Petro-Canada Lubricants’ Sentron SP 40 stationary gas engine oil is formulated with 0.75 percent sulfated ash and is designed for use in four-stroke stationary gas engines operating with steel pistons. According to the company, the oil’s thermal and oxidative stability prevents deposits in the top ring grooves of steel piston engines to reduce wear and increase engine durability, while its alkalinity retention extends drain intervals. The oil is also formulated to withstand high temperatures and pressures. Web: lubricants.petro-canada.com