ok heres the problem my car started making a loud clanking noise. so i thought it was rod bearing. i replaced rod bears, oil pump water pump timing belt. and checked the main cap bears those were ok. put everything back together. started it up still clanking. did a compression test. from timing belt side it went 155,152,151,80 so i started to pull the head but want to know would it be a valve bent problem or a piston problem?
thanks

 

A leakdown test will answer your question.

 

i just pulled piston 4 cause thats were the noise sound like it was coming from and the noise sound is coming from the trans when i rotate the crank by hand