Problems With M44 Engine Rebuild

[dclaw]

I rebuilt my engine after having thrown a rod originally....

I bought a short block off ebay, it had a few issues with a missing oil squirter, oil pan gasket, the pickup needed to be cleaned out and it didnt have a rod bearing on the 2nd cylinder.....

The cylinder head was in good shape, so I ended up just replacing the 2 intake valves which were bent when I threw the rod before.

I got the engine back together, and I have a few issues.... there is a tick that gets louder when you give it gas, then quiets when I let off the gas.....

I've been told it's piston knock, but I can't even consider tearing down the engine again to check this out... let alone possibly having to replace the pistons/rods/crank....

so, the question is....

is it possible it could be anything else? could it simply be lifter noise? may I just need to add some spacers between the valves and cam?

or... if it is piston knock.... do I need to tear down the engine and replace the pistons and/or rods and crank?

and also, would I be able to simply replace the offending piston and rod?

would using heavier weight oil help at all? right now I'm using 15w30

and finally.... (sorry for so many questions)

does anyone have any real information on boring out the m44 block to 2.0 or even 2.1 liters? I know there was a company actually selling a bored out 2.1l m44 engine, though I've heard they no longer sell it, so if I'm going to have to replace the pistons/rods/crank anyway.... I'd rather just go ahead and go the distance.... because I have my e46 325i to drive full time anyway...

thank you for your comments and suggestions,

mike