tin1man

2001 f-150 4X4 Started knocking while driving going down hill, no knock going up hill. Steadily got to the point of knocking pretty bad standing still. Doesn't sound like a bearing but have removed torque converter and it still knocks so its not loose or broken flex plate. It is in the lower rear of the engine, no pieces, filings or parts in the oil pan. If you have ever heard a broken flex plate it has the same kind of sound. haven't got to the point of pulling pistons but the sound doesn't change when dropping cylinders. So sound familiar to anyone??

torkum

Probably a rod knocking. Ford has used the snap rod design on the Triton [Modular] motors. The problem with snap rods is they are made as one piece then scored for the cap and snapped. This makes for a irregular wear on the rod around the crank and causing the rod to "egg". Its also why the rods and caps can not be switched when reusing the rods after disassembling.

tin1man

But if it was a rod bearing couldn't you tell when you killed that cylinder when running?

torkum

Think about it, when you "kill a cylinder" all you are doing is stopping the ignition process. The rod is still attached to the rotating crank.

tin1man

Usually with a lot less pressure though.

Beast7.3

If I understand Torkum right, it's not about the pressure created in the chamber that's making the pop, its by the abnormal shape of the rod that causes the knock. So pressure doesn't matter.

torkum

Its like a egg shape rotating inside a perfect circle.

tin1man

Doesn't seem to be one of their better Ideas does it? At any rate the caps are the next thing to come off. Let you know what I find.

tin1man

Before I drop the pan I want to check oil pressure with manual gauge, is there a preferred location to hookup a gauge?? I'm thinking my dash gauge is not right.

torkum

Pull the oil pressure sensor and hook it up there. This will produce a code by disconnecting it, just erase it when you are done.