billygsr99

car 99 gsr with about 10k miles on the motor after rebuild recently engine started knocking while driving on the highway i made it home keeping revs low. start the engine and no knock on idle or low rpm, but as soon as i give it some gas to about 3k rmp it starts knocking rappidly on and off. it doesnt look that its coming from the bottom, and i found a vid on utube that sounds similar after about 1min through the video?

http://www.youtube.com/watch?v=O4nx1...rom=PL&index=3

billygsr99

any1 knows what could b the problem?

LoveDatVtecDC4

If it's knocking then you know the motor is hurt, no matter what else. It could be anything, from a dropped valve, to a spun bearing, to rod knock. The only way your gonna know is when you rip it apart or do a compression/leakdown test.

PROJECT TEG

mhy brothers b20 had a sound that sounded kinda like a ticking or a exuast leak we pulled the valve cover and his valve lash was loose as hell maybe ur valve lash is screwed up just a thought cause u said it didnt sound like it was coming from the bottom end pull the valve cover and check it over before u start freaking out its worth taking a look at hopr that helps

billygsr99

its kinda obvious, would never thought of that untill you told me, ty but u not being helpful

the first thing i thought is the valve clearance, so went and readjusted it but noise is still there. good thought about the lash but it can't be bcause after adjusting the valves i went through every lash 3times to tighten each of them

billygsr99

when the valve drops, does the motor still run or the valve gets stuck in the chamber and motor dies? also, could it be timing belt skipped a tooth? so timings is off and piston is slapping the valve?

92civic_hatch

it sounds like part of your piston skirt is cracked or cracked off. this would explain why you dont hear it at lower rpms. after about a minute in that video, that doesnt sound like just valves.
your valve is not slapping off the piston

billygsr99

near heard that b4, but u never know. but on low rpm there is no knocking what so ever... also compression is good