Timing belt jumped....

[danielgolf]

I changed the timing belt on my 2002 golf gt tdi 150hp engine code arl and I think I incorrectly tensioned the belt...The AA recovered the vehicle to home and I have taken the cam shaft cover off and can see the top of two exhaust valves are damaged.I cant believe what a moron I have been.I had completly misread the procedure for tensioning the belt.I have changed cam belts on my own cars over the years without problems.

A local engineering shop say that generally the damage is limited to the head .So new valves and skimed head are all thats needed in 95% of cases.I cant help thinking that there will be some piston damage con rod etc.Do I look for another engine ?I dont have much faith in "reconditioned " engines though.Any ideas what the parts would be to get it reconditioned .Please help...

[Rustynuts]

Any garage that is prepared to skim the head is well worth steering clear of! The tolerance between head and piston is absolutely vital on a tdi and skimming the head will feck it completely.

The damage caused when a timing belt jumps (or is incorrectly fitted) is sometimes limited to the valves on one or two cylinders, but usually is more like valves bent, cam followers destroyed, camshaft fecked, con rods bent or shortened (due to the impact) piston crowns dented, and even crankshaft bent. This would be a worst case scenario, and obviously a new engine would be a far better option. If you're going to go the journey of the least amount of work possible to get it working, and then sell it, then you might get away with just the valves and cam followers, then trade it in against a new car. The dealership will possibly be more concerned with what they can sell you than what you're trading in.

I've heard of people doing the minimum and then having a valve let go in a few thousand miles. Then you start again.

Personally, I'd be looking for a low mileage pd150 engine to do a swap with, and learn from the error of diy timing belts on pd engines.

[Tobes49]

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Any garage that is prepared to skim the head is well worth steering clear of! The tolerance between head and piston is absolutely vital on a tdi and skimming the head will feck it completely.

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Hold on a second, You can skim a TDI cylinder head, the problem is the amount you can skim it, Most cars come with a 1 notch gasket from the factory this means you can skim .16 of a MM off the head and jump to a 3 notch headgasket this will keep everything correct for a PD engine.

I think the main problem with your engine jumping the cambelt is that the head will be scrap and untill you take the cylinder head off, you wont know how much damage it done

[mulkbear]

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A local engineering shop say that generally the damage is limited to the head .

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IMO it is very unlikely to be just a cylinder head, the piston crown on the PD engines are very brittle compered to some over engines, normally a chipped piston crown is what writes the engine off. I once seen a bent con rod due to a snapped cam belt (roller seized)

If it is just a cylinder head you have been very lucky.

[Rustynuts]

Fair enough, but I've heard of garages skimming tdi heads and merrily bolting everything back together and then have big problems. There was a guy on here last year with that very problem.

I've never heard of anyone skimming one and having success. As you say, the head is generally scrap anyway.

[Tobes49]

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Fair enough, but I've heard of garages skimming tdi heads and merrily bolting everything back together and then have big problems. There was a guy on here last year with that very problem.

I've never heard of anyone skimming one and having success. As you say, the head is generally scrap anyway.

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I've done the headgasket on 3 PD engines now, I know one even covered 100K after the skim and still going strong. You have to know what your doing and the problem is most people dont!