Timing Belt Problem 2006 Aveo ls

2006 Aveo LS that i just bough
Started car up was taking off and thump and car quit.

Would not start well i knew what had happen so i
remove top timing cover belt is still in place so i go
on to removing bottom cover..

Some +++ had replaced the belt and not the idler
and it had froze up and belt slipped off, Removed
valve cover and was able to put a screw driver
between cam and lifter so i now have bent valves..
Head not removed at this point.

My question here is after looking a some u tube videos
i saw photos of valves putting notches in the pistons
if this happen do i have to replace them also?

I just dealt with this, so hopefully I can offer a bit of help.

Just bought a 04 LS sedan for my son's first car - got it for $500, knowing the timing belt had gone out. Pulled the head, and scored 16 for 16 on bent valves - in fact, the face of all the valves was flush with the head surface.

The pistons do have a small relief notch in them from the factory, so you may be seeing that in some of the videos as well. A lot of it can depend on the conditions when it goes - a manual trans at highway speed is more likely to be catastrophic than an automatic just starting to rev up.

I found one small nick in the #3 piston, that I was able to dress up with a jeweler's file - you want to make sure there are no sharp edges, and no major dings right at the outer edge of the piston circumference (above the ring grooves); as these will cause hot spots and premature piston failure.

I replaced the following:
- all 8 intake valves
- all 8 exhaust valves
- all 16 valve guides
- head bolts
- associated gaskets
- tuneup bits

when it was all said and done, car fired up instantly; all total, I probably have about 10 hours in it, including rebuilding the head and lapping the valves in.

Thanks for your detailed reply, jimzdat. And welcome to the forum!