Pull all the pistons and check for cracked skirts, worn out piston pins, etc. Pitted cylinders will cause oil consumption and compression blow-by, not a knock. If you choose to hone the cylinders and re-ring without boring the cylinders for new pistons, be sure to scrub the cylinder walls thoroughly with hot soapy water and a stiff-bristle brush. I wore out a brand new set of rings in 2500 miles once, because of an inadequate cleanup after honing.
Jerry
