Hi, what is that knocking sound that occurs when i give it throttle? Sorry I know my valves are noisy. The noise does not go away after it's warmed up. I attached a video of the sound.

 

Got a similar noise coming from my built b16, hoping it is just valve adjustment.. took it to my tuner who reckons it runs too well to be anything serious but I hear a slight ticking/knocking on light load around 3-4k rpm. I assume if it were bearing related it would have spun by now, hopefully someone else can shed some light on this.

 

I suspect that it's piston slap. But mine doesn't go away after it gets fully warmed up which seems to be the case for most ppl with piston slap. Mine is not really audible during idle, and you can really only hear it when you lightly tap on the throttle. As it goes up in rpm, I don't hear it as much as the engine noise seems to drown it out.

 

From what I’ve been told piston slap is usually audible on idle and goes away when you press on the throttle or put load on the engine.. I’m not convince mine isn’t rod knock at this point but I’m waiting for a valve clearance tool and vc gasket so I can do the valve clearances and have a look check over the head internals. I’ve read quite a few threads from similar issues and they mostly spell rod knock.

 

Edit: double post

 

I think I've narrowed it down to being an exhaust leak. I must have a crack somewhere on the stock exhaust manifold or catalytic converter. I only hear it under light throttle, or when i blip the gas. The noise doesn't go away when warmed up and is relatively the same cold vs warm, so it cannot be a piston slap. Its speed/ frequency does not match that of a rod knock. I did a compression test and numbers were 1-4, 195-200-205-210 . I have no oil loss after 1000km and engine doesn't smoke. I think I'm just being paranoid as I just swapped this motor in and it is a 1st gen b16a, head casting date is 90, meaning this engine is OLD. I'm quite pleased with it so far, considering its age and unknown mileage/history.