cambelt tensioner broken

[ollli]

hi all

just done a total engine revision got it back together no problems run for 6days and then yesterday the alternator went and today the cambelt tensioner mounting bolt broke off in the head damaging the hydraulic tensioner aswell my question is has this happened to anyone else and can you be lucky and have no damage to the valves or do you hit the valves no matter what,i got no warning and it was at very low engine revs.

oli

[ollli]

well the answer is yep bent the lot gonna strip it this week and check the valve guides

[Crasher]

This is becoming a common problem, it happened to us on a BKD 2L 16 PD TDI engine in a Golf 5 about a month after the belt was done. Now we replace the stud if we suspect the cam belt has been done before because we suspect people over torque the tensioner. The tightening torque for the nut on the stud is quite critical, what did you do it to?

[ollli]

20nm + 45 degree but if gave it a healthy nip and i think it must have bin too much , another therory was that some things picked up and given the belt a shock and if the belt was too tight that i could find the weakest point this time the mounting bolt

This is becoming a common problem, it happened to us on a BKD 2L 16 PD TDI engine in a Golf 5 about a month after the belt was done. Now we replace the stud if we suspect the cam belt has been done before because we suspect people over torque the tensioner. The tightening torque for the nut on the stud is quite critical, what did you do it to?

[ollli]

7 bent valves ,all the hydraulic tappetts cracked and a valve trapped in the head of which i'll have to chop out i also think there will be some damage to some of the valve guides so i've a bit to do

[Crasher]

No, just a weak stud design. When they were M10 in the old days they never snapped but some idiot decided to make it M8!