ok i did a video with sound using my phone... i can hear it when you listen near the front tire and on top of the engine. i dont know if this is normal or loud enough but check it out and let me know what you think.
its only 38 seconds and its dark in my garage but what i did was put the phone near the front tire then moved the phone to the engine.
Nismo :: Nismo knocking video by ryanboy20 - Photobucket