I've taken the head off my mates 2wd saff to change the head gasket and when I lifted it off all four pistons have damage from were the valves have come in contact with them at some point in the past probally from a timing belt failure.
He has only just bought the car and the head gasket and timing belt look fairly new, but he wanted to upgrade to a group A head gasket. The valves themselves look fine. My question is it ok to run the engine with this clipping damage?

 

common problem on cossies slight marks not a problem at all, if car was running well before just refit it.

 

While the head is off, it would be mental not to at least check the valves.
Marks on pistons will be ok as they are a lot stronger than the valves.
I would be concerend if all four are marked though, has the head been skimmed a silly amount ?
My car was running perfect, but had 16 knackered guides, and eight leaky exhaust valves, as well as knackered dizzy.
tabetha

 

What height should the head be?

 

I have seen it somwhere but can't readily find it, will have another look tommorow
tabetha

 

139mm std
138.68 mm fords lower limit...

all of the 2wd ones i've done has all had inlet valve marks on the pistons

This is because some MUPPET times them up using v on the crank as TDC

It will be fine If it was running ok before

 

FORDS lower limit is pathetic, it is perfectly useable way below this limit, just ford won't get a new head sale out of it!!
12 thou and then no good, what a laugh, what a load of crap.
It is up to you wether you take the opportunity to check the valves/guides or not, as they are VERY prone to wear, as it will not be me doing the work or having the additional expense/hassle, persoanlly I don't care, as they say you can lead a horse to water but can't make it drink, if you want to chance it go ahead.
tabetha

 

I fully intend to check all the valves and guides, the tappets and stem seals are being replaced anyway.

 

over haul the head while its off...