Engine description

How to use this Chapter

General information

This Part of Chapter 2 is devoted to in-vehicle engine repair procedures. All information concerning engine removal and refitting, and engine block and cylinder head overhaul can be found in Part B of this Chapter.

The following repair procedures are based on the assumption that the engine is installed in the vehicle. If the engine has been removed from the vehicle and mounted on a stand, many of the steps outlined in this Part of

Chapter 2 will not apply.

The Specifications included in this Part of Chapter 2 apply only to the procedures contained in this Part. Part B of Chapter 2 contains the Specifications necessary for cylinder head and engine block rebuilding.

Whilst all the engines covered by this manual are four cylinder, double overhead camshaft (DOHC) 16-valve units, they can be split into two categories: Those without variable valve timing, and those with (VVT-i).

The 1.3 litre 4E-FE and 1.6 litre 4A-FE engines fitted from 1997 to 2000 have fixed valve timing and a timing belt which drives the exhaust camshaft, which is geared to the intake camshaft.

The 1.4 litre 4ZZ-FE and 1.6 litre 3ZZ-FE engines fitted from 2000 have a variable valve timing unit fitted to the intake camshaft sprocket, and a timing chain driving both the camshafts. The engine management system adjusts the timing of the camshaft via a hydraulic control system (using engine oil as the hydraulic fluid). The timing is varied according to engine speed and load - retarding the timing at low and high engine speeds to improve low speed driveability and maximum power respectively. At medium engine speeds, the timings are advanced (the valves open earlier) to increase mid-range torque and to improve exhaust emissions.

On Non-VVT-i engines, the valve clearances

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