just started my cossie engine the othewr day that i have rebuilt and it is knocking it sounds just like a diesel, before i rebuilt this engine it was making this noise after just swapping the head but now i have replaced the crank,all bearings,bolts,rings,gakets, infact the only parts still from the old engine are the BLOCK,RODS AND PISTONS they are all in good nick.so the only reason i can see for the noise is that the TIMING.

i set the boittom pulley to the lug before the groove, the top pulleys to each other and the aux pulley to the middle of the half moon.
i'm sure this is right but i can't think what else it caqn be this engine has been killing me 4 nearly 2 years and there is not much else i can replace.

after it had made this noise before i noticed slight marks on the pistons from the valves ,but like i say the timing looks bob on..

maybe someone can shed some light on it.. cheers