90 awd tsi pistons have rings in the four sides

[ohionl22]

Hello and how is everyone. I picked up a 90 tsi and it had a broken timing belt i fixed the timeing belt without taking the head off and it ran fine for about 2 days, finally i tore it apart and one row on the head, the back row is all burned, i have 8 bad valves all on one side, and i bent valve on the other side. Now the pistons on the top are groved from where the valves hit the pistons. A friend said to just file it down, but how do i know if i can. Im kinda new so i figured i would ask. How hard is it to take out the pistons and put new ones in. I looked at the manual and you have to pull the motor. Is there any other way. There are alot of good links on here so if someone can point me in the right direction it would be great. Thanks
nick

 

[mobythevan]

If you polish the tops of the pistons so you can tell they are not cracked, then you can just smooth out any areas that the valves hit. The idea is not to have any sharp edges or small protrusions on top of the piston because it will lead to more pre-detonation because it gives a place for a hot spot to start. My valves hit the pistons and the pistons are ok. Also there are normally four valve reliefs in the top of the piston to start with, so look closely and see if the valves really hit and if it just needs to be cleaned up.

 

[wolf20043]

And actually, with the head off, all you have to do now is pull the bolts where the downpipe bolts to the 02 housing, pull your t-case and drop the oil pan, and you can remove the pistons that way with the motor in the car still.
Mike