My thought is rod knock. See if you can put your ear close to the intake runners and see if one runner is louder than another or if its front or rear of the engine.

If you are AP1 and early '02 or older and didn't upgrade your banjo bolts likely you spun a bearing!

I did that with my car and if it sounds very metallic like a screwdriver hitting metal and it doesn't go away at any RPM, gets louder on accel and almost goes away when decelerating(engine braking) then it's def spun bearing IMO. When you decel it takes the load off the bearing and the knock virtually disappears! Under load it gets louder.

 

Thanks for the input. Spun bearing was actually my first thought as well.

I have 2000 AP1. I put a whole another quart of oil in my engine today and it is barely at the low mark

 

What's this up grade your talking about never hurd of it and I have a early 02 my self

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Just do some hunting on Banjo Bolts S2000. You can even find the ENGINE NUMBER(not vin number) that will give you an idea if yours was made after they changed the bolts. They are tied into the oil sprayers.(more oil flow) I found the engine number on my replacement '02 engine and found I was about 700 engines after the earliest switch over number found. Billman250 is a screen name to search on this too as he posted in a thread on this topic.

https://www.s2ki.com/s2000/topic/884...-oil-sprayers/

 

Bump

Anyone have any idea what the noise is? My best guess is rod knock.

I'm undecided if I want to rebuild my current engine with a few new pieces or if I should just buy a used block and build that one. Anyone have any input or experiences with either of those?