wierd knock( a 4 cyl)

[SnakeEyeSS]

FRIENDS car has a loud knock coming from under the valve cover, its a 4 cyl, and it gets louder the higer the throttle.

is it the knock sensor?

 

bent valve?

 

bad timing?

 

these are my ideas. can you guys help quick?

[CMNTMXR81]

A knock sensor does nothing but detect knock.  It doesn't move.

 

Sounds to me like their is slack in the valvetrain.  When was the last time he had the rocker arms adjusted?  If he's had them adjusted recently (and they were done correctly) perhaps a lifter (or a few) are going bad.

[SnakeEyeSS]

guys at chevy-talk are betting its a bad timing chain, they guys is getting the engine removed and partially torn down saturday(FOR FREE!!!, GO FIGURE!!! he knows a guy), I'll find out what it is then

[CMNTMXR81]

Could be, but if the chain had jumped, his engine wouldn't run very well and if it jumped enough (back or ahead), he would've also put a valve through the top of a piston quite possibly.

[SnakeEyeSS]

he had it checked out, verdict is: bent rod, he's getting a new engine.

[CMNTMXR81]

That would definetely cause some knock.