Engine: Description and Operation
Engine Component Description (6.2L LS9)
The 6.2L LS9 Liter V8 Engine
The 6.2L Liter V8 engine is identified as RPO LS9.
Camshaft and Drive System
A billet steel 1 piece camshaft is supported by 5 bearings pressed into the engine block. The camshaft timing chain sprocket is mounted to the front of the camshaft and is driven by the crankshaft sprocket through the camshaft timing chain. The camshaft position (CMP) sensor lobes are incorporated into the front face of the camshaft sprocket with the CMP sensor mounted to the engine front cover. A timing chain tensioner is mounted to the front of the engine block above the crankshaft sprocket. The externally splined crankshaft sprocket is positioned to the crankshaft by a key and keyway. The crankshaft sprocket external splines drive the dual-rotor oil pump drive gears. A retaining plate mounted to the front of the engine block maintains camshaft location.
Crankshaft
The precision-balanced crankshaft is forged steel and is supported by 5 crankshaft bearings. The bearings are retained by forged steel crankshaft bearing caps, which are machined with the engine block for proper alignment and clearance. The crankshaft journals are undercut and rolled. The center main journal is the thrust journal. A crankshaft position (CKP) reluctor ring is press-fit mounted at the rear of the crankshaft. The reluctor ring is not serviceable separately.
Cylinder Heads
The cylinder heads are cast aluminum and include pressed-in-place powdered metal valve guides, 55 mm (2.19 in) diameter titanium intake valves, 40.4 mm (1.59 in) diameter hollow stem sodium-filled exhaust valves, and 66.85 cubic centimeter combustion chambers. Passages for the engine coolant air bleed system are at the front of each cylinder head. The valve rocker arm covers are retained to the cylinder heads by 4 center mounted rocker arm cover bolts.
To ensure sealing, M12 x 1.75 mm cylinder head bolts and a unique design seven layer, with four active layers, steel head gaskets are used.
Engine Block
The engine block is a cam-in-block deep skirt 90 degree V configuration with 5 forged steel crankshaft bearing caps. The engine block is cast aluminum with press-in-place cast iron cylinder liners. The 5 crankshaft bearing caps each have 4 vertical M10 and 2 horizontal M8 mounting bolts. The engine block and bearing caps are aligned by dowel pins retained in the caps. The camshaft is supported by 5 press-in-place camshaft bearings. Eight piston cooling oil nozzle assemblies are mounted between each of the opposing cylinders. The oil nozzles spray oil up the cylinder bore directing oil to the bottom of the pistons.
Exhaust Manifolds
The hydro-formed stainless steel exhaust headers are a 1 piece steel design with unique quad flow collector flanges. The exhaust manifolds direct exhaust gasses from the combustion chambers to the exhaust system. Each manifold also has an externally mounted heat shield that is retained by bolts.
Intake Manifold/Supercharger
Refer to Supercharger Description and Operation (Description and Operation).
Oil Pan
The structural dry-sump oil pan is cast aluminum. Incorporated into the design are the oil filter mounting boss, drain plug openings, oil pump screen, and internal oil passages. An external oil cooler assembly is mounted directly to the left side of the oil pan. The alignment of the structural oil pan to the rear of the engine block and transmission housing is critical.
Piston and Connecting Rod Assembly
The pistons are forged aluminum. The pistons use 2 compression rings and 1 oil control ring assembly. The piston is a low friction, lightweight design with a recessed top and barrel shaped skirt. The piston pins are chromium steel and are a full-floating design. The connecting rods are titanium alloy with press-in-place piston pin bushings. The connecting rod and rod cap are aligned by locating pins press-fit into the end of the rod. All applications use a piston with a graphite coated skirt.
Valve Rocker Arm Cover Assemblies
The valve rocker arm covers are cast aluminum and use a pre-molded silicon gasket for sealing. The ignition coils mount directly to the covers with no mounting bracket. Positive crankcase ventilation (PCV) fresh air passages are incorporated into both the left and right side covers. The cap on the right valve cover is not to be used for oil fill as oil is to be added into the dry-sump oil tank when required.
Valve Train
Motion is transmitted from the camshaft, through the hydraulic roller valve lifters and tubular pushrods, to the roller type rocker arms. The nylon valve lifter guides position and retain the valve lifters. The valve rocker arms for each bank of cylinders are mounted on pedestals or pivot supports. Each rocker arm is retained on the pivot support and cylinder head by a bolt. Valve lash is net build. The exhaust valves have sodium filled valve stems. The intake valves are a titanium design and have a rocker arm wear pad at the top of the stem.