1ZZ-FE Toyota I4 Engine

Introduction

First offered in Australia in 2000 in the Toyota MR2 Spyder, the 1ZZ-FE was a 1.8-litre four-cylinder petrol engine. Replacing the 1.6-litre 4A-FE and 1.8-litre 7A-FE cast iron engines, the 1ZZ-FE engine introduced all-alloy construction and, as a result, weighed 102 kg.

Like the related 2ZZ-GE, the 1ZZ-FE was a member of Toyota’s ZZ engine family. Whereas the 2ZZ-GE was developed for top-end power and had an 7800 rpm redline, the 1ZZ-FE was developed for economy and low-end torque. As such the 1ZZ-FE engine had a 6800 rpm redline.

From 2001 to 2007, the 1ZZ-FE engine was used in the E120 Corolla.

1ZZ-FE block

The 1794 cc 1ZZ-FE engine had an all-alloy cylinder block with 79.0 mm cylinder bores and a 91.5 mm stroke. Within the cylinders, there were chill-fitted cast iron liners that were 2.0 mm thick such that there were 8.5 mm spaces between the bores. The 1ZZ-FE block featured external ribbing for added rigidity, while the water-pump swirl chamber and the inlet passage to the pump were integrated into the block for compact packaging and mass reduction.

Crankshaft, connecting rods and pistons

The 1ZZ-FE engine utilised a forged crankshaft that had five journals and eight balance weights. The ladder-type crankshaft bearing caps had chill-fitted cast-iron inserts around the journal position. According to Toyota, these features provided greater strength, reduced noise, greater rigidity for the coupling to the transaxle and resistance from heat deformation. Furthermore, the oil-filter bracket, air conditioner compressor bracket and rear oil-seal retainer were integrated into the bearing cap to reduce the number of parts. Passage holes were provided in the crankshaft bearing area of the cylinder block for better airflow at the bottom of the cylinder and reduced back pressure at the bottom of the piston.

To reduce reciprocating mass and friction, the 1ZZ-FE engine had narrow and lightweight connecting rods which featured nutless-type plastic region tightening bolts. The pistons were made from an aluminium alloy and used full floating-type piston pins.

Cylinder head

The 1ZZ-FE engine had an all-alloy cylinder head with double overhead camshafts (Toyota’s ‘twin cam’ design) and four valves per cylinder that were actuated by shimless bucket-type tappets. The camshaft was driven by an 8 mm pitch roller chain which featured a lubricating oil jet and auto tensioner.

The 1ZZ-FE engine had a narrow valve included angle of 33.1 degrees. While the intake valves had a 32.0 mm diameter and 9.3 mm valve lift, the exhaust valves had a 27.5 mm diameter and 8.4 mm lift.

The 1ZZ-FE engine featured ‘laser-clad valve seats’ whereby the valve seats were made by welding high-resistance material into the port, with the valve seat then machined into that material. Compared to a conventional shrink-fit valve seat, the thinner laser-clad valve seats provided greater air flow and improved cooling around the valves.

Intelligent variable valve timing (VVT-i)

For the 1ZZ-FE engine, Toyota’s ‘variable valve timing with intelligence’ (VVT-i) provided continual variations of the intake valve timing according to engine speed, throttle position, inlet camshaft angle, engine coolant temperature and intake air volume.

For the ZZW30 MR2 Spdyer, inlet camshaft timing (and hence valve overlap) could be varied over a range of 43 degrees relative to crankshaft angle; maximum valve overlap was 50 degrees. For the E120 Corolla, inlet camshaft timing could be varied over a range of 40 degrees relative to crankshaft angle and maximum valve overlap was 44 degrees.

VVT-i was controlled by the ECU and implemented via an oil-pressure activated ‘push-push’ type system. Specifically, the hardware for the VVT-i system consisted of:

• A camshaft timing oil control valve – mounted adjacent to the inlet camshaft gear wheel – that was controlled via a coil and plunger by the ECU. When the ECU sought to vary valve timing, it directed a signal to the spool-type oil control valve to provide oil pressure to either the ‘advance’ or ‘retard’ side of the four vane chambers; and,
• A VVT-i controller mechanism that consisted of a housing on the front of the timing wheel – driven via the timing chain – and a four-bladed vane that was coupled with the intake camshaft.

Inlet cam timing was set to the maximum retard position for engine start-up, operation at low engine temperature, idle and engine shut-down. To prevent any knocking noise, a locking pin in the controller locked the camshaft timing in the maximum retard position for engine start-up and immediately thereafter until oil pressure was established.

Intake and exhaust

For efficient engine breathing, the 1ZZ-FE engine had long and straight intake ports. Furthermore, the inlet system was made of plastic to reduce heat transfer from the engine to the inlet charge. Within the air intake chamber, a resonator was used to optimise the intake pulsation and thereby improve engine performance in the mid-speed range.

Injection

The 1ZZ-FE engine had sequential electronic fuel injection (EFI) with twelve (12) injector nozzles mounted in the inlet ports (to minimise cylinder wall wetting). An L-type hot-wire meter was used to measure air flow. The ‘Toyota Direct Ignition’ system was a distributorless, coil-on-plug system which featured electronic spark advance with a knock control system.

The combustion chambers had a pentroof design, while the piston crowns had a ‘tapered squish’ design to improve thermal efficiency and reduce the likelihood of engine knock (pre-ignition). The squish angle was shaped obliquely along the wall surface of the combustion chamber to improve airflow, promote swirl and enhance flame travel. The 1ZZ-FE engine had a compression ratio of 10.0:1.

Exhaust

The 1ZZ-FE engine had a stainless steel exhaust manifold. The E120 Corolla had three-way catalytic converters that were located downstream of the exhaust headers. Unlike the Corolla, the ZZW30 MR2 Spyder had a dual exhaust system that fed into two three-way catalytic converters, then fed into a dual flexible pipe to a third three-way catalytic converter and then to the muffler.