Engine Mechanical - 2.0L Zetec: Overview Mazda Tribute I facelift

ENGINE GENERAL INFORMATION

The 2.0L Zetec engine is a four cylinder in-line engine with double overhead camshafts and 16 valves. The 16 valve cylinder head improves volumetric efficiency, particularly at high engine speeds.

The cylinder head is made of aluminum alloy and the cylinder block is made of cast iron.

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The spark plug is installed in the center of the roofshaped combustion chamber to ignite the air/fuel mixture in the combustion chamber. The central location of the spark plug causes the flame front to be evenly spread across the combustion chamber, which also reduces spark knock.

Both camshafts are driven by a shared timing belt, and operate four valves per cylinder by means of mechanical valve tappets. One valve spring on each valve is used to close the valve.

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An automatic timing belt tensioner makes sure of correct timing belt tension. An additional spring-loaded cam provides proper belt tension during operation. The belt tensioner can operate 30 degrees either side of its central position.

The basic adjustment of the belt tensioner can no longer be controlled after the aligning tools and adjusting pin have been taken out (the spring forces from the valve train exert pressure on the timing belt and alter the position of the belt tensioner).

The 2.0L Zetec engine is equipped with a glass fiber-reinforced plastic intake manifold. The intake manifold ports are designed so the intake paths are the same length for all the cylinders.

1. This gives the following advantages: reduced heat transfer to the injectors, thereby avoiding vapor locks lighter weight reduction of fuel deposits on the intake walls during cold starts less heating of the intake air when the engine is hot

The crankshaft runs on five bearings and has a counterweight for each cylinder. The central main bearing has two bearing half shells which guide the crankshaft along its axis as well as adjusting the end float.

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The connecting rods are numbered one to four starting at the timing belt end. It is practically impossible to mix up the connecting rod bearing caps and connecting rods since the connecting rod bearing caps are broken away from the connecting rod during production. The fracture profile of a connecting rod bearing cap therefore only fits one of the connecting rods.

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The purpose of the lower crankcase is to reduce engine vibrations. This further reduces the level of noise inside the vehicle. There is a metal gasket between the lower crankcase and the cylinder block.

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Lower crankcase spacer shims are used to even out any excessively large gaps between the transaxle and the lower crankcase (see Specifications).

The engine is closed off at the bottom with a pressed steel oil pan which is directly attached to the lower crankcase. It is sealed with a 3 mm (0.12 in) wide bead of sealer.

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This vehicle is equipped with

1. a V-ribbed serpentine accessory drive belt.
2. an automatic drive belt tensioner.

New drive belts must be of the same type as originally installed.

Check the drive belt condition at 160,934 km (100,000 miles) then after every 24,140 km (15,000 miles).

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1. Remove the right front wheel and tire.
2. Remove the bolts and the right front lower splash shield.
3. Rotate the accessory drive belt tensioner clockwise and remove the accessory drive belt.
4. To install, reverse the removal procedure.

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1. Remove the accessory drive belt. Refer to «ACCESSORY DRIVE BELT - 2.0L ZETEC»(ref-178563-S17746962342005061700000) .
2. Remove the bolts and the accessory drive belt tensioner.
3. To install, reverse the removal procedure.

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1. Remove the accessory drive belt. Refer to «ACCESSORY DRIVE BELT - 2.0L ZETEC»(ref-178563-S17746962342005061700000) .
2. Remove the bolt and the accessory drive belt idler pulley.
3. To install, reverse the removal procedure.

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1. Remove the air cleaner outlet pipe. Refer to AIR CLEANER OUTLET PIPE - 2.0L ZETEC .
2. Remove the ignition wires from the spark plugs.
3. Disconnect the throttle cables. Disconnect the cruise control actuator cable (if equipped). Disconnect the accelerator cable.
4. Disconnect the catalyst monitor and heated oxygen sensor electrical connectors. Detach the electrical connectors from the bracket.
5. Remove the wiring harness anchors from the valve cover studs and position the wiring harness aside.
6. Remove the valve cover. Remove the studbolts Remove the bolts. CAUTION: The valve cover sealing surfaces are soft materials. Do not use abrasive grinding discs to remove gasket material; only use manual scrapers. Do not scratch or gouge sealing surfaces or oil leaks may occur.
7. Clean and inspect the sealing surfaces of the valve cover and the cylinder head. Both surfaces must be clean and flat.
8. To install, reverse the removal procedure. Install a new valve cover gasket if damaged.

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1. Remove the timing belt. Refer to «TIMING BELT»(ref-178563-S27823183412005061700000) .
2. Remove the camshaft alignment tool. NOTE: Measure each valve's clearance at base circle with the lobe pointed away from the tappet, before removing the camshafts. Failure to measure all clearances prior to removing the camshafts will necessitate repeated removal and installation and wasted labor time.
3. Use a feeler gauge to measure each valve's clearance and record its location.
4. Remove the camshafts. Refer to «CAMSHAFTS»(ref-178563-S10974582402005061700000) . CAUTION: If the camshaft and valve tappets are to be reused, mark the location of the valve tappets to make sure that they are assembled in their original positions.
5. Remove the valve tappets from the cylinder head. NOTE: A midrange clearance is the most desirable: intake: 0.15 mm (0.006 inch) exhaust: 0.3 mm (0.012 inch) NOTE: Select tappets using this formula: tappet thickness = measured clearance plus the base tappet thickness minus most desirable thickness.
6. Select tappets and mark installation location.

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Note. Lubricate the valve tappets with SAE 5W-20 Motor Oil.

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1. Install the valve tappets.
2. Install the camshafts. Refer to «CAMSHAFTS»(ref-178563-S10974582402005061700000) .
3. Confirm each valve's clearance at base circle with the lobe pointed away from the tappet.
4. Install the camshaft alignment tool.
5. Install the timing belt. Refer to «TIMING BELT»(ref-178563-S27823183412005061700000) .

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1. Remove the camshafts. Refer to «CAMSHAFTS»(ref-178563-S10974582402005061700000) . CAUTION: If the camshaft and valve tappets are to be reused, mark the location of the valve tappets to make sure that they are assembled in their original positions.
2. Remove the valve tappets from the cylinder head.
3. Inspect the valve tappets. Refer to «HYDRAULIC LASH ADJUSTER - INSPECTION»(ref-178563-S30505324902005061700000) . NOTE: Make sure the valve tappets are installed in their original locations.
4. To install, reverse the removal procedure. Lubricate the valve tappet with SAE 5W-20 Motor Oil.

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1. Remove the spark plugs. Refer to SPARK PLUGS - 2.0L .
2. Remove the valve tappets. Refer to «VALVE TAPPETS»(ref-178563-S03544658762005061700000) . NOTE: If the air pressure fails to hold the valves closed while carrying out the following steps, valve or valve seat damage is indicated and the cylinder head must be removed. NOTE: Make sure the applicable piston is at the top of its stroke.
3. Install the air line with an adapter in the spark plug hole and turn on the air supply.
4. Install the special tools, compress the valve spring, and remove the valve spring retainer and valve spring.
5. Inspect the valve spring, valve spring retainer and valve spring retainer key. Install new parts as necessary. NOTE: If air pressure has forced the piston to the bottom of the cylinder, any loss of air pressure will allow the valve(s) to fall into the cylinder. A rubber band, tape or string wrapped around the end of the valve stem will prevent this from happening.
6. Use the special tools to remove the valve stem seal.