one piston clean, others not and head gasket gone

[rocky_dude23]

right well im taking my engine apart because the head gasket is gone, but there is one thing im not sure about,

one of the pistons is clean and has little almost scratch like marks on piston and on engine head, this is probably what caused the head gasket to go coz one of the lil scratches/dents has caught abit of the head, i think thts where the coolant leak is,

but what im thinking is either its clean because someone has had piston replaced thats why its clean, and also i think maybe when they did that something got into where piston is and thats whats caused the lil dents/scratches which in turn has made the head gasket go and created that creamy stuff in oil etc etc

or because the head gasket is gone and water/coolant is getting into combustion chamber, because of the lil explosions it has evaporated the water obviously and done an almost steam clean to the piston

but one thing i know is for sure something has gone in and created that those marks how i don't know and wheither they made the head gasket go, again i don't know i just need someone's opinion

(just thought id note as well the other pistons are dirty and black because of carbon build up, before hand coolant was going down alot when accelerated adn white smoke came out back due to water vapour, and engine head is needing to be skimmed because on the far left of it ( as though your lookin at engine from front of car) the head is not dead flat on that bit compared to other end

[cazzz1975]

do the marks look like bits of piston ring?, I would be looking at whether a bit of the piston ring has broken off and been stuck between the head and the piston

[TWR]

Check the cleanliness of the joint between the head & block, also the sump, you can normally tell if the gasket has been replaced by overspill of gasket sealant, was the car / van burning fuel in the offending port? If a petrol when you removed the plugs was there an indication that one Cyl was getting more fuel that the other three? the plugs will indicate this by their colour, Or similar the injector, where they spraying the fuel well? when you stripped the head did the thermostat show signs of new to the age of the car? there are many other things that can cause water into the bore, as said Gasket, The bore liner cracked, an injector sleeve cracked. all pistons should be individually numbered, check the nos.

[chas2008]

how long have you had the vehicle ?
just a quick look at your post indicates to me someone has been there already, maybe not done a very good job or just enough to keep it going to sell it..
Dents in the piston crown could mean its dropped a valve at some stage and if the piston is that clean not long ago..