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1 General information

Included in this portion of Chapter 2 are the general overhaul procedures for the cylinder head and internal engine components.

The information ranges from advice concerning preparation for an overhaul and the purchase of new parts to detailed, step-by-step procedures covering removal and installation of internal engine components and the inspection of parts.

The following Sections have been written based on the assumption that the engine has been removed from the vehicle. For information concerning in-vehicle engine repair, as well as removal and installation of the external components necessary for the overhaul, see Chapter 2A and Section 8 of this Chapter.

The Specifications included in this Part are only those necessary for the inspection and overhaul procedures which follow. Refer to Part A for additional Specifications.

2 Engine overhaul -

general information it with

1 It is not always easy to determine when, or if, an engine should be completely overhauled, as a number of factors must be considered.

2 High mileage is not necessarily an indication that an overhaul is needed, while low mileage does not preclude the need for an overhaul. Frequency of servicing is probably the most important consideration. An engine which has had regular and frequent oil and filter changes, as well as other required maintenance, should give many thousands of kilometers of reliable service. Conversely, a neglected engine may require an overhaul very early in its life.

3 Excessive oil consumption is an indication that piston rings, valve seals and/or valve guides are in need of attention. Make sure that oil leaks are not responsible before deciding that the rings and/or guides are worn. Perform a compression test, as described in Part A of this Chapter, to determine the likely cause of the problem.

4 Check the oil pressure with a gauge fitted in place of the oil pressure switch, and compare that specified. If it is extremely low, the main and big-end bearings, and/or the oil pump, are probably worn out.

5 Loss of power, rough running, knocking or metallic engine noises, excessive valve gear noise, and high fuel consumption may also point to the need for an overhaul, especially if they are all present at the same time. If a complete service does not remedy the situation, major mechanical work is the only solution.

6 A full engine overhaul involves restoring all internal parts to the specification of a new engine. During a complete overhaul, the pistons and the piston rings are renewed, and the cylinder bores are reconditioned. New main and big-end bearings are generally fitted; if necessary, the crankshaft may be reground, to compensate for wear in the journals. The valves are also serviced as well, since they are usually in less-than-perfect condition at this point. Always pay careful attention to the condition of the oil pump when overhauling the engine, and renew it if there is any doubt as to its serviceability. The end result should be an as-new engine that will give many trouble-free kilometers.

7 Critical cooling system components such as the hoses, thermostat and water pump should be renewed when an engine is overhauled. The radiator should be checked carefully, to ensure that it is not clogged or leaking. Also, it is a good idea to renew the oil pump whenever the engine is overhauled.

8 Before beginning the engine overhaul, read through the entire procedure, to familiarise yourself with the scope and requirements of the job. Overhauling an engine is not difficult if you follow carefully all of the instructions, have the necessary tools and equipment, and pay close attention to all specifications. It can, however, be time-consuming. Plan on the car being off the road for a minimum of two weeks, especially if parts must be taken to an engineering works for repair or reconditioning. Check on the availability of parts and make sure that any necessary special tools and equipment are obtained in advance. Most work can be done with typical hand tools, although a number of precision measuring tools are required for inspecting parts to determine if they must be renewed. Often the engineering works will handle the inspection of parts and offer advice concerning reconditioning and renewal.

9 Always wait until the engine has been completely dismantled, and until all components (especially the cylinder block/ crankcase and the crankshaft) have been inspected, before deciding what service and repair operations must be performed by an engineering works. The condition of these components will be the major factor to consider when determining whether to overhaul the original engine, or to buy a reconditioned unit. Do not, therefore, purchase parts or have overhaul work done on other components until they have been thoroughly inspected. As a general rule, time is the primary cost of an overhaul, so it does not pay to fit worn or sub-standard parts.

10 As a final note, to ensure maximum life and minimum trouble from a reconditioned engine, everything must be assembled with care, in a spotlessly-clean environment.

3 Engine removal -

methods and precautions

1 If you have decided that the engine must be removed for overhaul or major repair work, several preliminary steps should be taken.

2 Locating a suitable place to work is extremely important. Adequate work space, along with storage space for the car, will be needed. If a workshop or garage is not available, at the very least, a flat, level, clean work surface is required.

3 Cleaning the engine compartment and engine/transmission before beginning the removal procedure will help keep tools clean and organised.

4 An engine hoist or A-frame will also be necessary. Make sure the equipment is rated in excess of the weight of the engine. Safety is of primary importance, considering the potential hazards involved in lifting the engine/ transmission out of the car.

5 If this is the first time you have removed an engine, an assistant should ideally be available. Advice and aid from someone more experienced would also be helpful. There are many instances when one person cannot simultaneously perform all of the operations required when lifting the engine out of the vehicle.

6 Plan the operation ahead of time. Before starting work, arrange for the hire of or obtain all of the tools and equipment you will need. Some of the equipment necessary to perform engine/transmission removal and installation safely and with relative ease (in addition to an engine hoist) is as follows: a heavy duty trolley jack, complete sets of spanners and sockets (see Tools and working facilities), wooden blocks, and plenty of rags and cleaning solvent for mopping-up spilled oil, coolant and fuel. If the hoist must be hired, make sure that you arrange for it in advance, and perform all of the operations possible without it beforehand. This will save you money and time.

7 Plan for the car to be out of use for quite a while. An engineering works will be required to perform some of the work which the do-it-yourselfer cannot accomplish without special equipment. These places often have a busy schedule, so it would be a good idea to consult them before removing the engine, in order to accurately estimate the amount of time required to rebuild or repair components that may need work.

8 Always be extremely careful when removing and refitting the engine/transmission. Serious injury can result from careless actions. Plan ahead and take your time, and a job of this nature, although major, can be accomplished successfully.

Note: Such is the complexity of the power unit arrangement on these vehicles, and the variations that may be encountered according to model and optional equipment fitted, that the following should be regarded as a guide to

4.6 Label both ends of each wire and hose before disconnecting it the work involved, rather than a step-by-step procedure. Where differences are encountered, or additional component disconnection or removal is necessary, make notes of the work involved as an aid to refitting.

4 Engine -

removal and refitting

Note: Read through the entire Section before beginning this procedure. The factory recommends removing the engine and transmission from the top as a unit, then separating the engine from the transmission on the workshop floor. If the transmission is not being serviced, it is possible to leave the transmission in the vehicle and remove the engine from the top by itself, by removing the crankshaft pulley and tilting up the timing belt/ chain end of the engine for clearance.

Warning: These models are equipped with airbags. The airbag is armed and can deploy (inflate) anytime the battery is connected. To prevent accidental deployment (and possible injury), turn the ignition key to LOCK and disconnect the negative battery cable whenever working near airbag components. After the battery is disconnected, wait at least two minutes before beginning work (the system has a back-up capacitor that must fully discharge). For more information see Chapter 12.


1 Relieve the fuel system pressure (see Chapter 4A).

2 Remove the battery as described in Chapter 5A, then lift out the plastic battery tray.

3 Remove the bonnet as described in Chapter 11.

4 Remove the air cleaner assembly (see Chapter 4A).

5 Raise the vehicle and support it securely on axle stands. Drain the cooling system and engine oil and remove the drivebelts (see Chapter 1).

6 Clearly label, then disconnect, all vacuum lines, coolant and emissions hoses, wiring harness connectors, earth straps and fuel lines. Masking tape and/or a touch up paint applicator work well for marking items (see illustration). Take photos or sketch the locations of components and brackets.

7 Remove the windscreen washer tank and coolant reservoir tank.

8 Remove the cooling fan(s) and radiator (see Chapter 3).

9 Disconnect the heater hoses.

10 Release the residual fuel pressure in the tank by removing the fuel tank cap, then detach the fuel lines connecting the engine to the chassis. Plug or cap all open fittings.

11 Disconnect the accelerator cable, transmission Throttle Valve (TV) linkage and speed control cable, if equipped, from the engine.

12 Refer Chapter 4A and remove the intake and exhaust manifolds.

13 On power steering-equipped vehicles, unbolt the power steering pump. If clearance allows, tie the pump aside without disconnecting the hoses. If necessary, remove the pump (see Chapter 10).

14 On air conditioned models, unbolt the compressor and set it aside. Do not disconnect the refrigerant hoses. Note: Don't let the compressor hang on the hoses.

15 Attach a lifting sling to the engine. Position a hoist and connect the sling to it. Take up the slack until there is slight tension on the hoist.

16 Refer to Chapter 8 and remove the driveshafts.

17 Remove the auxiliary drivebelt(s), coolant pump pulley and crankshaft pulley.

18 On automatic transmission-equipped models, pry out the plastic torque converter dust shield from the lower bellhousing. Remove the torque converter-to-driveplate fasteners (see Chapter 7B) and push the converter back slightly into the bellhousing.

19 Remove the engine-to-transmission bolts and separate the engine from the transmission (see Chapter 7A or 7B). The torque converter should remain in the transmission. Note: If the transmission is to be removed at the same time, the left-side engine mounting should be removed, along with any wires, cables or hoses connected to the transmission. The engine-to-transmission bolts should remain in place at this time.

20 Recheck to be sure nothing except the mountings are still connecting the engine to the vehicle or to the transmission. Disconnect and label anything still remaining.

21 Support the transmission with a trolley jack. Place a block of wood on the jack head to prevent damage to the transmission. Remove the bolts from the engine mountings, leaving those attached to the transmission in place.

A Warning: Do not place any part of your body under the engine/ transmission when its supported only by a hoist or other lifting device.

22 Slowly lift the engine (or engine/ transmission) out of the vehicle (see illustration). It may be necessary to lever the

How Set Cam Timing Toyota 4zz
4.22 Lift the engine out of the vehicle

mountings away from the frame brackets. Note: When removing the engine from a manual transmission-equipped vehicle and the transmission is to remain in the vehicle, you may have to use the jack supporting the transmission to tilt the transmission enough to allow the engine to be angled out of the vehicle.

23 Move the engine away from the vehicle and carefully lower the hoist until the engine can be set on the floor; or remove the flywheel/ driveplate and mount the engine on an engine stand. Note: On automatic transmission-equipped models, mark the front and rear spacer plates (where fitted) and keep them with the driveplate.


24 Check the engine/transmission mountings. If they're worn or damaged, renew them.

25 On manual transmission-equipped models, inspect the clutch components (see Chapter 6) and on automatic models inspect the converter seal and bushing.

26 On automatic transmission-equipped models, apply a dab of grease to the nose of the converter.

27 Carefully guide the transmission into place, following the procedure outlined in Chapter 7A or 7B.

Caution: Do not use the bolts to force the engine and transmission into alignment. They may crack or damage major components.

28 Install the engine-to-transmission bolts and tighten them to the torque listed in the Chapter 7A or 7B Specifications.

29 Attach the hoist to the engine and carefully lower the engine/transmission assembly into the engine compartment. Note: If the engine was removed with the transmission remaining in the car, lower the engine into the car until an assistant can help you line up the dowel pins on the block with the transmission. Some twisting and angling of the engine and/or the transmission will be necessary to secure proper alignment of the two.

30 Install the mounting bolts and tighten them securely.

31 Reinstall the remaining components and fasteners in the reverse order of removal.

32 Add coolant, oil, power steering and transmission fluids as needed (see Chapter 1).

33 Run the engine and check for proper operation and leaks. Shut off the engine and recheck the fluid levels.

5 Engine rebuilding alternatives

The do-it-yourselfer is faced with a number of options when performing an engine overhaul. The decision to renew the engine block, piston/connecting rod assemblies and crankshaft depends on a number of factors, with the number one consideration being the condition of the block. Other considerations are cost, access to machine shop facilities, parts availability, time required to complete the project and the extent of prior mechanical experience on the part of the do-it-yourselfer.

Some of the rebuilding alternatives include:

Individual parts

If the inspection procedures reveal that the engine block and most engine components are in re-usable condition, purchasing individual parts may be the most economical alternative. The block, crankshaft and piston/connecting rod assemblies should all be inspected carefully. Even if the block shows little wear, the cylinder bores should be surface honed.

Short engine

A short engine consists of an engine block with a crankshaft and piston/connecting rod assemblies already installed. All new bearings are incorporated and all clearances will be correct. The existing camshafts, valve train components, cylinder head and external parts can be bolted to the short engine with little or no machine shop work necessary.

Reconditioned engine

A reconditioned engine usually consists of a short engine plus an oil pump, oil pan, cylinder head, valve cover, camshaft and valve train components, timing sprockets and timing belt covers. All components are installed with new bearings, seals and gaskets incorporated throughout. The installation of manifolds and external parts is all that's necessary.

Give careful thought to which alternative is best for you and discuss the situation with local automotive machine shops, auto parts dealers and experienced rebuilders before ordering or purchasing new parts.

6 Engine overhaul -

disassembly sequence

1 It's much easier to disassemble and work on the engine if it's mounted on a portable engine stand. A stand can often be rented quite cheaply from an equipment rental yard. Before the engine is mounted on a stand, the flywheel/driveplate and oil seal retainer should be removed from the engine.

2 If a stand isn't available, it's possible to disassemble the engine with it blocked up on the floor. Be extra careful not to tip or drop the engine when working without a stand.

3 If you're going to obtain a reconditioned engine, all external components must come off first, to be transferred to the new engine, just as they will if you're doing a complete engine overhaul yourself. These include:

Alternator and brackets. Emissions control components. Thermostat and housing cover. Water pump and remaining cooling system components.

EFI components. Intake/exhaust manifolds. Oil filter.

Engine mountings. Clutch and flywheel/driveplate. Engine end plate. Note: When removing the external components from the engine, pay close attention to details that may be helpful or important during installation. Note the installed position of gaskets, seals, spacers, pins, brackets, washers, bolts and other small items.

4 If you're obtaining a short engine, which consists of the engine block, crankshaft, pistons and connecting rods all assembled, then the cylinder head, oil sump and oil pump will have to be removed as well from your engine. See Engine rebuilding alternatives for additional information regarding the different possibilities to be considered.

5 If you're planning a complete overhaul, the engine must be disassembled and the internal components removed in the following order.

Intake and exhaust manifolds.

Cylinder head cover.

Timing belt/chain covers.

Timing belt/chain and sprockets.

Cylinder head.

Oil sump.

Oil pump.

Piston/connecting rod assemblies. Crankshaft oil seal retainer. Crankshaft and main bearings.

7 Cylinder head -

disassembly ^

1 Cylinder head disassembly involves removal of the intake and exhaust valves and related components. It's assumed that the rockers/ followers and camshafts have already been removed (see Part A as needed).

2 Before the valves are removed, arrange to label and store them, along with their related components, so they can be kept separate and reinstalled in the same valve guides they are removed from (see illustration).

3 Compress the springs on the first valve with a spring compressor and remove the collets (see illustration). Carefully release the valve spring compressor and remove the retainer, the spring and the spring seat (if used).

Caution: Be very careful not to nick or otherwise damage the follower bores when compressing the valve springs.

4 Pull the valve out of the head, then remove the oil seal from the guide. If the valve binds in the guide (won't pull through), push it back into the head and deburr the area around the keeper groove with a fine file or whetstone.

5 Repeat the procedure for the remaining valves. Remember to keep all the parts for each valve together so they can be reinstalled in the same locations.

6 Once the valves and related components have been removed and stored in an organised

7.2 A small plastic bag, with an appropriate label, can be used to store the valve components manner, the head should be thoroughly cleaned and inspected. If a complete engine overhaul is being done, finish the engine disassembly procedures before beginning the cylinder head cleaning and inspection process.

8 Cylinder head -

cleaning and inspection

1 Thorough cleaning of the cylinder head and related valve train components, followed by a detailed inspection, will enable you to decide how much valve service work must be done during the engine overhaul. Note: If the engine was severely overheated, the cylinder head is probably warped (see paragraph 12).


2 Scrape all traces of old gasket material and sealing compound off the head gasket, intake manifold and exhaust manifold sealing surfaces. Be very careful not to gouge the cylinder head. Special gasket removal solvents that soften gaskets and make removal much easier are available at automotive accessory/ parts retailers.

3 Remove all built-up scale from the coolant passages.

4 Run a stiff wire brush through the various holes to remove deposits that may have formed in them. If there are heavy rust deposits in the water passages, the bare head should be professionally cleaned.

5 Run an appropriate-size tap into each of the threaded holes to remove corrosion and thread sealant that may be present. If compressed air is available, use it to clear the holes of debris produced by this operation.

Warning: Wear eye protection when using compressed air.

6 Clean the exhaust and intake manifold stud threads with a wire brush.

7 Clean the cylinder head with solvent and dry it thoroughly. Compressed air will speed the drying process and ensure that all holes and recessed areas are clean. Note: Decarbonising chemicals are available and may prove very useful when cleaning cylinder heads and valve

Corolla 4zz Thermostat

7.3 Compress the spring until the collets can be removed with a small magnetic screwdriver or thin-nosed pliers train components. They are very caustic and should be used with caution. Be sure to follow the instructions on the container.

8 Clean the followers with solvent and dry them thoroughly. Compressed air will speed the drying process and can be used to clean out the oil passages. Don't mix them up during the cleaning process; keep them in a box with numbered compartments.

9 Clean all the valve springs, spring seats, collets and retainers with solvent and dry them thoroughly. Work on the components from one valve at a time to avoid mixing up the parts.

10 Scrape off any heavy deposits that may have formed on the valves, then use a motorised wire brush to remove deposits from the valve heads and stems. Again, make sure the valves don't get mixed up.


Note: Be sure to perform all of the following inspection procedures before concluding that machine shop work is required. Make a list of the items that need attention. The inspection procedures for the followers and camshafts can be found in Part A.

Cylinder head

11 Inspect the head very carefully for cracks, evidence of coolant leakage and other damage. If cracks are found, check with an automotive machine workshop concerning repair. If repair isn't possible, a new cylinder head should be obtained.

12 Using a straight-edge and feeler gauge, check the head gasket mating surface for warpage (see illustration). If the warpage

Toyota 3zz Cylinder Head Sub Assy

8.12 Check the cylinder head gasket surface for warpage by trying to slip a feeler gauge under the straight-edge

8.17 Measure the free length of each valve 8.18 Check each valve spring for spring squareness exceeds the limit found in this Chapter's Specifications, it can be resurfaced at an automotive machining workshop.

13 Examine the valve seats in each of the combustion chambers. If they're pitted, cracked or burned, the head will require valve service that's beyond the scope of the home mechanic.

14 If in any doubt as to the condition of the cylinder head, have it inspected by an automotive engine overhaul specialist.


15 Carefully inspect each valve face for uneven wear, deformation, cracks, pits and burned areas. Check the valve stem for scuffing and galling and the neck for cracks. Rotate the valve and check for any obvious indication that it's bent. Look for pits and excessive wear on the end of the stem. The presence of any of these conditions indicates the need for valve service by an automotive machine shop.

16 If in any doubt as to the condition of the valves, have them inspected by an automotive engine overhaul specialist.

Valve components

17 Check each valve spring for wear (on the ends) and pits. Measure the free length and compare it to this Chapter's Specifications (see illustration). Any springs that are shorter than specified have sagged and should not be re-used.

18 Stand each spring on a flat surface and check it for squareness (see illustration). If

10.3 Tap the valve stem seals (arrowed) into place with a deep socket and hammer

any of the springs are distorted or sagged, renew all of them.

19 Check the spring seats and collets for obvious wear and cracks. Any questionable parts should be renewed, as extensive damage will occur if they fail during engine operation.

20 Any damaged or excessively worn parts must be renewed.

21 If the inspection process indicates that the valve components are in generally poor condition and worn beyond the limits specified, which is usually the case in an engine that's being overhauled, reassemble the valves in the cylinder head and refer to Section 9 for valve servicing recommendations.

9 Valves -

servicing ^

1 Because of the complex nature of the job and the special tools and equipment needed, servicing of the valves, the valve seats and the valve guides, commonly known as a valve job, should be done by a professional.

2 The home mechanic can remove and disassemble the head, do the initial cleaning and inspection, then reassemble and deliver them to an automotive engine overhaul specialist for the actual service work. Doing the inspection will enable you to see what condition the head and valve train components are in and will ensure that you know what work and new parts are required when dealing with the overhaul specialist.

10.6 The small valve stem collets are easier to position when coated with grease

3 The engine overhaul specialist will remove the valves and springs, recondition or renew the valves and valve seats, recondition the valve guides, check and renew the valve springs, spring retainers and collets (as necessary), renew the valve seals, reassemble the valve components and make sure the installed spring height is correct. The cylinder head gasket surface will also be resurfaced if it's warped.

4 After the valve job has been performed by a professional, the head will be in like new condition. When the head is returned, be sure to clean it again before installation on the engine to remove any metal particles and abrasive grit that may still be present from the valve service or head resurfacing operations. Use compressed air, if available, to blow out all the oil holes and passages.

10 Cylinder head reassembly

1 Regardless of whether or not the head was sent for reconditioning, make sure it's clean before beginning reassembly. Note that there are several small core plugs in the head. These should be renewed whenever the engine is overhauled or the cylinder head is reconditioned (see Section 13 for renewal procedure).

2 If the head was sent out for valve servicing, the valves and related components will already be in place.

3 Install new seals on each of the valve guides. On Non-VVT-i engines (4E-FE and 4A-FE) the intake seal lip is grey and the exhaust seal lip is black, whilst on VVT-i engines (4ZZ-FE and 3ZZ-FE) the intake seal body is grey and the exhaust seal body is black. Note: Intake and exhaust valves require different seals - DO NOT mix them up. Gently tap each intake valve seal into place until it's seated on the guide (see illustration).

Caution: Don't hammer on the valve seals once they're seated or you may damage them. Don't twist or cock the seals during installation or they won't seat properly on the valve stems.

4 Beginning at one end of the head, lubricate and install the first valve. Apply clean engine oil to the valve stem.

5 Drop the spring seat or shim(s) over the valve guide and set the valve spring and retainer in place.

6 Compress the springs with a valve spring compressor and carefully install the collets in the upper groove, then slowly release the compressor and make sure the collets seat properly. Apply a small dab of grease to each collet to hold it in place if necessary (see illustration).

7 Repeat the procedure for the remaining valves. Be sure to return the components to their original locations - don't mix them up.

Connecting Rod Corolla 2007

11 Pistons/connecting rods

- removal

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