Ford Repair: 97 Mountaineer 302 Engine Knock, roller lifters, spark plug wire

Question
I have a 97 Mountaineer with a 5.0/302 Engine. This engine has roller lifters. For the last about 25K miles, there has been a "ticking/clicking" noise from the engine which is most noticeable at about 1800 rpm. Good oil pressure, runs great. If it were a bearing it would've conked out by now. I asked everyone I know including taking it to the dealer for diagnosis. The unanamous opinion was that one of the lifters was clicking. SO...I tore the engine apart and put in 16 brand new Ford lifters. Started the engine and the same clicking! I checked the exhaust manifolds for cracks, put in a new cam synchronizer. Got a stethascope and the noise is most noticeable around the bottom front of the engine. Timing chain? Oil pump shaft? HELP!

Answer
This is not a common problem that I see at the Dealer.  Without hearing and trying to pinpoint the noise, I can only guess where it might be coming from.  I would come to the same conclusion that you have, the timing chain and oil pump are on the lower-front of the engine.  The oil pump is driven from the camshaft, so it spins at half of the speed of engine RPM; keeping this in mind might help to narrow it down.  If it is rhythmic and not random, it would have to be a rotating part.  It may be a wrist-pin or piston ring.  Try removing the spark plug wire or fuel injector connector to one cylinder at a time.  The lack of combustion may cause the noise to change or stop.  This may help pinpoint the noise to a specific cylinder.  There could also be excessive thrust in the cam or crank.

I hope this helps,
Dave