D5 (D5244T to 2005) Snapped Cam-belt Question

[jp11]

Originally Posted by stutgart69

Attachment 65454 The offending knackered tensioner. (I put the belt back on for the sake of illustration)

Attachment 65455 The results;

Attachment 65456

Oohh, that makes me sick to my stomach, hairs standing on the back of my neck

[Thehood]

Crap engineering no wonder the likes of jagusr nissan bmw merc mazda honda use chain drive

[stutgart69]

The belt is still in one piece.Indeed these seem to be remarkably tough and resilient items that rarely break. The tensioner on the other hand looks like a cheap, nasty piece of sh**!

[stutgart69]

Okay. I have a question for the experts.
With the belt back on,and correctly aligned, (albeit it is running on a knackered tensioner) I can manually turn the engine all the way round. It feels a little bit sticky in places but it still turns.
Question is, would I be able to do this if a valve was bent? (even if it was just slightly bent) . Or would it be impossible?

[Mark S60D5]

Sounds promising although the only definate answer would be to fit a new tensioner. The stickiness you say that you can feel is probably the compression stroke on each cylinder, again if its at a regular interval and duration then this would be good as it means each cylinder has the same ( roughly ) compression.A bent valve would allow compression past. Bite the bullet and put a new tensioner on, fingers crossed you'll be lucky.

[stutgart69]

Thanks Mark

[Clan]

The way that belt cut its way through the cover means there was some kind of early warning it was happening , unusual noises and smells from the engine bay ... i would say that took some miles to do that damage before it finaly gave up .. It will most likely need another cylinder head to repair ... the bottom end is very robust so likely to be ok .

[stutgart69]

Admittedly Clan, there was a strange noise coming from engine every once in a while, but I couldn't figure out what it was. Rather embarrassingly,stupid old me thought that the Auxiliary belt was in fact the timing belt, and I checked it and thought "Yeah that all looks ok".
However, no noises or smell just before it broke down that I could tell, and there was 3 off us in the car at the time.

[wrinkles]

I had it happen to me some years ago on a 740 I put a new belt on crossed everything and started her up , perfect no damage and it went on for many thousands of miles , perhaps I was just lucky.

[stutgart69]

I don't know whether to be hopeful or fearful to be honest mate.
On the one hand it seems quite encouraging to me that I can turn the engine round without the pistons hitting off any valves, this imply s to me that the valves cant be bent. Surely if a valve was bent it wouldn't seat right in the head and therefore the piston would come up and hit it?
On the other hand, when someone with Clans experience is doubtful, then it doesn't bode well.