peeair Posted October 2, 2012 Share Posted October 2, 2012 Does anyone know if the valves will hit the pistons when the cambelt fails on the Ducato 2.8 engine,the belt tensioner retaining bolt failed on mine which caused the belt to come off, fortunately it's covered under warrantybut i would just like to know how much damage it could have caused. Thanks. Link to comment Share on other sites More sharing options...
BGD Posted October 2, 2012 Share Posted October 2, 2012 On any engine I think the the answer is a big yes. If any cylinder is doing its "suck squeeze bang blow" four-stroke cycle, but the camshaft is either not turning, or is turning out of synch with the crankshaft, then valve(s) are still being held open at the top of a cylinder by the cams on the camshaft when the piston on that cylinder is pushed up to the top of that cylinder by the crankshaft. Crunch-time as they are then forced together hard. Big damage to the valves and possibly to the pistons and other parts too is I think inevitable. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted October 3, 2012 Share Posted October 3, 2012 peeair If the motor fitted to your Ducato is 'non-interference' type (ie. if the cambelt breaks the valves and pistons should not contact each other) there should be no damage. If it's 'interference' type, then it should be anticipated that a cambelt breakage will result in damage. This wikipedia entry http://en.wikipedia.org/wiki/Interference_engine advises that "virtually all diesel egines" are interference type, which was my own understanding. It's really pot-luck as to how much damage may result when the cambelt of an interference engine fails. You might get away with just a few valve's being bent (as was the case with my neighbour's petrol-engined Vauxhall) or the complete cylinder-head may be a write-off (as happened with my sister-in-law's diesel-engined Ford). The faster the motor is turning when the belt fails, the potentially greater the damage, but the only sure way of finding out is by dismantling the motor's top-end and inspection. You might want to copy your inquiry to the "Motorhome Matters" section, as Nick Fisher (euroserv) should be able to provide expert advice on this. Nick is the forum's Fiat Ducato guru, but I note that he has never posted to "Hints and Tips". Link to comment Share on other sites More sharing options...
stantheman Posted October 6, 2012 Share Posted October 6, 2012 As Derek says, it does not follow that, in the event of a cam belt failure, the valves will 'collide' with the pistons. However, even if they do, the engine is not necessarily a write-off. It happened to me with a Fiat saloon car. It took me a bit of muscle to get the bent valve out and I'm not sure that it didn't distort the cylinder head, but the fact remains that it doesn't always spell disaster. Link to comment Share on other sites More sharing options...
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