G-Force Engine Development: Performance Modification: Piston Cooling Oil Jet

With increased horspower cames a natural, but hard to deal with side effect: HEAT! At heat IS power, it is necessary. However, there also comes a lot of excess heat that needs to be managed and disposed of, or in reality "transfered" away from components that it can damage. The hottest part of the engine is the combustion chamber. The piston is the bottom of the combustion chamber and the only part of the combustion chamber that is not cooled by the standard cooling system. The only place the heat can exit the pistin is through the piston rings into the cylinder walls, or through the wrist pins and down the connecting rods.

Many manufacturers put some kind of method to distribue oil to the bottom of the piston domes, as well as toward the wrist pins to get some cooling to these parts. However, when increasing the power, and the associated heat that comes with that power, the little oil jets are sometimes not enough. More modern high performance engines use much more direct piston cooling oil jets that squirt a direct jet of oil to the underside of the pistons. The increased oil flowing across the underside of the piston helps draw the heat out of the pistons and bring it down into the oil.

Agian, as heat is energy, and the Law of Conservation of Energy states that, "energy can neither be created or destroyed", the energy is only transfered to the engine oil, not removed. This means that it is now critical to continue to deal with the heat from there. We have installed HRC oil coolers that take the heat from the oil and transfer it to the cooling system through the water-cooled oil cooler. But the stock radiators are barely capable of dissipating the heat of a stock engine, let alone a highlyamodified engine. The quest for better radiators has also been a long one that could have its own "Part Evolution" page, but the final outcome were the radiators from Gerd in Gremany. finally, we can direct this offending energy all the way out of the engine and into the airstream.

Now that we have the energy path figured out, we needed to figure out how to get the oil to the bottom of the pistons. That took while to figure out, but once we stared at things long enough, with enough different eyes and minds together, the ideas were flowing. We would come in from the front of the crankcase and run small stainless oil tubes to the bottom of the cylinders. The front cylinders were easy. The rear cylinders were actually very tricky because the clearance was minimal and we didn't want the oil tubes to get caught on the spinning crankshaft. Very careful routing and securing of the rear tubes we were able get the oil jet right where we wanted it.

We started with AN-style -3 Bulkhead fillings and modified them to accept 2 1/8" O.D. Stainless Steel tubes side-by-side. Each fitting feeds oil through the front of the crankcase to the corresponding side of the engine (Left and Right sides). The tubes are then bent so that they clear the moving components of the engine while feeding the oil directly to the underside of the pistons.