Afternoon,

Have just removed the head of my saff to replace head gasket.

When i removed the head, i found some marks on the pistons from the valves, the indents are about 15mm in length and about 1-2mm in depth, on the inlet side.

I assume this is from inaccurate timing!

The valves dont appear to be bent, as theyre is equal gap around the valve seat to the head.

are these marks going to cause any problems?

Cheers.

 

Marks will not cause any problems, and not at all unusual even when timming always correct!!
Nothing to worry about.
tabetha

 

Thats excellent news, thanks for that!

I am surprised that they can collide even when timed correctly, is that what is meant by piston slap?

Cheers.

 

NO, piston slap is just that the piston tries to twist in the bore and you get it rocking in the bore as the piston passes tdc each time, as they heat up it stops as they expand slightly, the 4wd pistons had a slightly different wrist pin/gudgeon pin offset to counter this, but piston slpa is not harmful in anyway, just annoying!!
The marks on the std cams/pistons can be from a heavily skimmed head or overreving(chipped) and are affectionately known as KISSING marks, but even some unskimmed heads/engines do this, it is so slight though, the crowns(tops) of the pistons are VERY thick so don't present a problem.
tabetha