[Sunny the Model A]

if it is knocking after warming up but it doesn't knock when cold, it might be excessive rod to crank clearance being cushioned by thickened oil. once the oil warms up, my guess is that the oil flows faster and the pressure drops causing the knock. Is my theory correct? I have heard of this with diesels but it might apply to model a engines as well due to the low oil pressure of these engines.