Originally Posted by clm2112

Ok, since the tapping noise goes away after a few minutes of run time, I would cross bad lifters off the list. If a lifter was really done, it would tap most to all of the time.

Heres the short list of things that go wrong on a lifter: 1.) Sludge buildup inside the lifter body/plugged orifice keeping oil from filling up the lifter. 2.) Busted spring inside lifter body. 3.) Lifter bore oversize/worn. 4.) contact surface with cam damaged/wrong cam and lifter types.

1 and 3 are pretty common in high milage motors. #2 is often assembly screwup or over-reving the motor..not enough lash on the valves, way too much lash on the valves, bent push-rod, not enough clearance in the valve springs. #4 is just plain stupid s*&% (Like using a flat tappet lifter on a roller cam or vise-versa.)

So, in sum, you don't really have a problem with the lifters themselves (or at least it's unlikely you have a problem with the lifters.) The symptoms are more like a weak oiling system or excessive wear that's keeping the oil pressure from comming up fast.

If you want to hear for yourself what a bad lifter sounds like, warm the motor up, take off a valve cover, then with the motor running, loosen one of the rockers till it rattles then tighten it back up again. This gets a little messy, but it's the old school way of setting the lash on solid lifter valve train. (NOTE: This is just for the purposes of demonstrating the sound of a bad lifter, this is NOT the correct procedure for setting the lash on a HYDRAULIC lifter.)