Ok, well ill give you a few things that can cause a knocking sound like you described and are relatively easy to check, and probably save you the trouble of the new engine.
I would eliminate the valves clicking because sounds like you got sufficent oil.
A torque convertor that is loose on the flex plate or a cracked flex plate will cause a knockiing sound like that, usually mistaken for a main bearing going. Its normally most noticable in idle when speed is low and no engine load.
Next thign to do is ground out one cylinder at a time and see if the noise stops. Do this by putting a piece of vaccum hose in the spark plug wire and on the spark plug then grounding it out with a grounded test light, if noise stops when one cylinder is disabled it could be a piston pin that knocks, it also usually gives off a double knock sound.
I would eliminate timing chain noise as if the vehicles chain is worn that badly your vehicle will be running poorly. With main and rod bearing noise it depends on speed and engien load the noise it will make so I dont think that would be the problem.
If you have a heat riser remove the vaccum line from it and remove the drive belt, does noise stop when this is done?
Thursday, July 31st, 2008 AT 4:37 PM