we use a normal stethescope all of the time to check for noises...

if you had cams, i would possibly blame that....

i wonder if they primed your motor properly when they started it, to get oil up into the valvetrain...

change to another oil, and let meknow what happens

cb

 

Bent valves ?

 

Thought about it... Hope not.

The only thing i can think of is....

When the bearing spun, and over lapped each other. That piston raised and hit a valve. but really don't think thats the problem.