The Stovebolt Site Forums The Shop Area Engine Shop 38 engine

The oil pump supplies the main bearings (and camshaft bearings I believe) under direct pressure. The vast majority of the oil is pumped to the rear chamber of the oil distribution valve housing (just below the manifolds & between the exhaust pipe and engine block. When the oil reaches a given pressure the valve opens and allows the oil to enter the front chamber of the distribution valve. From there it splits. Most returns to the oil pan through the "squirters" in the pan. The rest travels up the 1/8" ID copper line, through the water jacket, up the right side of the block under the side cover, into the head and feeds the rocker arm assemblies. The squirters ride inside troughs in the pan. The rod caps have "dippers" on them that scoop oil out of the troughs at low speed. At higher engine speeds the oil pressure increases enough that the oil squirts out of the squirters into the path of the dippers which forces the oil into the rod bearings under increased pressure. It's amazing that such engineering works. I've read old magazine articles that say hod rodders of the era found the squirter system to be more trouble free than those that were converted to full pressure. The key was to replace the cast iron pistons to aluminum to reduce the force on the babbeted rods. Even more reliability was gained by adding harder bearing inserts to the babbeted rods. Big down side is no oil filter and the accessory filters of that era are a high bypass filter that allows most of the oil to bypass the filter.