Engine Component Description
Engine Component DescriptionBlock
The engine is a water-cooled 6 cylinder V configuration with twin camshafts per cylinder head and 4 valves per cylinder. The angle between the banks of cylinders is 54 degrees. The cylinder block is a one-piece cast iron casting with cylinder bores cast into the block. Oil galleries for the lubrication system are also drilled into the block.
Cylinder Heads
The engine has 2 cylinder heads identified as the left bank (cylinders 2, 4, 6) and right bank (cylinders 1, 3, 5). Each cylinder head is cast in a light aluminum alloy and fastened to the cylinder block with non-reusable torque-to-yield bolts. The combustion chambers are hemispherical with 4 valves per cylinder and the spark plugs are located in the center. The intake and exhaust valves have chromium-plated stems. The exhaust valves are sodium filled for heat dissipation. The valve guides are pressed in the cylinder head and are not replaceable, but can be serviced by reaming the guides to an over-sized diameter and installing valves with over-sized stems.
Camshafts
Each cylinder head has twin overhead camshafts. A toothed belt drives the 4 camshafts with a self-adjusting belt tensioner. The belt assembly also includes 2 eccentric pulleys for timing adjustment. The camshaft sprockets on the left cylinder head are interchangeable, as are the sprockets on the right cylinder head. The camshafts are direct acting on the valves via hydraulic lifters. The hydraulic lifters adjust automatically to the change in length of the valves at different temperatures. The hydraulic lifters are supplied oil through oil galleries in the cylinder head.
Pistons and Connecting Rods
The pistons are made of light alloy and are coated with graphite. There are grooves for two compression rings and one scraper ring. The top compression ring is flat and molybdenum coated. The lower compression ring is wider than the upper compression ring and has an oil scraper function. The oil-scraper ring consists of 3 parts, upper oil control ring, expander, lower oil control ring. The 3.2L (LA3) piston pins are full floating and are retained by locking clips in the piston pin bore. Connecting rods are manufactured in one piece. The 2.6L (LY9) piston pins are press fit. The connecting rods are fractured at the connecting rod journal and then machined for the proper clearance. The connecting rod bearings are replaceable. Connecting rod bolts are non-reusable torque-to-yield bolts.
Crankshaft
The crankshaft is supported by 4 main bearings. The crankshaft bearing caps are retained by a crankshaft bearing bridge which stiffens the block. All main bearings are replaceable. The number 4 main bearing is the thrust bearing. The number 2 and number 3 main bearings have no grooves in the bearing caps. The crankshaft reluctor wheel is bolted to the crankshaft.
WHAT'S NEW
Torque Values and/or Fastener Tightening Strategies
Torque values and fastener tightening strategies are carryover from 2001 L81.
Changed Engine Specifications
- Crankshaft stroke has been changed.
- Cylinder bore has been changed.
New Sealants and/or Adhesives
- A pipe sealant type material is used on the thermostat housing bolts.
- A new anaerobic gasket marker is used on the engine oil cooler cover.
- A new anaerobic gasket marker is used on the oil pan.
Disassembly and Assembly Procedure Revisions
The majority of the disassembly and assembly procedures have been revised, due to the newly designed engine assembly.
Engine Mechanical Diagnostic Procedure Revisions
A new Engine Compression Test procedure has been added using a Tech 2.
New Special
Tools Required
- J-43276 Clutch Pilot Bearing Remover
A Component Comparison from the Previous Year
The 3.2 liter, LA3, and 2.6 liter, LY9, engines have replaced the 3.0 liter, L81 engine.
Some of the new features include:
- Cylinder bores have enlarged to 87.5 mm (3.45 inch) for the 3.2L and deceased to 83.2 mm (3.28 inch) for the 2.6L.
- Crankshaft stroke has been changed to 88 mm (3.47 inch) for the 3.2L and 79.6 mm (3.13 inch) for the 2.6L.
- The 3.2L has a forged steel crankshaft. - The 2.6L has pressed fit piston pins.
- A new oil filter adapter that allows room for the close-coupled catalytic converter.
- The ECM is now located on the right side camshaft cover.
- Multi-wall steel exhaust manifolds are used to decrease loss of exhaust gas heat.
- A new structural oil pan is used.
- Secondary Air Injection has been removed on both engines.
- Flywheel adapter and retainer has been deleted.
- A new engine block heater is being used.
- Timing belt idler pulley has been relocated, to minimize belt noise.