Piston Cooling Nozzles

The Piston Oil Cooling Nozzles are built into the engine block by the BMW engine factory. The nozzle itself, consists of a check ball and a spring built into a small threaded housing. They are fitted directly into the main bearing support area of the block which accesses the main oil pressure supply. It requires approximately 1,7 Bar or 25 Psi of oil pressure to "unseat" the check ball, and a steady stream of oil from the nozzles continuously spray on to, and cools the underside of the piston crown.

There is no need for piston crown cooling when the engine is idling. The spring under the check ball will overcome the oil pressure and shut off the nozzle when approaching idle. This is to maintain safe idle oil pressure. We firmly belive that piston cooling nozzles is one of the more important aircraft engine safety factors, especially under continuous high loads, as aircraft engines most of the time is exposed to.