The hole in the rod is angled toward the cylinder wall to lubricate the piston skirt as it squirts oil onto the cylinder when the oil passage in the crankshaft lines up with the hole in the bearing and the rod. The hole in the rod is very tiny, about .020" or so. I use a pin vise and a # 60 drill bit to clean the hole in the rod during an overhaul, as they tend to get clogged with sludge and/or carbon deposits. Wrist pins are gravity-oiled from angled holes in the top of the pin bosses in the pistons that catch some of the oil scraped off the cylinder walls by the rings.

GMC engines have gun-drilled rods and pressure-lubricated wrist pins.
Jerry


"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!