I heard the most god awful sound come from my engine when I had the clutch pressed in and reved it... A bit high 5-6k listening to my new exhaust. At first I thought. "Damn... I just threw a valve... but then I noticed when it went to idle... it was smooth and the sound was faint." I know I did the wrong thing but I opened the hood while it was running and I listened to see what it was. I head a tick from the flywheel I think.. Also shards of metal were all over the back of the engine. This is the only conclusion I could come to because I can still move the car and the Idle is perfect with no missing.... If it is missing I cant tell but any help would be appreciated. Thanks alot