posting for a friend:help diagnose knocking sound

[GTRU]

I'm just posting this for a friend to help him diagnose his mystery knocking sound.

I quote him:

"So I'll try to make this as short as possible. When my engine is running there is a knocking sounds coming from the engine (I think the back, 6th cylinder area). It's really noticeable when the engine is cold and seems to get a BIT better when its warm. Also, it's alot more defined at lower rpm and harder to hear at higher rpm and the knocking follows the rpm's. So basically I figured piston slap, rod knock, etc. So I started by taking the head off to find nothing wrong with the head except for the #6 spark plug was extremely crooked by previous owner (almost 45 degree angle!) and was barely showing on the inside of the head (figured it was either not getting a spark at all or just a faint spark). Also, the top of the bottem end was in perfect shape, no scuffs or detonation. So now I took the bottom end out to check underneath and to my surprise, the bottom end is perfectly fine. No shot bearings, lose crank, nothing. So I'm extememly confused as to what this knocking sound is and where it's coming from? Has anyone on here experienced the same or similar problem? ANY help would be great! "

I heard the motor run myself, when you initially blipped the throttle the knock would be at its loudest but then level itself off and quiet down somewhat.I took the engine appart and found nothing abnormal other than the crooked spark plug.I know cyl number 6 wouldnt get proper spark because of it but I don't see why that would cause a knock.I didn't have the chance to take the rod and girdle appart to check the bearings yet but there was nothing wrong from what I saw.All rods has the same slight side to side movement on the big ends.

[MIKEGTR]

I think your friend already posted

[GTRU]

Cheers Mike, I was unaware