Grinding, " diesel " noise under valve covers

Yessir, I reckon. I mean, I held my hand over the fuel pump, while running, there was a noticeable "hit" felt that was over the engine shaking, but, it was not " In time " with the Constant " sound " like a bad drummer, practice n syncopation.
What does it sound like when completely warmed up at operating temperature? Does the noise subside any?