ENGINE UNIT DETAILS


  1. CONSTRUCTION


    1. Cylinder Head Cover Sub-assembly


      1. Lightweight yet high-strength aluminum cylinder head cover sub-assemblies are used.

      2. An oil delivery pipe is installed inside each cylinder head cover sub-assembly. This ensures lubrication to the sliding parts of the valve rocker arm sub-assemblies, improving reliability.

        A01FBPRE01
        Text in Illustration
        *1 Oil Delivery Pipe *2 Cylinder Head Cover Sub-assembly
        *3 Cylinder Head Cover Gasket - -

    2. Cylinder Head Gasket


      1. Steel-laminate type cylinder head gaskets are used. A shim is used around the cylinder bore of each gasket to help enhance sealing performance and durability.

        A01FBV0E02
        Text in Illustration
        *1 Shim - -
        *a For Right Bank *b For Left Bank
        *c A - A Cross Section - -
        A01FCE5 Engine Front - -

    3. Cylinder Head Sub-assembly


      1. The cylinder head structure is simplified by separating the cam journal portion (camshaft housing sub-assembly) from the cylinder head.

      2. The cylinder head, which is made of aluminum, contains pentroof-type combustion chambers. The spark plug is located in the center of the combustion chamber in order to improve the engine's anti-knock performance.

      3. A taper squish combustion chamber is used to improve anti-knock performance and intake efficiency. In addition, engine performance and fuel economy are improved.

      4. The port configuration is an efficient cross-flow type in which the intake ports face the inside of the V bank and the exhaust ports face the outside.

      5. A siamese type intake port is used. The port diameter gradually decreases toward the combustion chamber to optimize the airflow speed and intake pulsation.

        A01FCD5E01
        Text in Illustration
        *1 Intake Valve *2 Spark Plug Hole
        *3 Exhaust Valve *4 Camshaft Housing
        *a Bottom Side View *b A - A Cross Section
        *c Taper Squish Area - -
        A01FC4S Intake Port A01FBVW Exhaust Port

        Tech Tips

        The difference between a siamese type intake port and an independent type one is shown in the illustration.

        A01FC8LE03
        Text in Illustration
        *A Siamese Type *B Independent Type

    4. Cylinder Block Sub-assembly


      1. The cylinder block sub-assembly is made of aluminum alloy, thus making it lightweight.

      2. The cylinder block sub-assembly has a bank angle of 60°, a bank offset of 36.6 mm (1.441 in.) and a bore pitch of 105.5 mm (4.15 in.), resulting in a compact block (length and width) for its displacement.

      3. Installation bosses for the 2 knock control sensors are located on the inside of the left and right banks.

        A01FCE0E02
        Text in Illustration
        *a Knock Control Sensor Boss - -

      4. A water passage has been provided between the cylinder bores. By allowing the engine coolant to flow between the cylinder bores, this construction enables the temperature of the cylinder walls to be kept uniform.

        A01FC6FE01
        Text in Illustration
        *a Water Passage - -

      5. A compact block has been achieved by producing the thin cast-iron liners and cylinder block sub-assembly as a unit. It is not possible to rebore a block which uses this type of liner.

      6. The liners are a spiny-type, which have been manufactured so that their casting exterior forms a large irregular surface in order to enhance the adhesion between the liners and the aluminum cylinder block. The enhanced adhesion helps improve heat dissipation, resulting in a lower overall temperature and reduced heat deformation of the cylinder bores.

        A01FC08E01
        Text in Illustration
        *1 Liner *2 Cylinder Block
        *a Irregularly Shaped Outer Casting Surface of Liner *b A - A Cross Section

    5. Piston


      1. The pistons are made of aluminum alloy.

      2. The top of the pistons use a taper squish shape to achieve fuel combustion efficiency.

      3. The piston skirt is coated with resin to reduce friction losses.

      4. The groove of the top ring is coated with alumite to ensure abrasion resistance.

      5. By increasing the machining precision of the cylinder bore diameter in the block, only one size piston is required.

        A01FC9ZE01
        Text in Illustration
        *a Taper Squish Shape - -
        A01FBVW Resin Coating A01FC4S Alumite Coating

    6. Connecting Rod Sub-assembly


      1. Connecting rod sub-assemblies that have been forged for high strength are used for weight reduction.

      2. Knock pins are used at the mating surfaces of the connecting rod caps to minimize the shifting of the connecting rod caps during assembly.

      3. Nutless-type plastic region tightening bolts are used on the connecting rod sub-assemblies for a lighter design.

      4. Aluminum bearings are used for the connecting rod bearings.

      5. The connecting rod bearings are reduced in width to reduce friction.

        A01FBQBE01
        Text in Illustration
        *1 Connecting Rod *2 Knock Pin
        *3 Plastic Region Tightening Bolt *4 Connecting Rod Bearing
        A01FC4S Resin Coating - -

    7. Crankshaft


      1. A crankshaft made of forged steel, which excels in rigidity and wear resistance, is used.

      2. The crankshaft has 4 main bearing journals and 5 balance weights.

        A01FBQ0E01
        Text in Illustration
        *1 No. 1 Journal *2 No. 2 Journal
        *3 No. 3 Journal *4 No. 4 Journal
        *5 Balance Weight - -
        A01FCE5 Engine Front - -

    8. Crankshaft Bearing and Crankshaft Bearing Cap


      1. The crankshaft main bearings are made of aluminum alloy.

      2. The crankshaft bearings are reduced in width to reduce friction. The bearing lining surface is coated with resin to improve wear and seizure resistance.

      3. The upper crankshaft bearings have an oil groove around the inside circumference.

      4. The crankshaft bearing caps are tightened using 4 plastic region tightening bolts for each journal. In addition, each cap is tightened laterally to improve its reliability.

        A01FBMLE01
        Text in Illustration
        *1 Plastic Region Tightening Bolt *2 Crankshaft Bearing Cap
        *3 Seal Washer *4 Upper Crankshaft Bearing
        *5 Lower Crankshaft Bearing - -
        *a Oil Groove - -
        A01FC4S Resin Coating - -

    9. Crankshaft Pulley


      1. The rigidity of the crankshaft pulley with its built-in torsional damper rubber reduces noise.

        A01FBZFE03
        Text in Illustration
        *1 Torsional Damper Rubber - -

    10. Oil Pan


      1. The No. 1 oil pan is made of aluminum alloy.

      2. The No. 2 oil pan is made of steel.

      3. The No. 1 oil pan is secured to the cylinder block sub-assembly and the transmission housing to increase rigidity.

      4. On 2WD models, the oil filter case is integrated with the No. 1 oil pan.

        A01FBRGE01
        Text in Illustration
        *A 2WD Models *B AWD Models
        *1 No. 1 Oil Pan *2 No. 2 Oil Pan
        *3 Oil Filter Case - -

    11. Valve Mechanism


      1. Each cylinder of this engine has 2 intake valves and 2 exhaust valves. Intake and exhaust efficiency is increased due to the larger total port areas.

      2. This engine uses valve rocker arm sub-assemblies with the built-in needle bearings. This reduces the friction that occurs between the cams and the valve rocker arm sub-assemblies that push the valves down, thus improving fuel economy.

      3. Valve lash adjuster assemblies, which maintain a constant zero valve clearance through the use of oil pressure and spring force, are used.

      4. The intake camshafts are driven by the crankshaft via the primary timing chain. The exhaust camshafts are each driven by the intake camshaft of their respective bank via a secondary chain.

      5. This engine has the Dual Variable Valve Timing-intelligent (Dual VVT-i) system which controls the intake and exhaust camshafts to provide optimal valve timing in accordance with to driving conditions. With this, lower fuel consumption, higher engine performance, and fewer exhaust emissions have been achieved.

        A01FBU8E01
        Text in Illustration
        *1 Primary Timing Chain *2 Secondary Timing Chain
        *3 No. 2 Camshaft (Exhaust) *4 No. 1 Camshaft (Intake)
        *5 No. 3 Camshaft (Intake) *6 No. 4 Camshaft (Exhaust)
        *7 Valve Rocker Arm Sub-assembly *8 Valve Lash Adjuster Assembly
        *9 Valve - -
        A01FC1FE01

    12. Camshaft


      1. The camshafts are made of cast iron alloy.

      2. Oil passages are provided on the intake and exhaust camshafts in order to supply engine oil to the VVT-i system.

      3. Camshaft timing gear assemblies (LH and RH) are installed on the front of the intake and exhaust camshafts to vary the timing of the intake and exhaust valves.

      4. Together with the use of the valve rocker arm sub-assemblies, the cam profile has been modified. This results in increased valve lift when the valve begins to open and as it finishes closing, helping to achieve enhanced output performance.

        A01FC0TE01
        Text in Illustration
        *1 Camshaft Timing Gear Assembly (Exhaust RH) *2 No. 2 Camshaft (Exhaust)
        *3 No. 1 Camshaft (Intake) *4 Timing Rotor
        *5 Camshaft Timing Gear Assembly (Intake RH) *6 Camshaft Timing Gear Assembly (Intake LH)
        *7 No. 3 Camshaft (Intake) *8 No. 4 Camshaft (Exhaust)
        *9 Camshaft Timing Gear Assembly (Exhaust LH) *10 Modified Profile of Camshaft Lobe
        *a Increased Valve Lift - -

    13. Camshaft Timing Gear Assembly (Intake)


      1. This controller consists of an outer housing driven by the timing chain sprocket, and a vane coupled to each camshaft.

      2. The intake side uses a camshaft timing gear assembly with 3 vanes.

      3. When the engine stops, each intake side camshaft timing gear assembly is locked at the most retarded angle by its lock pin. This ensures excellent engine startability.

      4. The oil pressure sent from the advance or retard side passages of the intake camshafts causes rotation of the vane relative to the timing chain sprocket, to vary the valve timing continuously.

        A01FBN1E07
        Text in Illustration
        *1 Lock Pin *2 Timing Rotor
        *3 Outer Housing *4 Vane (Coupled to Intake Camshaft)
        *5 Timing Chain Sprocket *6 Intake Camshaft
        *a Engine Operating *b Engine Stopped
        A01FCE5 Oil Pressure - -

    14. Camshaft Timing Gear Assembly (Exhaust)


      1. This controller consists of an outer housing that is driven by the timing chain sprocket, and a vane that is coupled to each camshaft.

      2. The exhaust side uses a camshaft timing gear assembly with 4 vanes.

      3. When the engine stops, the exhaust side camshaft timing gear assembly is locked at the most advanced angle. This ensures excellent engine startability.

      4. The oil pressure sent from the advance or retard side passages of the exhaust camshafts causes rotation of the vane relative to the timing chain sprocket, to vary the valve timing continuously.

      5. An advance assist spring is provided on the exhaust side camshaft timing gear assembly. This helps to apply torque in the advance angle direction so that the vane lock pin securely engages with the housing when the engine stops.

        A01FBNNE01
        Text in Illustration
        *1 Outer Housing *2 Vane (Coupled to Exhaust Camshaft)
        *3 Lock Pin *4 Timing Chain Sprocket
        *5 Exhaust Camshaft - -

    15. Chain Sub-assemblies and Chain Tensioner Sub-assemblies


      1. The primary and secondary chains are roller chains with a pitch of 9.525 mm (0.375 in.).

      2. All chain sub-assemblies are lubricated by an oil jet.

      3. A chain tensioner is provided for each primary timing chain and secondary timing chain in each bank.

      4. Both types of chain tensioner use a spring and oil pressure to maintain proper chain tension at all times. They suppress noise generated by the chains.

      5. The chain tensioner sub-assembly (primary) is a ratchet type with a non-return mechanism.

        A01FBPIE01
        Text in Illustration
        *1 Chain Tensioner (Secondary) *2 Ball
        *3 Ball Spring *4 Main Spring
        *5 Plunger *6 Chain Tensioner (Primary)
        *7 Spring *8 Plunger
        *9 Cam Spring *10 Cam
        *11 Idle Sprocket Assembly *12 Secondary Timing Chain
        *13 Primary Timing Chain *14 Chain Damper
        *15 Chain Slipper - -

    16. Valve Lash Adjuster Assembly


      1. The valve lash adjuster assemblies, which are located at the fulcrum (pivot point) of the valve rocker arm sub-assemblies, each consist primarily of a plunger, plunger spring, check ball, and check ball spring.

      2. Both the engine oil that is supplied by the cylinder head sub-assembly and the built-in spring actuate the valve lash adjuster assembly. The oil pressure and the spring force that act on the plunger push the valve rocker arm sub-assembly against the cam, in order to adjust the clearance between the valve stem and the valve rocker arm sub-assembly. This prevents the generation of noise during the opening and closing of the valves. As a result, engine noise is reduced.

        A01FBXQE01
        Text in Illustration
        *1 Plunger *2 Oil Passage
        *3 Check Ball *4 Check Ball Spring
        *5 Plunger Spring *6 Valve Lash Adjuster Assembly
        *7 Oil Passage *8 Cam
        *9 Valve Rocker Arm Sub-assembly - -

    17. V-ribbed Belt


      1. Accessory components are driven by a serpentine belt consisting of a single V-ribbed belt.

        It reduces the overall engine length, weight and number of engine parts.

      2. An automatic tensioner eliminates the need for tension adjustment.

        A01FCENE01
        Text in Illustration
        *1 Belt Idler Pulley *2 Generator Pulley
        *3 Water Pump Pulley *4 Idler Pulley for Automatic Tensioner
        *5 Air Conditioning Compressor Pulley *6 Crankshaft Pulley

    18. V-ribbed Belt Tensioner Assembly


      1. The tension of the V-ribbed belt is properly maintained by the tension spring that is enclosed in the belt tensioner.

        A01FBQME01
        Text in Illustration
        *1 Idler Pulley *2 Spring
        *3 Arm *4 Bracket
        *5 Fulcrum - -
        *a Cross Section - -
        A01FCE5 Belt Tension Direction A01FC3K Belt Pulling Direction