Toyota AZ engine
This article needs additional citations for verification. (January 2019) (Learn how and when to remove this template message)
The Toyota AZ engine family is a straight-4 piston engine series. The AZ series uses an aluminium engine block with cast iron cylinder liners and aluminium DOHC cylinder heads. The engine series features many advanced technologies including slant-squish combustion chambers, offset cylinder and crank centers, and the VVT-i continuously variable intake valve timing system. The aluminium engine measures 626 mm (24.6 in) long, 608 mm (23.9 in) wide, and 681 mm (26.8 in) tall.
|Toyota AZ engine|
|Manufacturer||Toyota Motor Corporation|
|Displacement||2.0 L (1,998 cc)|
2.4 L (2,362 cc)
|Cylinder bore||86 mm (3.39 in)|
88.5 mm (3.48 in)
|Piston stroke||86 mm (3.39 in)|
96 mm (3.78 in)
|Valvetrain||DOHC 4 valves x cyl. with VVT-i|
|Compression ratio||9.6:1, 9.8:1, 11.0:1, 12.5:1|
|Supercharger||TRD (on Scion tC only)|
|Fuel system||Sequential MPFI|
D-4 direct injection
|Power output||145–211 hp (108–157 kW)|
|Torque output||190–257 N⋅m (140–190 lb⋅ft)|
|Length||626 mm (24.6 in)|
|Width||608 mm (23.9 in)|
|Height||681 mm (26.8 in)|
|Predecessor||Toyota S engine|
|Successor||Toyota AR engine|
The cylinder block is an open-deck, midi-skirt die-cast aluminium type with cast-in iron liners and a die-cast aluminium lower crankcase and a stamped oil pan. The forged steel crankshaft is fully balanced with eight counterweights and supported by five main bearings. A helical gear pressed in No. 3 counterweight drives twin contra-rotating balance shafts in the shaft housing within the lower crankcase.
The dual overhead camshafts are driven by a single-stage roller chain of 8 mm (0.31 in) pitch, enabling a narrow included valve angle of 27.5°. The camshafts act on four valves per cylinder via bucket tappets. As in the recent Toyota engine practice, no clearance adjusting shim is employed. Valve diameters are 34 mm (1.3 in) for intake and 29.5 mm (1.16 in) for exhaust, with 8 mm (0.31 in) lift for both intake and exhaust. The four-vane VVT-i device is fitted on the intake camshaft, altering timing by 50°. The valve cover is made of magnesium to save weight.
Fuel is injected sequentially via an ultra-fine-atomization injector with twelve small injection holes, each 0.18 mm (0.0071 in) in diameter. As in the smaller NZ engine, the new AZ adopts a plastic, built-up, and vibration-welded intake manifold integrating a large volume plenum chamber (3.5 L (210 cu in) volume including a 1.3 L (79 cu in) resonator). Exhaust manifolds are of tubular construction with integrated catalytic converters.
Excessive oil consumptionEdit
The 2AZ-FE engine in the 2007-2009 Camry may burn excessive oil and is involved in this lawsuit.  Other engines are also affected. If this Toyota engine is burning more than 1 US quart (946 ml) of oil in 1,200 miles (1,931 km), has less than 150,000 miles (241,402 km), and is less than 10 years old, Toyota service will perform a free oil consumption test to determine if your engine is affected. There are approximately 1,715,200 vehicles covered by this Warranty Enhancement Program.
The 1AZ-FE is a 2.0 L (1,998 cc) version. Output is 108 kW (145 hp) at 6000 rpm with 190 N⋅m (140 lb⋅ft) of torque at 4000 rpm for the Camry Aurion version. Rav4 and Ipsum engines were rated at 148–150 hp (110–112 kW) at 6000 rpm and 142 lb⋅ft (193 N⋅m) of torque at 4000 rpm.
The 1AZ has a total displacement of 2.0 L (1,998 cc) with 86 mm × 86 mm (3.39 in × 3.39 in) bore and stroke, and a compression ratio of 9.6:1.
The 1AZ-FSE is a 2.0 L (1,998 cc) version. Bore and stroke is 86 mm × 86 mm (3.39 in × 3.39 in), and a compression ratio of 11.0:1. Output is 149 PS (110 kW; 147 hp) at 5700 rpm with 196 N⋅m (145 lb⋅ft) of torque at 4000 rpm. The 1AZ-FSE features Toyota's D-4 direct injection system.
The 2AZ-FE is a 2.4 L (2,362 cc) version built in Japan (Kamigo Plant and by Toyota Industries Corporation), at TMMK in the USA and also built in China for select Scion xB models, obtains a total displacement of 2.4 L (2,362 cc) with 88.5 mm × 96 mm (3.48 in × 3.78 in) bore and stroke, with a compression ratio of 9.6:1. Output is 160 hp (119 kW) at 5600 rpm; 220 N⋅m (162 lb⋅ft) of torque at 4000 rpm.
Later versions of the 2AZ-FE engine were upgraded with 9.8:1 compression ratio, a slightly more aggressive intake cam profile, 6500 rpm redline, and piston oil squirters. These later versions are rated at 161 hp (120 kW) in the Scion tC, 177 hp (132 kW) in the RAV4, and 158 hp (118 kW) in the Camry, Corolla XRS, Scion xB, and 170 hp (127 kW) for the Previa/Estima. However, these later 2AZ-FE models were the first to be rated under the new SAE J1349 standard. The new standard usually produces more conservative numbers, though no definitive comparison is available since the two versions were never tested by the same standard. The RAV4 uses a different timing chain cover from the Camry, they can however be interchanged.
A TRD supercharger was available for the Scion tC until Spring 2009.
There have been complaints of this engine "burning oil" in North America, with the issue starting after 45,000 miles (72,000 km), though mostly after 60,000–75,000 miles (97,000–121,000 km). Piston ring design has been identified as a potential problem. Toyota has issued a TSB (Technical service bulletin) TSB #0094-11 in August 2011 but has not issued a recall. Alternative theories point to a head gasket problem: the 2AZ-FE aluminum block threads may wear out on the back three middle bolts (closest to firewall). Check TSB SB-0015-11.
There are several class-action lawsuits underway regarding this issue. In January 2015, Toyota North America issued extended warranty notification (ZE7) for this issue for Toyota North America vehicles only.
The 2AZ-FSE is a 2.4 L (2,362 cc) version. Bore and stroke is 88.5 mm × 96 mm (3.48 in × 3.78 in), and a compression ratio of 11.0:1. Output is 163 PS (120 kW; 161 hp) at 5800 rpm with 231 N⋅m (170 lb⋅ft) of torque at 3800 rpm. The 2AZ-FSE features Toyota's D-4 direct injection system.
The large valve overlap leads to a reduction in cylinder charge and reduced torque and power output, but efficiency is increased. This combination makes the 2AZ-FXE suitable for use only in hybrid vehicles, where peak torque and power demands can be met by the electric motor and battery.
Maximum output when used in the Camry hybrid is 211 hp (157 kW; 214 PS) at 6000 rpm with 257 N⋅m (190 lb⋅ft) of torque at 4400 rpm.