has anyone done a oil pressure test on it, they knock like hell when the top gude of timing chain tensioner wears old, also before doing anything else get someone to check the water pump pulley and the rubber coating is still present and no bits missing and also check the drive belt,, honestly when these break up they sound like the bottom end is going to fall out,, also drop the engine oil leave it to settle over night and pour out the oil without effecting the bottom of catch can and check for shiny particles if crank is nailed it will look like petal black paint, those engine dont tend to do the crankshaft in much unless run low on oil alot or headgasket failures and water in oil will hurt them,