HastedS2K

So i took a video after i read your reply.. From cold start i didn't hear any knock and after 3 mins being idle knocking noise starts to make noise so i started making this video. And so you guys know you will notice from minutes 1:43 to 2:40 knocking noise is fading and by 2:40 to 3:00 minutes its completely gone. Weird?!

Video with revving

MM3Kwolik

If it goes away completely once warmed up fully you can pretty much eliminate any sort of bearing issue. This COULD be considered piston slap, but I'm not sure, because I've never heard it on an S2000 before. If it were bearings though, the sound wouldn't go away and would get far worse once warmed up.

HastedS2K

Oh ok thank's for your response. I've just searched piston slap and i see its common on GM engines, correct me if im wrong.. Anyway, so do you guys think this knocking noise is harmful to the engine? I dont DD my car, i only use it on weekends and not driving it more than 10 miles. What do you guys think/advice?, should i still drive the car or not and bring it to a mechanic right away? I still drive it though. 2 weekends i think.

BTW this happened after we SEAFOAM & VALVE ADJUST.

MM3Kwolik

PM Billman250 and ask his opinion (refer him to this thread). Chances are he has heard this before and can confirm my suspicions or tell you what he thinks.

HastedS2K

Alright thank's a lot!

wpn52k

sounds like a spun bearing to me sorry. drop the oil pan and the cover and see if theres any movement in the conrods or if its darker than the rest. it doesnt sound too bad so you could probably get away with just a crank grind, new bearings and conrod.

s2000maniac

My AP1 makes the same noise. Once its warmed up it goes away. Thats pretty much normal.

Kami Speed

Im with the guys, sounds like a spun bearing.
Good luck friend.

-Adam

s2000maniac

well i dont know about you guys, but my AP1 has done it sine i bought it and that was 35,000 miles ago. If it was a spun bearing i think it would have showed up by now, not to mention two oil lab analysis says my engine is running pretty healthy. If it was a spun bearing I think it make the same noise even with a warm engine..

HastedS2K

Ok so if you have a spun bearing will the car run funny or slower something like that? I never felt any difference ever since though.