Toyota Celica, Corolla, ECHO & MR2 1999-05

Cylinder Head

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There are two basic types of cylinder heads used on today's automobiles: the Overhead Valve (OHV) and the Overhead Camshaft (OHC). The latter can also be broken down into two subgroups: the Single Overhead Camshaft (SOHC) and the Dual Overhead Camshaft (DOHC). Generally, if there is only a single camshaft on a head, it is just referred to as an OHC head. Also, an engine with an OHV cylinder head is also known as a pushrod engine.

Most cylinder heads these days are made of an aluminum alloy due to its light weight, durability and heat transfer qualities. However, cast iron was the material of choice in the past, and is still used on many vehicles today. Whether made from aluminum or iron, all cylinder heads have valves and seats. Some use two valves per cylinder, while the more hi-tech engines will utilize a multi-valve configuration using 3, 4 and even 5 valves per cylinder. When the valve contacts the seat, it does so on precision machined surfaces, which seals the combustion chamber. All cylinder heads have a valve guide for each valve. The guide centers the valve to the seat and allows it to move up and down within it. The clearance between the valve and guide can be critical. Too much clearance and the engine may consume oil, lose vacuum and/or damage the seat. Too little, and the valve can stick in the guide causing the engine to run poorly if at all, and possibly causing severe damage. The last component all cylinder heads have are valve springs. The spring holds the valve against its seat. It also returns the valve to this position when the valve has been opened by the valve train or camshaft. The spring is fastened to the valve by a retainer and valve locks (sometimes called keepers). Aluminum heads will also have a valve spring shim to keep the spring from wearing away the aluminum.

An ideal method of rebuilding the cylinder head would involve replacing all of the valves, guides, seats, springs, etc. with new ones. However, depending on how the engine was maintained, often this is not necessary. A major cause of valve, guide and seat wear is an improperly tuned engine. An engine that is running too rich, will often wash the lubricating oil out of the guide with gasoline, causing it to wear rapidly. Conversely, an engine which is running too lean will place higher combustion temperatures on the valves and seats allowing them to wear or even burn. Springs fall victim to the driving habits of the individual. A driver who often runs the engine rpm to the redline will wear out or break the springs faster then one that stays well below it. Unfortunately, mileage takes it toll on all of the parts. Generally, the valves, guides, springs and seats in a cylinder head can be machined and re-used, saving you money. However, if a valve is burnt, it may be wise to replace all of the valves, since they were all operating in the same environment. The same goes for any other component on the cylinder head. Think of it as an insurance policy against future problems related to that component.

Unfortunately, the only way to find out which components need replacing, is to disassemble and carefully check each piece. After the cylinder head(s) are disassembled, thoroughly clean all of the components.

Cylinder Head Overhaul



Assembly

The first step for any assembly job is to have a clean area in which to work. Next, thoroughly clean all of the parts and components that are to be assembled. Finally, place all of the components onto a suitable work space and, if necessary, arrange the parts to their respective positions.

Cup Type Camshaft Followers

To install the springs, retainers and valve locks on heads which have these components recessed into the camshaft follower's bore, you will need a small screwdriver-type tool, some clean white grease and a lot of patience. You will also need the C-clamp style spring compressor and the OHC tool used to disassemble the head.

  1. Lightly lubricate the valve stems and insert all of the valves into the cylinder head. If possible, maintain their original locations.
  2.  
  3. If equipped, install any valve spring shims which were removed.
  4.  
  5. If equipped, install the new valve seals, keeping the following in mind:

    If the valve seal presses over the guide, lightly lubricate the outer guide surfaces.
     
    If the seal is an O-ring type, it is installed just after compressing the spring but before the valve locks.
     

  6.  
  7. Place the valve spring and retainer over the stem.
  8.  
  9. Position the spring compressor and the OHC tool, then compress the spring.
  10.  
  11. Using a small screwdriver as a spatula, fill the valve stem side of the lock with white grease. Use the excess grease on the screwdriver to fasten the lock to the driver.
  12.  
  13. Carefully install the valve lock, which is stuck to the end of the screwdriver, to the valve stem then press on it with the screwdriver until the grease squeezes out. The valve lock should now be stuck to the stem.
  14.  
  15. Repeat Steps 6 and 7 for the remaining valve lock.
  16.  
  17. Relieve the spring pressure slowly and insure that neither valve lock becomes dislodged by the retainer.
  18.  
  19. Remove the spring compressor tool.
  20.  
  21. Repeat Steps 2 through 10 until all of the springs have been installed.
  22.  
  23. Install the followers, camshaft(s) and any other components that were removed for disassembly.
  24.  



Click image to see an enlarged view

Fig. Once assembled, check the valve clearance and correct as needed

Rocker Arm Type Camshaft Followers
  1. Lightly lubricate the valve stems and insert all of the valves into the cylinder head. If possible, maintain their original locations.
  2.  
  3. If equipped, install any valve spring shims which were removed.
  4.  
  5. If equipped, install the new valve seals, keeping the following in mind:

    If the valve seal presses over the guide, lightly lubricate the outer guide surfaces.
     
    If the seal is an O-ring type, it is installed just after compressing the spring but before the valve locks.
     

  6.  
  7. Place the valve spring and retainer over the stem.
  8.  
  9. Position the spring compressor tool and compress the spring.
  10.  
  11. Assemble the valve locks to the stem.
  12.  
  13. Relieve the spring pressure slowly and insure that neither valve lock becomes dislodged by the retainer.
  14.  
  15. Remove the spring compressor tool.
  16.  
  17. Repeat Steps 2 through 8 until all of the springs have been installed.
  18.  
  19. Install the camshaft(s), rockers, shafts and any other components that were removed for disassembly.
  20.  

Disassembly

Whether it is a single or dual overhead camshaft cylinder head, the disassembly procedure is relatively unchanged. One aspect to pay attention to is careful labeling of the parts on the dual camshaft cylinder head. There will be an intake camshaft and followers as well as an exhaust camshaft and followers and they must be labeled as such. In some cases, the components are identical and could easily be installed incorrectly. DO NOT MIX THEM UP! Determining which is which is very simple; the intake camshaft and components are on the same side of the head as was the intake manifold. Conversely, the exhaust camshaft and components are on the same side of the head as was the exhaust manifold.



Click image to see an enlarged view

Fig. Exploded view of a valve, seal, spring, retainer and locks from an OHC cylinder head



Click image to see an enlarged view

Fig. Example of a multi-valve cylinder head. Note how it has 2 intake and 2 exhaust valve ports

Cup Type Camshaft Followers

Most cylinder heads with cup type camshaft followers will have the valve spring, retainer and locks recessed within the follower's bore. You will need a C-clamp style valve spring compressor tool, an OHC spring removal tool (or equivalent) and a small magnet to disassemble the head.



Click image to see an enlarged view

Fig. C-clamp type spring compressor and an OHC spring removal tool (center) for cup type followers

  1. If not already removed, remove the camshaft(s) and/or followers. Mark their positions for assembly.
  2.  



Click image to see an enlarged view

Fig. Most cup type follower cylinder heads retain the camshaft using bolt-on bearing caps

  1. Position the cylinder head to allow use of a C-clamp style valve spring compressor tool.
  2.  

It is preferred to position the cylinder head gasket surface facing you with the valve springs facing the opposite direction and the head laying horizontal.



Click image to see an enlarged view

Fig. Position the OHC spring tool in the follower bore, then compress the spring with a C-clamp type tool

  1. With the OHC spring removal adapter tool positioned inside of the follower bore, compress the valve spring using the C-clamp style valve spring compressor.
  2.  
  3. Remove the valve locks. A small magnetic tool or screwdriver will aid in removal.
  4.  
  5. Release the compressor tool and remove the spring assembly.
  6.  
  7. Withdraw the valve from the cylinder head.
  8.  
  9. If equipped, remove the valve seal.
  10.  

Special valve seal removal tools are available. Regular or needle nose type pliers, if used with care, will work just as well. If using ordinary pliers, be sure NOT to damage the follower bore. The follower and its bore are machined to close tolerances and any damage to the bore will effect this relationship.

  1. If equipped, remove the valve spring shim. A small magnetic tool or screwdriver will aid in removal.
  2.  
  3. Repeat Steps 3 through 8 until all of the valves have been removed.
  4.  

Rocker Arm Type Camshaft Followers

Most cylinder heads with rocker arm-type camshaft followers are easily disassembled using a standard valve spring compressor. However, certain models may not have enough open space around the spring for the standard tool and may require you to use a C-clamp style compressor tool instead.



Click image to see an enlarged view

Fig. Example of the shaft mounted rocker arms on some OHC heads



Click image to see an enlarged view

Fig. Another example of the rocker arm type OHC head. This model uses a follower under the camshaft

  1. If not already removed, remove the rocker arms and/or shafts and the camshaft. If applicable, also remove the hydraulic lash adjusters. Mark their positions for assembly.
  2.  



Click image to see an enlarged view

Fig. Before the camshaft can be removed, all of the followers must first be removed ...



Click image to see an enlarged view

Fig. ... then the camshaft can be removed by sliding it out (shown), or unbolting a bearing cap (not shown)

  1. Position the cylinder head to allow access to the valve spring.
  2.  
  3. Use a valve spring compressor tool to relieve the spring tension from the retainer.
  4.  



Click image to see an enlarged view

Fig. Compress the valve spring ...

Due to engine varnish, the retainer may stick to the valve locks. A gentle tap with a hammer may help to break it loose.



Click image to see an enlarged view

Fig. ... then remove the valve locks from the valve stem and spring retainer

  1. Remove the valve locks from the valve tip and/or retainer. A small magnet may help in removing the small locks.
  2.  
  3. Lift the valve spring, tool and all, off of the valve stem.
  4.  



Click image to see an enlarged view

Fig. Remove the valve spring and retainer from the cylinder head

  1. If equipped, remove the valve seal. If the seal is difficult to remove with the valve in place, try removing the valve first, then the seal. Follow the steps below for valve removal.
  2.  



Click image to see an enlarged view

Fig. Remove the valve seal from the guide. Some gentle prying or pliers may help to remove stubborn ones

  1. Position the head to allow access for withdrawing the valve.
  2.  

Cylinder heads that have seen a lot of miles and/or abuse may have mushroomed the valve lock grove and/or tip, causing difficulty in removal of the valve. If this has happened, use a metal file to carefully remove the high spots around the lock grooves and/or tip. Only file it enough to allow removal.

  1. Remove the valve from the cylinder head.
  2.  



Click image to see an enlarged view

Fig. All aluminum and some cast iron heads will have these valve spring shims. Remove all of them as well

  1. If equipped, remove the valve spring shim. A small magnetic tool or screwdriver will aid in removal.
  2.  
  3. Repeat Steps 3 though 9 until all of the valves have been removed.
  4.  

Inspection

Now that all of the cylinder head components are clean, it's time to inspect them for wear and/or damage. To accurately inspect them, you will need some specialized tools:



A 0-1 in. micrometer for the valves
 
A dial indicator or inside diameter gauge for the valve guides
 
A spring pressure test gauge
 

If you do NOT have access to the proper tools, you may want to bring the components to a shop that does.

There are several things to check on the cylinder head: valve guides, seats, cylinder head surface flatness, cracks and physical damage.

Cracks And Physical Damage

Generally, cracks are limited to the combustion chamber, however, it is not uncommon for the head to crack in a spark plug hole, port, outside of the head or in the valve spring/rocker arm area. The first area to inspect is always the hottest: the exhaust seat/port area.

A visual inspection should be performed, but just because you don't see a crack does not mean it is not there. Some more reliable methods for inspecting for cracks include Magnaflux®, a magnetic process or Zyglo®, a dye penetrant. Magnaflux®is used only on ferrous metal (cast iron) heads. Zyglo®uses a spray on fluorescent mixture along with a black light to reveal the cracks. It is strongly recommended to have your cylinder head checked professionally for cracks, especially if the engine was known to have overheated and/or leaked or consumed coolant. Contact a local shop for availability and pricing of these services.

Physical damage is usually very evident. For example, a broken mounting ear from dropping the head or a bent or broken stud and/or bolt. All of these defects should be fixed or, if unrepairable, the head should be replaced.

Cylinder Head Flatness

After you have cleaned the gasket surface of the cylinder head of any old gasket material, check the head for flatness.



Click image to see an enlarged view

Fig. Check the head for flatness across the center of the head surface using a straightedge and feeler gauge



Click image to see an enlarged view

Fig. Checks should also be made along both diagonals of the head surface

Place a straightedge across the gasket surface. Using feeler gauges, determine the clearance at the center of the straightedge and across the cylinder head at several points. Check along the centerline and diagonally on the head surface. If the warpage exceeds 0.003 in. (0.076mm) within a 6.0 in. (15.2cm) span, or 0.006 in. (0.152mm) over the total length of the head, the cylinder head must be resurfaced. After resurfacing the heads of a V-type engine, the intake manifold flange surface should be checked, and if necessary, milled proportionally to allow for the change in its mounting position.

Certain cracks can be repaired in both cast iron and aluminum heads. For cast iron, a tapered threaded insert is installed along the length of the crack. Aluminum can also use the tapered inserts, however welding is the preferred method. Some physical damage can be repaired through brazing or welding. Contact a machine shop to get expert advice for your particular dilemma.

Valve Seats

A visual inspection of the valve seats should show a slightly worn and pitted surface where the valve face contacts the seat. Inspect the seat carefully for severe pitting or cracks. Also, a seat that is badly worn will be recessed into the cylinder head. A severely worn or recessed seat may need to be replaced. All cracked seats must be replaced. A seat concentricity gauge, if available, should be used to check the seat run-out. If run-out exceeds specifications the seat must be machined (if no specification is given use 0.002 in. or 0.051mm).

Refinishing & Repairing

Many of the procedures given for refinishing and repairing the cylinder head components must be performed by a machine shop. Certain steps, if the inspected part is not worn, can be performed yourself inexpensively. However, you spent a lot of time and effort so far, why risk trying to save a couple bucks if you might have to do it all over again-

Cylinder Head

Most refinishing procedures dealing with the cylinder head must be performed by a machine shop. Read the sections below and review your inspection data to determine whether or not machining is necessary.

Cylinder Head Surface

If the cylinder head is warped, it must be machined flat. If the warpage is extremely severe, the head may need to be replaced. In some instances, it may be possible to straighten a warped head enough to allow machining. In either case, contact a professional machine shop for service.

Any OHC cylinder head that shows excessive warpage should have the camshaft bearing journals align bored after the cylinder head has been resurfaced.


WARNING
Failure to align bore the camshaft bearing journals could result in severe engine damage including but not limited to: valve and piston damage, connecting rod damage, camshaft and/or crankshaft breakage.

Valve Guides

If any machining or replacements are made to the valve guides, the seats must be machined.

Unless the valve guides need machining or replacing, the only service to perform is to thoroughly clean them of any dirt or oil residue.

There are only two types of valve guides used on automobile engines: the replaceable-type (all aluminum heads) and the cast-in integral-type (most cast iron heads). There are four recommended methods for repairing worn guides.



Knurling
 
Inserts
 
Reaming oversize
 
Replacing
 

Knurling is a process in which metal is displaced and raised, thereby reducing clearance, giving a true center, and providing oil control. It is the least expensive way of repairing the valve guides. However, it is not necessarily the best, and in some cases, a knurled valve guide will not stand up for more than a short time. It requires a special knurlizer and precision reaming tools to obtain proper clearances. It would not be cost effective to purchase these tools, unless you plan on rebuilding several of the same cylinder head.

Installing a guide insert involves machining the guide to accept a bronze insert. One style is the coil-type which is installed into a threaded guide. Another is the thin-walled insert where the guide is reamed oversize to accept a split-sleeve insert. After the insert is installed, a special tool is then run through the guide to expand the insert, locking it to the guide. The insert is then reamed to the standard size for proper valve clearance.

Reaming for oversize valves restores normal clearances and provides a true valve seat. Most cast-in type guides can be reamed to accept an valve with an oversize stem. The cost factor for this can become quite high as you will need to purchase the reamer and new, oversize stem valves for all guides which were reamed. Oversizes are generally 0.003 to 0.030 in. (0.076 to 0.762mm), with 0.015 in. (0.381mm) being the most common.

To replace cast-in type valve guides, they must be drilled out, then reamed to accept replacement guides. This must be done on a fixture which will allow centering and leveling off of the original valve seat or guide, otherwise a serious guide-to-seat misalignment may occur making it impossible to properly machine the seat.

Replaceable-type guides are pressed into the cylinder head. A hammer and a stepped drift or punch may be used to install and remove the guides. Before removing the guides, measure the protrusion on the spring side of the head and record it for installation. Use the stepped drift to hammer out the old guide from the combustion chamber side of the head. When installing, determine whether or not the guide also seals a water jacket in the head, and if it does, use the recommended sealing agent. If there is no water jacket, grease the valve guide and its bore. Use the stepped drift, and hammer the new guide into the cylinder head from the spring side of the cylinder head. A stack of washers the same thickness as the measured protrusion may help the installation process.

Valve Seats

Before any valve seat machining can be performed, the guides must be within factory recommended specifications.

If any machining or replacements were made to the valve guides, the seats must be machined.

If the seats are in good condition, the valves can be lapped to the seats, and the cylinder head assembled. See the valves section for instructions on lapping.

If the valve seats are worn, cracked or damaged, they must be serviced by a machine shop. The valve seat must be perfectly centered to the valve guide, which requires very accurate machining.

Springs, Retainers & Valve Locks

There is no repair or refinishing possible with the springs, retainers and valve locks. If they are found to be worn or defective, they must be replaced with new (or known good) parts.

Valves

Any valves that were not replaced should be refaced and the tips ground flat. Unless you have access to a valve grinding machine, this should be done by a machine shop. If the valves are in extremely good condition, as well as the valve seats and guides, they may be lapped in without performing machine work.

It is a recommended practice to lap the valves even after machine work has been performed and/or new valves have been purchased. This insures a positive seal between the valve and seat.

Lapping The Valves

Before lapping the valves to the seats, read the rest of the cylinder head section to insure that any related parts are in acceptable enough condition to continue.

Before any valve seat machining and/or lapping can be performed, the guides must be within factory recommended specifications.

  1. Invert the cylinder head.
  2.  
  3. Lightly lubricate the valve stems and insert them into the cylinder head in their numbered order.
  4.  
  5. Raise the valve from the seat and apply a small amount of fine lapping compound to the seat.
  6.  
  7. Moisten the suction head of a hand-lapping tool and attach it to the head of the valve.
  8.  
  9. Rotate the tool between the palms of both hands, changing the position of the valve on the valve seat and lifting the tool often to prevent grooving.
  10.  
  11. Lap the valve until a smooth, polished circle is evident on the valve and seat.
  12.  
  13. Remove the tool and the valve. Wipe away all traces of the grinding compound and store the valve to maintain its lapped location.
  14.  


WARNING
Do NOT get the valves out of order after they have been lapped. They must be put back with the same valve seat with which they were lapped.

Removal & Installation



1NZ-FE Engines
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Drain the cooling system.
  4.  
  5. Remove or disconnect the following:

    Negative battery cable
     
    Water filler
     
    Outer front cowl top panel
     
    Alternator
     
    Air cleaner
     
    Accelerator cable
     
    Center exhaust pipe
     
    Exhaust manifold support
     
    Exhaust manifold
     
    Ignition coil
     
    Spark plugs
     
    PCV hoses
     
    Throttle body
     
    Engine wiring harness at the head
     
    Intake manifold
     
    Camshaft position sensor
     
    ECT sensor
     
    Oil control valve
     
    PCV valve
     
    Oil filer cap
     
    Cylinder head cover
     
    Fuel injectors
     
    Timing chain cover
     
    Camshaft sprockets and valve timing control assembly
     
    Camshafts
     
    Cylinder head. Remove the bolts in a circular pattern, in several stages, starting from the ends and working toward the center
     

  6.  

To install:

Click image to see an enlarged view

Fig. Cylinder head bolt tightening sequence-1NZ-FE engine

  1. Install or connect the following:

    Cylinder head, using a new gasket. Make sure to properly orient the gasket based on the instructions printing on the gasket.
     

  2.  
  3. Torque the cylinder head bolts, in sequence, in 3 steps:
    1. Step 1: 22 ft. lbs. (29 Nm).
    2.  
    3. Step 2: Plus a 90 degree turn.
    4.  
    5. Step 3: Plus a 90 degree turn.
    6.  

  4.  
  5. Install or connect the following:

    Water bypass pipe. Torque the bolt to 80 inch lbs. (9 Nm).
     
    Camshafts
     

  6.  
  7. Camshaft bearing caps in 2 stages:
    1. Step: 10 ft. lbs. (13 Nm).
    2.  
    3. Step 2: 17 ft. lbs. (23 Nm).
    4.  

  8.  
  9. Install or connect the following:

    Sprockets and valve timing controller assembly, aligning the knock pin and hole. Torque the bolts to 47 ft. lbs. (64 Nm).
     
    Check and adjust the valves
     
    Cylinder head cover
     
    Oil filler cap
     
    PCV valve
     
    ECT sensor
     
    Camshaft position sensor
     
    Timing chain cover
     
    Intake manifold
     
    Engine wiring harness
     
    Throttle body
     
    PCV hoses
     
    Spark plugs
     
    Ignition coils
     
    Exhaust manifold
     
    Exhaust manifold support. Torque the bolts to 27 ft. lbs. (37 Nm).
     
    Front exhaust pipe. Torque the nuts to 46 ft. lbs. (62 Nm).
     
    Accelerator cable
     
    Air cleaner
     
    Alternator
     
    Water filler
     
    Negative battery cable
     

  10.  
  11. Fill the cooling system to the proper level.
  12.  
  13. Start the vehicle, check for leaks and repair if necessary.
  14.  

1zz-FE Engines
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Drain the cooling system.
  4.  
  5. Remove or disconnect the following:

    Battery
     
    ECU box
     
    Coolant reservoir
     
    Air cleaner assembly
     
    Accelerator cable
     
    Alternator
     
    Exhaust pipe
     
    Exhaust manifold
     
    Coils
     
    Spark plugs
     
    PCV hoses
     
    Throttle body
     
    Injectors
     
    Wiring harness
     
    Intake manifold
     
    Camshaft position sensor
     
    ECT sensor
     
    PCV valve
     
    Oil filler cap
     
    Camshaft sprockets
     
    Camshafts
     
    Hoses
     
    Cylinder head bolts in sequence. To prevent damage to the cylinder head, loosen each bolt about 1 / 4 of a turn during each pass until the bolts are loose.
     
    Cylinder head
     

  6.  

To install:

Click image to see an enlarged view

Fig. Cylinder head component removal-1ZZ-FE engine



Click image to see an enlarged view

Fig. Cylinder head bolt tightening sequence-1ZZ-FE engine

  1. Clean and degrease the surface of the cylinder head and engine block.
  2.  
  3. Install or connect the following:

    New gasket on the engine block with the Lod No. stamp facing up.
     
    Cylinder head
     
    Apply a light coat of oil to cylinder head bolt threads and tighten in sequence. Replace any bolt that appears deformed. Bolts: 36 ft. lbs. (49 Nm).
     
    Tighten each bolt in sequence an additional 90 degree turn.
     
    Camshafts
     
    Sprockets
     
    Oil filler cap
     
    PCV valve
     
    ECT sensor
     
    Intake manifold
     
    Wiring harness
     
    Exhaust manifold
     
    Exhaust pipe
     
    Alternator
     
    accelerator cable
     
    Air cleaner
     
    ECM box
     
    Battery
     

  4.  
  5. Fill the cooling system to the proper level.
  6.  
  7. Start the vehicle, check for leaks and repair if necessary.

    Click image to see an enlarged view

    Fig. Exploded view of engine accessories and right-hand engine under cover-1.8L (1ZZ-FE) engine



    Click image to see an enlarged view

    Fig. View of engine intake, exhaust, ignition, and fuel system location-1.8L (1ZZ-FE) engine



    Click image to see an enlarged view

    Fig. Illustration of disassembled cylinder head assembly-1.8L (1ZZ-FE) engine



    Click image to see an enlarged view

    Fig. Position the head gasket correctly on the cylinder head-1.8L (1ZZ-FE) engine

  8.  

2zz-Ge & 2zz-FE Engines
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Drain the cooling system.
  4.  
  5. Remove or disconnect the following:

    Battery
     
    ECU box
     
    Coolant reservoir
     
    Air cleaner assembly
     
    Accelerator cable
     
    Alternator
     
    Exhaust pipe
     
    Exhaust manifold
     
    Coils
     
    Spark plugs
     
    PCV hoses
     
    Throttle body
     
    Injectors
     
    Wiring harness
     
    Intake manifold
     
    Camshaft position sensor
     
    ECT sensor
     
    PCV valve
     
    Oil filler cap
     
    Camshaft sprockets
     
    Camshafts
     
    Hoses
     
    Cylinder head bolts in sequence. To prevent damage to the cylinder head, loosen each bolt about 1 / 4 of a turn during each pass until the bolts are loose.
     
    Cylinder head
     

  6.  

To install:

Click image to see an enlarged view

Fig. Cylinder head component exploded view-2ZZ-GE engine

  1. Clean and degrease the surface of the cylinder head and engine block.
  2.  
  3. Install or connect the following:

    New gasket on the engine block with the Lod No. stamp facing up.
     
    Cylinder head
     
    Apply a light coat of oil to cylinder head bolt threads and tighten in sequence. Replace any bolt that appears deformed. Bolts: 26 ft. lbs. (49 Nm).
     
    Torque each bolt in sequence an additional 180 degree turn.
     
    Camshafts
     
    Sprockets
     
    Oil filler cap
     
    PCV valve
     
    ECT sensor
     
    Intake manifold
     
    Wiring harness
     
    Exhaust manifold
     
    Exhaust pipe
     
    Alternator
     
    accelerator cable
     
    Air cleaner
     
    ECM box
     
    Battery
     

  4.  
  5. Fill the cooling system to the proper level.
  6.  
  7. Start the vehicle, check for leaks and repair if necessary.
  8.  

 
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