Every since the heads/cam install I have had a slight intermittant tap in the motor that I just chalked up to a fussy lifter. Well last night I was on my way to the track and romped on it to check out the a/f of the tune I just loaded on it. The a/f was a little too lean at 13.4 so I got out of it pretty quick. After letting out of it I heard the loudest tap I have heard yet so I pulled over. When I pulled into the gas station, the guy I was following had this imediate 'WTF" look on his face as he could hear it as I pulled up. I popped the hood and it sounded like someone had a small hammer and was tapping on the valve covers in the #5-#7 cylinder area. I pulled the dipstick to see if I had oil and discovered it at the full mark but there was some metal powder in the stick. I wiped it off, stuck it back in and pulled it out with even more metal residue on it. So I am really worried at this point. I decide to ease it back to the house tapping the whole way there untill I get into my neighborhood then it stops. I pull in my driveway, pop the hood and low and behold.. quite as could be. All I heard was the normal sewing maching sound of the drive train. Anyone have any ideas?? I am leaning towards a lifter but that dosnt explain the metal in the oil. Help!!

 

I would think it is a bearing. You have a good bit of miles on it if i'm not mistaking and they are all hard miles no doubt. Did you notice a difference in your oil pressure? This same exact thing happened to one of my buddies and he changed his oil the next day and it was full of tiny shavings. He's a GM mechanic and has no idea so he's doing a swap to the 6.0. I'd start looking for a 6.0.

 

Eating a bearing,maybe...but why would it get quiet...some kind of debris drop down into the engine when you were doing the work,got pulverized,dropped into the pan? Good luck!

 

It is definately topend/valvetrain. Usually a bottom end knock will go away at idle and get louder with rpm. This is not the case. Once it starts tapping it will do it at idle as well. Oil pressure is good.. 40#@idle, ~50# crusing and will jump to nearly 60# at wot.

 

bigkid mine is doing the same thing only now it is a constant tick..
before I did the spring upgrade, it would start off soft and then get loud as hell. now it just ticks every so often. specially after I romp on it..
I went ahead and bought a new set of lifters, and will be replacing them here shortly..
let me know if you find something else out????

 

Not surewhat the problem is, but good luck and change that oil.

 

damn kenny you can't catch any breaks here lately can you.

 

Mine's making a similar noise, but I thought the motor was just noisier b/c it's aluminum. Hmm.....

 

13.4 A/F shavings=bearing (most of the time) If it is tapping though, I think you are right about being topside. Broken piston??? That noise wouldn't just go away though...
Man I hope things turn around for you soon.

 

my truck did the same kinda stuff. and i dont really want to say what really happened.
but, if i were you, id start puttin some doe back tward a new motor. check compression!