K-series, keeps eating the cam belt.. Advice please?

Hello all.
I have a strange problem, some might have seen the pictures in the "what have you done to the expensive lander today" thread.

Long story short. In June (I think) I heard a loud bank from the engine, a aux belt pulley had failed, causing the aux belt to lodge on the crank shaft timing belt wheel wich again caused the timing belt to skip a tooth or two = 16 valves hitting things they should not..
Anyway, head was fixed, all new belts, pulleys, waterpump, all new gaskets, the works. I had a mechanic do all this work for me, as life with a 2,5 year old and a very pregnant girlfriend does not give me a lot of spare time, not unless I was to move out that is..

The car worked very well for a week or two, I heard a strange noise from the engine, something was definitively not right. Isolated the noise to the timing belt and found the engine had chewed trough half the belt and destroyed the belt tensioner, no damage to the head luckily.

A new belt and tensioner was ordered, thinking this could be a fabrication fault or something and a new belt and tensioner should fix it. Well it did not work..

The mechanic still says the engine keep "pulling" the belt inwards causing it to slowly grind away. A new crankshaft timing belt wheel has been tried, no change, finally a new waterpump has been fittet, still no luck. The engine keeps pulling the belt slowly inwards.

Anyone have a idea what could cause this? Please don't hesitate to suggest any ideas, no matter how small or insignificant you might think it is.
The car has pretty much been of the road since this summer, I really need it back soon.

My apologies for my poor english, not to confident with technical terms in english..

Some pictures:







Edit: Somhow managed to link to the wrong picture...

The only possible reason is a pulley isn't sitting straight. Would usually be the tensioner or water pump. But it could possibly be a problem with the cam pulleys not sitting squarely on the cams.

Very difficult to tell what's really going on without actually seeing it in person.

I would be checking the mounting surfaces of the cams, making sure there is nothing caught behind where the tensioner sits. If the water pump has been replaced that should eliminate that fron the equation, the only other contact is the crank pulley but I can't see how that could be an issue.

ZDomZ said:

The only possible reason is a pulley isn't sitting straight. Would usually be the tensioner or water pump. But it could possibly be a problem with the cam pulleys not sitting squarely on the cams.

Very difficult to tell what's really going on without actually seeing it in person.

I would be checking the mounting surfaces of the cams, making sure there is nothing caught behind where the tensioner sits. If the water pump has been replaced that should eliminate that fron the equation, the only other contact is the crank pulley but I can't see how that could be an issue.

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Thank you for the quick reply. My thoughts aswell a pulley that does not sit straight, but having replaced the two weeks old waterpump, the two weeks old tensioner (that broke), and the lower crank pulley has also been replaced now, (which I also thought was strange, but replaced it anyway with a new LR part at £150. :S ). The only thing (s) that remains are the cam pulleys I think..

Make sure that there is nothing that stops them sitting flush.

I imagine that when the valves struck the pistons they have bent or made a hairline crack in one of the camshafts, so the cam pulley has a wobble.

Belt alignment is controlled by the bottom pulley. However for the belt to remain on track, the other pulleys need to be on the same axis as the bottom pulley. There is something out of alignment. Was the head skimmed when the valves were done? I've seen a similar problem on a Cosworth BDA years ago. The head had been skimmed off axis, causing the belt to pull in when the engine was running.

A late reply, sorry about that. Thought I would post the solution if anyone in the future should go completely mad and use the search function..

Turned out to be the new water pump. I thought the mechanic that did this job for me had already changed the new water pump, but he had not done that yet. (A bit of language problem)The original one was already binned and the new one I bought seem to have had a fab. fault. After the third one was in place, it all worked well. FYI.

Thanks for letting us know.

great news but I hope you did not pay for the new pump as the one it replaced was faulty.

teddywood1 said:

great news but I hope you did not pay for the new pump as the one it replaced was faulty.

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It was bought from Ebay, probably cost more to return it than the new one that I bought locally.