to make the long story short i have just rebuild my cousins qr25de and we had put it in and start it up it ran fine it idles 1500 rpm which is normal for cold start we waited until it lowers to 1200 rpm and i give it a little gas it rev up to 1600 and we just heard a clunk sound like something just hit it and just died, try to start it up again and wont start did compression check and no compression, so i took the engine out and tear it apart again and found that all of the intake valves are bent the exhaust valve are ok but the intake needs to be change, my question is how does that happen the piston looks fine when i put them in the side with the small groove is on the exhaust side and the larger groove is on the intake side im not sure if i mess up something here, and on the timing chain i did just exactly what JWT did and i fire up fine until i give it a little gas and it bent the valves. can any one give me some hint, did i put the piston in wrong or did the timing wrong or do i need to let it idle longer before giving it gas.

any help thanks...

Tough to tell exactly, but it sounds like the timing was off.

find out it was just timing it was fix and it ran fine now