[tonydb]

hi the cam belt on me laguna 1.8 16v petrol had slip and bent all the valves on the cylinder head, ive stripped everything down an takin the valves out but there are nasty marks on the pistons where the valves have hit it, im wondering if this has caused any damage to the piston, as the cylinder linnings dont look damaged at all and cranking by hand is smooth any help would be great thanks!!

 

[S80]

Hi tony - unless the 'marks' are actually cracks or holes in the piston, I wouldn't worry about them. The valve stems are quite weak on this engine, and they become 'scarificial' to some extent - saving the bottom end from damage.

 

[tonydb]

erm its hard to describe, there not just marks there grovved in the shape of the valves about 1-2mm deep so the pistons have had a gd whack of them, all 16 valves are bent an all the marks are the same on all the pistons, thanks s80 for replying mate

 

[danthevan]

Just check for movement in the pistons too, especially when at the top

 

[Ralph]

Some pistons have indents for the valves from new but I don't know if your engine has.

 

[tonydb]

think there okay, ive just had me mate whos a decent mechanic have a look at them, and he said they will be fine, thank god lol, cheers for the replys boys!!

 

[JQH]

hi the cam belt on me laguna 1.8 16v petrol had slip and bent all the valves on the cylinder head, ive stripped everything down an takin the valves out but there are nasty marks on the pistons where the valves have hit it, im wondering if this has caused any damage to the piston, as the cylinder linnings dont look damaged at all and cranking by hand is smooth any help would be great thanks!!

Hi, not sure if this will help you. I have just dismantled a Kangoo 1.4 because of a big end knock. The cam belt must have snapped at some point, the marks like half moon shapes from the valves punched into the piston crowns. I suspect the valve hitting the pistion caused the bearing on the big end to fail and spin. It may be worth checking your bearings for damage before this happens to you (I didn't know the belt had snapped, funny how the dealer forgot to mention that when he handed over all the documentation and receipts.....beware secondhand dealers in Aylesbury located next to refuse sites)