On saturday after work i started my car up and heard what sounded like a horribly loud rod knocking. I have dropped my fair share of engines in my day doing dumb things so im very careful. Soon as i heard it i turned the car back off checked the oil. No shavings oil levels fine and oil looked clean. So i turn car back on and the noise is gone. Anyone have any ideas as to what this could have been. I mean it didnt pop a engine light or anything. Should i be worried i have only drove the car a few miles since it happened and it is not making the noise at all car is running perfect. Temp is good all fluid levels good no leaks cracks smoke or anything.

Did you fix that exhaust shield on it? Because it does make a rapping noise that sounds like knocking.

You should be concerned. Loud heavy knocks are usually bad news. The harmonic balancer (crankshaft pulley) will make a really loud knock when it goes bad. Can be erratic too.

Wasnt heat shield. It was noise definately coming from top of engine. I thought something in supercharger when i heard it. If it is only doing it sparatically how do i check to see what is wrong. Cause car is acting perfectly fine now.

Maybe the coupler. Let'* see if some supercharger guys can help out.

Never heard a SC coupler that could be described as horrible knocking, nor one that comes and goes, but let'* look into this anyway. Remove the SC belt and spin the SC forwards and backwards. Any slop? Any pulley movement in either direction without resistance?

Let'* take it farther. Look at the front face of your harmonic balancer/crank pulley. You may have to look from underneath or with a flashlight and mirror. Is the rubber face of the pulley torn around the outer edge near the belt paths?

Well i feel a little bit stupid but im very thankful. Since its been dark every time i have been near the car since it happened. This morning i was running little bit late to work and figured i would check under hood to see if i could get any more info about the car. And to my wonder i find a piece of my belt that attaches to the alternator tore a strip about 1/8" off all the way around belt. It was smacking something causing the noise. I feel relieved that it was nothing more major but dumb cause i didnt notice it before. It must have been tore just a little bit so when it was rotating i was noticing the tear go around (and it was dark). Problem solved thanks everyone for the input. That belt looks like a devil to change. Guess ill have to check it out tomorrow on my day off.

Wow! You really lucked out. Glad you found it, and thanks for letting us know what it was!

Which belt? That'* usually caused by a bad tensioner or idler pulley.

I actually found the belts were easy to change on a Series 1 supercharged bonne. Shouldnt be too hard for ya. Just remember the routing of it. If you dont have a picture of the belt routing then draw one out before you take it off.

Erik