NZ can be considered the most long-lived of the current series. Introduced first in 1997, it used for new models even in mid-2010's. This review, beside AZ and ZZ ones, will be boring - but it's one of the main series advantages.
Oddly enough, but the first in NZ series was the specific "hybrid" modification, which had quite a few differences from the followed traditional versions - from "Atkinson cycle" and compression ratio to initially implemented ETCS. 1NZ-FXE could be called - the first engine of "third wave", the first mass engine with chain timing drive (after a long pause), the first engine with modern VVT... However, we will not change out principle in relation to the hybrids - "aut nihil".
1NZ-FE - transverse, with traditional multipoint injection, for initially FF cars. Installed in: Allion/Premio 240, Bb 30, Corolla/Fielder/Runx/Allex 120, Corolla Spacio 120, Funcargo, Ist 60, Platz, Porte 10, Probox/Succeed, Ractis 100 (4WD), Raum 20, Scion xA 60, Scion xB 30, Sienta (4WD), Vios 150, Vitz 10, Will Cypha, Will VS, Yaris/Echo 10, Yaris 90..130..150, Yaris Verso 20. Note - the models initially received type'99, was equipped with it until production end, even after appearing of type'03 (exception - Corolla NZE121).
2NZ-FE. Installed in: Bb 30, Belta, Corolla 120, Funcargo, Ist 60, Probox/Succeed, Vios 90..150, Vitz 10..90, Will Cypha, Yaris 10..90..130..150.
The cylinder block - aluminum "open deck" with thin cast iron liners. The liners are fused into block and their special rough outer surface promotes strong connection. Of course, no overhaul with reboring provided. The massive alloy crankcase mounted to block also performs the function of the sump upper part.
Forged steel crankshaft with 5 journals and 4 balance weights is held by individual main bearing caps. The axis of the crankshaft has been shifted by 12 mm relative to the cylinder axis lines ("desaxage"), thus reducing the lateral component of the force exerted by the piston to the cylinder wall, reducing wear.
Pistons - aluminum, moderately cut skirt with a friction reducing polymer coating (LFA - Low Friction Resin with Alumina). Disadvantage - press-fit piston pins, not full-floating type, although in practice it is still not caused real problems.
Cylinder head of traditional design, with standard valve seats and holes for injectors.
Timing drive - 16-valve DOHC, driven by single-row roller chain (pitch 8 mm), with hydraulic tensioner (with ratchet mechanism) and lubricated by separate oil nozzle. The valve clearance is adjusted by a set of tappets, without adjusting washers or lash adjusters.
There is VVT (variable valve timing system) sprocket on the inlet camshaft, the range - 40°.
For some regions specific modifications of 2NZ-FE was produced - for leaded gasoline, without VVT, without converter and relative components.
Trochoid oil pump in chain cover is driven directly by the crankshaft. The oil filter is located vertically under the engine.
Система охлаждения кл The cooling system is classic for the 3rd wave engine: pump drive by serpentine belt, "cold" (80-84°C) mechanical thermostat, heated throttle body.
Intake and exhaust
New manifolds location: plastic (to reduce the weight and reduce heating of the inlet air) intake - front, outlet - behind.
Fuel injection system
The control system - "L-type SFI", with mass air flow sensor (MAF) "hot wire" type, combined with intake air temperature sensor.
Fuel injection - traditional multipoint, sequential under normal conditions. In some conditions (low temperature and low speed) paired injection can be performed. In addition, injection can be also performed synchronized (once per cycle at the same position of the crankshaft, with managed time of injection) or unsynchronized (by all injectors simultaneously).
Fuel system - without a return line, with the pressure regulator and the fuel filter built in pump module, the fuel pressure - about 325 kPa. Pulsation damper mounted on fuel rail.
The injectors with multi-hole nozzl are used to improve dispersion of fuel.
Throttle drive - mechanical, idle speed control - classic "rotary solenoid".
Oxygen sensor (89465) installation variants - upstream catalyst (domestic market) or upstream and downstream catalyst (overseas markets).
Ignition system - DIS-4 (separate coil with integrated igniter for each cylinder). Spark plugs - ordinary (Denso K16R-U11, NGK BKR5EYA11).
Auxiliary drive - by single serpentine belt, without tensioner (tension adjusting - by alternator moving).
- Air-fuel ratio (AFS) sensor (89467) upstream catalyst and oxygen sensor (89465) downstream (European and North American markets).
- "Flat" piezoelectric knock sensor was introduced, unlike the old type of resonant knock sensors it feels a wider range of vibration frequencies.
- Spark plugs with "iridium" center electrode (Denso SK16R11).
Domestic market models appeared after second half of 2003 (except Porte 10, 4WD Sienta & Ractis 100) was equipped with seriously modified engine.
- There are hydraulic lash adjusters and roller rockers in the valve mechanism. Significantly (from 33 to 21°) reduced angle between valves.
- In the lubrication system new oil path was provided - oil supply to lash adjusters and rockers.
- The cooling system was added with transmission fluid heater (for CVT) and EGR cooler. More "hot" (88°C) thermostat was applied.
- All engines was equipped with ETCS, EGR and electronically controlled fan, new models launched since 2005 was received with AFS sensor and flat knock sensor. The fuel rail serves as a pressure pulsation damper. Spark plugs - "iridium", with a long threaded portion (Denso FK20HR11, NGK ILFR6D11).
EGR system. System is used to reduce combustion temperature, decrease content of nitrogen oxides in the exhaust gases, reduce pumping losses at the inlet.
Exhaust gases from the exhaust manifold pass through a cooler and via channel in the cylinder head flows to the valve. EGR valve is driven by a stepper motor.
Exhaust gases from the valve flows into EGR manifold, which uniforms stream of gases in each cylinder.
This "well-forgotten old" solution was serious deterioration for 1NZ-FE. Technology of engine self-poisoning by exhaust gas and soot deposits in the intake - is unambiguous evil, especially for small-displacement gasoline engine. At the first opportunity in almost any car EGR line should be plugged, but in this case simple solution will not work - Toyota provided the system operation control by EGR temperature sensor.