Hard knock sound, -01 F20C
 

Greetings from Finland, fellow hobbyist!
My first post, but been reading the forum to solve problems since i purchased my s2000 couple years ago.

Few weeks back all of sudden my 2001 s2000 developed a really nasty sounding knock. First i thought it was the timing chain tensioner, i just replaced it with a new original part from Japan; didin't help.
On idle it sounds okay, but starts to knock when opening the throttle valve

https://www.youtube.com/watch?v=hWK8...ature=youtu.be

Any ideas? or should i film a better / longer video?

All great greatly appreciated!

Last time you adjusted the valves? Changed accessory belt and check the pulleys?

Thanks! :)

Thanks for reply!
Never, it had a perfect maintenance record upon buying and has been working great until this point.
By intuition i'd imagine sound like this is coming from slow moving parts, wouldn't imagine valves as the first place to look for?

Longer video, if it helps any. Sound is a lot nastier to bear ears, dosent really translate that well into the video.

Well, if it were me, I'd rule-out valve adjustment and accessory belt/pulley issues, first. Cheap check.

:)

Is it louder from under the car? Get on your belly and listen to the car idle from the bottom. If it is, it could be a sign of rod knock.

I guess it can be started and ran without accessory belt for a while? ill do that tomorrow

Thanks, will check tomorrow.
Im afraid it sounds very much like a rod knock..

If you don't want to take the oil pan off and plastigauge your rod bearings you could send in an oil sample for analysis -> High wear materials means something is shot.

Sounds like rod knock..........does it get louder under load and then almost go away as it spins down? Don't drive the car a lot till you figure it out.

When this happened to me I noticed driving it got louder as I accelerated and soon as I let off gas and left in gear so there was no load or almost engine breaking it went away COMPLETELY. Then soon as you got on it again.....LOUD. That's a spun bearing on your crank.

Other thing to check is your spark plugs. Make sure they are all secure and bottom electrode is intact.