LSA Piston Oil Squirters
When GM designed the OEM supercharged variants of the LS platform, the LSA and LS9, they made a number of changes to handle the increase in output and thermal loads. Today we take a closer look at the piston engine oil squirters as fitted to both engines.
A disassembled OEM piston engine oil squirter. Note the banjo type fitting, o-ring gland, and oil passage through the thread/shank.
The oil squirters are tapped into the hydraulic valve lifter oil galleries that run the length of the block, directing a stream of engine oil underneath the crown of the reciprocating piston in each cylinder. The purpose of the design is to cool the piston, increasing performance and reliability. Depending on conditions, the piston crown can reach temperatures of 500 degrees C, where as engine oil temperature is around 120-130 degrees C, giving a large differential and potential for cooling.
An LSA block with the oil squirters removed. The squirters are tapped into the lifter oil galleries on each side of the block.
The heat is transferred from the piston crown to the engine oil. The LSA and LS9 equipped vehicles have a supplementary water/oil heat exchanger.