302 knocking

Could someone give me some advice please.
I've only got 300 miles on my rebuilt (by myself) 302 and I've just noticed a knocking from the engine when starting from cold. It's coming from inside the centre of the engine somewhere but it's difficult to know where. When it's warm it's quiet but something needs sorting. Whats the best way to diagnose the knock?
It's been rebuilt with reground crank, 30thou rebore, performer plus cam and standard (but ported) heads.
I would guess that I may have a Camshaft problem but is there some way to tell without pulling the whole engine out?
When I started it for the first time I had the oil filter lines round the wrong way and for a couple of seconds it ran with no oil (oops) is this whats done it?
What else could the rattling be?
Any advice greatly appreciated.
Simon

Sounds like the pistons or a piston is rattling in the bore when cold. You didn't say what kind of pistons you used during the rebuild or the clearances for the pistons. BTW, this is not an uncommon problems with an engine with loose piston to bore tolerances.

Have you changed the oil yourself since the rebuild? Did you notice a silvery sheen on top of the oil? Maybe some flakes in the bottom of the oil drain pan? This would be an indication of other problems that might cause the knock if it isn't the pistons to bore clearances.
[addsig]

I was just about to change the oil when I noticed the noise.
Ive found out that the knocking is in time with the crankshaft NOT the camshaft, so presume it's a big end/main bearing problem. Is it possible to renew both just by dropping the sump?
Thanks

yes it's possible to change both, so long as the crank/block/rods are not damaged. I would also check the clearances while your in there. FYI a good rule of thumb on engine noises is generally if it's a main bearing it will make a "thud" noise, just like hitting the end of the crank with a hammer. A rod is more of a dull tapping noise that most often makes it's noise cruising at part throttle--usually goes away when accelerating/decelerating. I would be willing to bet that the pistons are making a bit of noise as you describe it going away when it warms up. Rods and mains wont usually go away with heat like that. Cam bearing damage will show low oil pressure, but usually wont make much noise.