms3 said:

The belt was a £10.50 unbranded one.

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Oh dear.

Change from £20 would have got you a Dayco delivered. I cannot stress enough how important it is to use good quality parts for critical parts, and I suggest stress using quality parts for non critical parts too as you will probably be buying them again soon.

Nowadays there is no such thing as cheap, just rubbish.

toms3 said:

Could a pulley momentarily lock up?

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Now, there is a possible issue with your engine - several things worth checking, one is if your valve clearances for example are way out, or the stem caps have worn through and jumped off it is possible at higher revs for the rod to jump the recess in the tappet it then sits high on the edge of the tappet, when the valve is next actuated the rocker slams down on the rod sitting high on the tappet it tried to drive the valve too far, it can then hit a piston or bottom out on the spring, the sudden shock gets transferred back, jars the camshaft and then the belt. This happened to a friends 200tdi, but he hadn't seated the rod properly on reassembly. It was discovered by slowly turning it over by hand with the new belt installed and every time a valve moved there was added resistance as we moved past that point, it did keep going round but was enough to make you think the added stresses etc could eventually kill belts.

Could also be a foreign object in the engine somewhere, did you use any force on the new belt, could be the old one died of natural causes and the new one was subjected to cruelty or it's just cheap.

Check the two large pullies carefully for any contamination in the grooves. Also a land rover mechanic that delt with nothing but land rovers told me, "If you change your timing belt, change the two large pullies as well, as they wear along with the belt then a new one doesn't fit properly."
I don't know how true this is but the effort required to get to the belt its can't be a bad thing.
I hope it may have shed some light to your problem, and wish you well fixing it.
P.S. As others have said. Cheap belts are false economy.

Zuggy said:

Check the two large pullies carefully for any contamination in the grooves. Also a land rover mechanic that delt with nothing but land rovers told me, "If you change your timing belt, change the two large pullies as well, as they wear along with the belt then a new one doesn't fit properly."
I don't know how true this is but the effort required to get to the belt its can't be a bad thing.
I hope it may have shed some light to your problem, and wish you well fixing it.
P.S. As others have said. Cheap belts are false economy.

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you cant really change the cam pulley very easily as you would then need to retime the cam.

Sorry about that. Predictive text. Aaggghh.