Engine Making a TERRIBLE noise

[kustom]

HELP! My car was running fine, until I finished changing the oil and putting in new spark plugs. Now the top of the motor is making a TERRIBLE clattering noise. I took the spark plugs out, and spun the engine over, and everything sounds fine. I Re-installed the plugs and wires, and the clattering continues. I re-drained the oil, and made sure there was 4.5 litres of new oil back into it (Rotella T 15W40), and spark plugs were properly tightened (NGK BP5ES). Still loudly clattering!!!???!!!

Any ideas?

[So Cal Mark]

sounds like something fell in one of the spark plug holes. I'd remove the plugs and look down each cylinder with a small inspection light. Look for clues such as a damaged spark plug or fresh nicks in the top of the piston

[majicwrench]

Mark may be on the right track. A little pen lite, pull plugs roll each piston up and take a look at it. if something is rattling around in there will likely leave ding marks on top of piston. And take a good look at each plug to make sure nothing is hitting.
If something in there, then ground coil wire, pull plugs, take shop vac, and stick over plug hole try to get a decent seal, now have someone spin motor over, you grounded coil wire right?? Praying/cussing often helps here too. I have sucked things out of cylinders many times over the years, but sometimes it gets wedged and will not budge.
Got to metion, are you sure plug wires on right??
Good luck,
Keith

[kustom]

So... I spent the weekend trying to diagnose this sound. My garage looked like an operating theater with multiple guys listening to the motor with a stethoscope. After we discussed the possibilities (wrist pin, rod bearing, debris in cylinder), the consensus was that we were stumped . I poured in a bottle of GM EOS (Engine Oil Supplement). Within 5 minutes the noise was almost gone . Now it just sounds like some valve clatter at 3000+ rpm. I might try some Lucas after I drive it for a while to see if it improves. Unfortunately I can't drive it until my panhard rod arrives from Vick's. Last week, it broke at the apex of a spirited corner (what a ride that was...but that's another story).

[pope]

Make sure you have the right gap between the tappet shims and cam lobe. sounds like your cams are slapping the cups.

[So Cal Mark]

my bet is that the EOS has nothing to do with less noise, but that the item is getting pounded into the top of the piston so it doesn't hit the cyl head/valves as hard