This is a couple of Cummins ISL-G 8.9 liter inline 6-cylinder cylinder heads we rebuilt and overhauled with a complete valve job & surface. These heads are similar to the 8.3 liter C-Series 12-Valve Cummins diesel cylinder heads but they are actually ran on CNG (Compressed Natural Gas). The ISL-G Cummins is also an 8.9 liter inline 6 cylinder industrial engine. These Cummins ISL-G cylinder heads are often used for municipalities that operate buses, refuse trucks, garbage trucks, disposal trucks, and many other environmentally concerned operations. We first disassemble the cylinder heads and thermal clean them in our Bayco Oven. After thermal cleaning the heads they go into the Zero Blast-N-Peen Shotblaster. After shotblasting we perform a magnaflux to check for any visual cracks. Once no visual cracks are detected we put the cylinder heads in our custom special built pressure tester in order to pressurize the cylinder heads so we can check and inspect for any leaks from unseen cracks or porosity in the casting. Once the pressure test is passed the heads go into our Tobin-Arp seat-and-guide machine and we cut and machine the valve seats with 3-angle valve seat cutters. The heads then go onto our AMC surfacing and milling machine so we can surface and mill the surface / deck of the heads flat and square. The valves are all sandblasted in our sandblaster. After the valves are all cleaned we measure the valve stems in three spots for stem wear. The valves are then chucked up in our Sioux valve grinder and the faces of the intake and exhaust valves are all ground smooth and true. The valve springs are tumble cleaned in our tumbler and then they are checked for their free heights and pressures. The heads are then assembled with new positive Viton valve stem seals and checked with a final vacuum test to ensure that all the valves are seating and sealing on their valve seats properly. If you have any cylinder heads that need a valve job and surface, milling and surfacing, pressure testing and inspecting please look us up. Jimmy Ewing Motor Mission Machine & Radiator 5435 Desert Point Dr. Las Vegas, Nv. 89118 Phone: (702) 649-2366 or (702) 649-0648 Fax: (702) 649-4133 www.MotorMission.com