Φραγμός μηχανών αυτοκινήτων αλουμινίου για τη TOYOTA η 1az-???????? TOYOTA XA20 RAV4 2000-2005

Introduction :

The 1AZ has aluminum cylinder block with cast iron liners. It features offset cylinder and crank centers. The
 

engine got the forged steel crankshaft, fully balanced by eight counterweights. The crankshaft is attached to
 

the block by five main bearings. Between first and second bearings there is a gear driven two balancing

shaft in the lower aluminum crankcase. The applying of balancing shafts was a big step in reduction of

engine vibration. Helical gears are made from polymeric material for the reduction of noise.
 

On top of the block there is aluminum DOHC 16-valve cylinder head. The intake camshaft is equipped with

VVTi system (Toyota variable valve timing system), altering timing by 50 deg. Camshafts are driven by a

single-stage roller timing chain. The angle between intake valves and exhaust valves is 27.5 deg. Intake

valve diameter is 34.0 mm (1.3 in), and for exhaust valve - 29.5 mm (1.2 in). Valve lift is 8.0 mm (0.3-in) for

both valve types. There are not hydraulic lifters.
 

The engine equipped with sequentially injected fuel system. Each fuel injectors has twelve small injection

holes (0.18 mm or 0.01 in). The intake manifold is made from plastic. The exhaust manifold and catalytic

converter is one unit.
 

Compare to predecessor, the 1AZ has high efficiency and fuel economy, low noise and vibration levels, light

weight and compact design, good reliability. The engine has older brother the 2AZ-FE. The 1AZ is

superseded by the newest 3ZR-FE engine since 2007.