Alright, so I pulled the "bad" engine from the 2g this weekend, and took it apart to check out what is wrong with it (have a spare ready to go in). Turns out the whole damn thing was recently rebuilt. Absolutely no wear on the rod bearings, and mains. Turned the cams on the head and no signs of bent valves, all seem to seat correctly. The reason I got a new one was because of a really loud knocking, I took the VC off and cranked on it and could hear it on the second piston, when the intake valves went down. There are no signs of any nicks on the piston. Rings look new, crosshatch can be seen in the cylinder walls. There is a little wear on the sides of piston 2 and 3, but nothing that catches your fingernail when running against it. WTF could it be, and what else could I check?

I guess the first question would be...are you sure the knocking was from inside the engine??

Although prolly unlikely...did you check endplay in the crank? thrust bearing looks good??

Any of the flywheel/clutch bolts loose??

Have you checked things with feelers and mics...or just eyeball'd?

Does it make the sound when you turn it over by hand??

Did you ensure the timing was correct??

Just tryin to get the ball rollin......

Maybe plastigauge all the bearings on the crank and rods, or it could have been a broken lifter or rocker?