Ram B1500, B2500, B3500, 1999-2003

Cylinder Head 1

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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.

All engines covered are OHV with the exception of the SOHC 4.7L V-8.

Some cylinder heads these days are made of an aluminum alloy due to its lightweight, durability and heat transfer qualities. However, cast iron was the material of choice in the past, and is still used on most vehicles today.

All engines covered have iron heads with the exception of the aluminum head 4.7L V-8.

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.

All the engines covered have two valves per cylinder with the exception of the 24-valve, 6-cylinder diesel.

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).

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 that 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.

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 workspace and, if necessary, arrange the parts to their respective positions.

4.7L Engine
  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 that 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 ensure 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.  

OHV Engines
  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 that 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 ensure 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.  

Cleaning & Inspecting

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: bolts, valve guides, seats, cylinder head surface flatness, cracks and physical damage.

Cylinder Head Bolts

Using new head bolts after a rebuild is good practice. Engines in heavy-duty applications or operating under severe service conditions should always be given new head bolts.

No head bolts should be used (removed/installed) more than twice. Mark reused head bolts with a dab of paint so the next rebuilder will know to use new parts.

Check head bolts for thread damage, a stretched condition, or "necking".



Click image to see an enlarged view

Fig. Check head bolts for rounded heads (1, 4), necking (2), or thread damage (3)

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).

Checking The Cylinder Head For Warpage (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.

Cracks & 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, you may see 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.

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.

Disassembly
4.7L Heads

Be sure to label the position of all components before disassembly.

Although this is an OHC cylinder head, it can be disassembled using a standard valve spring compressor. A C-clamp style compressor tool is recommended.



Click image to see an enlarged view

Fig. A C-clamp type spring compressor is easier to use on OHC heads



Click image to see an enlarged view

Fig. The 4.7L OHC head uses rocker arms under the camshafts

  1. If not already removed, remove the rocker arms and the camshaft. 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 . . .



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Fig. . . . then the camshaft can be removed by unbolting a bearing cap



Click image to see an enlarged view

Fig. Bearing cap removed

  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.  


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

  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.  


NOTE
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. Most 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.  

Ohv Heads

Before disassembling the cylinder head, you may want to fabricate some containers to hold the various parts, as some of them can be quite small (such as keepers) and easily lost. Also keeping yourself and the components organized will aid in assembly and reduce confusion. Where possible, try to maintain a components original location; this is especially important if there is not going to be any machine work performed on the components.

  1. If you haven't already removed the rocker arms completely do so now.
  2.  
  3. Position the head so that the springs are easily accessed.
  4.  



Click image to see an enlarged view

Fig. When removing an OHV valve spring, use a compressor tool to relieve the tension from the retainer

  1. Use a valve spring compressor tool, and relieve spring tension from the retainer.
  2.  


NOTE
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. A small magnet will help in removal of the valve locks



Click image to see an enlarged view

Fig. Be careful not to lose the small valve locks (keepers)

  1. Remove the valve locks from the valve tip and/or retainer. A small magnet may help in removing the 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 seal from the valve stem-O-ring type seal shown



Click image to see an enlarged view

Fig. Removing an umbrella/positive type seal

  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. Invert the cylinder head and withdraw the valve from the valve guide bore

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


NOTE
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.  
  3. If equipped, remove the valve spring shim. A small magnetic tool or screwdriver will aid in removal.
  4.  
  5. Repeat Steps 3 though 9 until all of the valves have been removed.
  6.  



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

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.


NOTE
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

NOTE
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 knurling 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 that 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 a valve with an oversize stem. The cost factor for this can become quite high, since you will need to purchase the reamer and new, oversize stemmed valves for all guides that 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

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


NOTE
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 ensures a positive seal between the valve and seat.

Lapping The Valves

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


NOTE
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 allow the valves to get 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



  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Drain the cooling system.
  4.  
  5. Drain the engine oil.
  6.  
  7. Remove or disconnect the following:
    NOTE
    Keep all valvetrain components in order for assembly.


    NOTE
    If the cylinder head is hot, gradually loosen the cylinder head bolts using the TIGHTENING sequence. If the engine is cold, then the loosening sequence for the head bolts is not important.


    NOTE
    The cylinder head bolts are different sizes. Note their locations for assembly.



    Negative battery cables
     
    Radiator hoses
     
    Heater hoses
     
    Drive belt
     
    Turbocharger
     
    Exhaust Gas Recirculation (EGR) tube
     
    Exhaust manifold
     
    Accelerator pedal position sensor
     
    Fuel lines and injector nozzles
     
    Valve cover
     



    Rocker levers and pedestal assemblies
     
    Pushrods
     
    Fuel filter and water separator assembly
     



    Cylinder head bolts
     
    Cylinder head
     

  8.  

To install:


NOTE
Check the cylinder head bolt length. If length exceeds 5.2 inches (132.1 mm), the bolt must be replaced.

  1. Install or connect the following:

    Cylinder head
     
    Pushrods
     
    Rocker levers and pedestal assemblies

    Click image to see an enlarged view

    Fig. Cylinder head torque sequence-5.9L diesel engine

     

  2.  
  3. Install the cylinder head bolts and tighten them in sequence as follows:
    1. Step 1: 59 ft. lbs. (80 Nm).
    2.  
    3. Step 2: 77 ft. lbs. (104 Nm).
    4.  
    5. Step 3: Retighten to 77 ft. lbs. (80 Nm).
    6.  
    7. Step 4: Tighten an additional 90 degrees
    8.  

  4.  
  5. Install or connect the following:

    Fuel filter and water separator assembly
     
    Valve cover
     
    Fuel lines and injector nozzles
     
    Accelerator pedal position sensor
     
    Exhaust manifold
     
    EGR tube
     
    Turbocharger
     
    Drive belt
     
    Heater hoses
     
    Radiator hoses
     
    Negative battery cables
     

  6.  
  7. Fill the crankcase to the correct level.
  8.  
  9. Fill the cooling system.
  10.  
  11. Start the engine and check for leaks.
  12.  


WARNING
The engine must be cold before attempting to remove the cylinder head. Loosening head bolts on a hot engine may cause component damage.

Read the procedures before starting to get a thorough understanding of the tools and equipment needed. Many cylinder head components are precision-machined pieces that need to be cleaned and carefully inspected before installation. Refer to "Engine Reconditioning" for this information.

3.7L Engine
Left Side
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Drain the cooling system.
  4.  
  5. Properly relieve the fuel system pressure.
  6.  
  7. Remove or disconnect the following:

    Negative battery cable
     
    Exhaust Y-pipe
     
    Intake manifold
     
    Brake booster and master cylinder
     
    Cylinder head cover
     
    Engine cooling fan and shroud
     
    Accessory drive belt
     
    Power steering pump
     

  8.  
  9. Rotate the crankshaft so that the crankshaft timing mark aligns with the Top Dead Center (TDC) mark on the front cover, and the V6 marks on the camshaft sprockets are at 12 o-clock as shown.

    Crankshaft damper
     
    Front cover

    Click image to see an enlarged view

    Fig. Camshaft sprocket timing marks-3.7L

     

  10.  
  11. Lock the secondary timing chain to the idler sprocket with Timing Chain Locking tool 8429.

    Click image to see an enlarged view

    Fig. Camshaft locking tool-3.7L

  12.  
  13. Matchmark the secondary timing chain one link on each side of the V6 mark to the camshaft sprocket.
    NOTE
    The cylinder head is retained by twelve bolts. Four of the bolts are smaller and are at the front of the head.



    Left secondary timing chain tensioner
     
    Cylinder head access plug
     
    Secondary timing chain guide
     
    Camshaft sprocket
     
    Cylinder head
     

  14.  

To install:

Click image to see an enlarged view

Fig. Examine the head bolts for signs of stretching-3.7L engine

  1. Check the cylinder head bolts for signs of stretching and replace as necessary.
  2.  
  3. Lubricate the threads of the 11mm bolts with clean engine oil.
  4.  
  5. Coat the threads of the 8mm bolts with Mopar® Lock and Seal Adhesive.
  6.  
  7. Install the cylinder heads. Use new gaskets and tighten the bolts, in sequence, as follows:
    1. Step 1: Bolts 1-8 to 20 ft. lbs. (27 Nm)
    2.  
    3. Step 2: Bolts 1-10 verify torque without loosening
    4.  
    5. Step 3: Bolts 9-12 to 10 ft. lbs. (14 Nm)
    6.  
    7. Step 4: Bolts 1-8 plus 1 / 4 (90 degree) turn
    8.  
    9. Step 5: Bolts 9-12 to 19 ft. lbs. (26 Nm)

      Click image to see an enlarged view

      Fig. Cylinder head bolt torque sequence-3.7L

    10.  

  8.  
  9. Install or connect the following:

    Camshaft sprocket. Align the secondary chain matchmarks and tighten the bolt to 90 ft. lbs. (122 Nm).
     
    Secondary timing chain guide
     
    Cylinder head access plug
     
    Secondary timing chain tensioner. Refer to the timing chain procedure in this section.
     

  10.  
  11. Remove the Timing Chain Locking tool.
  12.  
  13. Install or connect the following:

    Front cover
     
    Crankshaft damper. Torque the bolt to 130 ft. lbs. (175 Nm).
     
    Power steering pump
     
    Accessory drive belt
     
    Engine cooling fan and shroud
     
    Cover
     
    Intake manifold
     
    Exhaust Y-pipe
     
    Negative battery cable
     

  14.  
  15. Fill and bleed the cooling system.
  16.  
  17. Start the engine, check for leaks and repair if necessary.
  18.  

Right Side
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Drain the cooling system.
  4.  
  5. Properly relieve the fuel system pressure.
  6.  
  7. Remove or disconnect the following:

    Negative battery cable
     
    Exhaust Y-pipe
     
    Intake manifold
     
    Valve cover
     
    Engine cooling fan and shroud
     
    Accessory drive belt
     
    Oil fill housing
     
    Power steering pump
     

  8.  
  9. Rotate the crankshaft so that the crankshaft timing mark aligns with the Top Dead Center (TDC) mark on the front cover, and the V6 marks on the camshaft sprockets are at 12 o-clock as shown.

    Click image to see an enlarged view

    Fig. Crankshaft timing marks-3.7L engine



    Click image to see an enlarged view

    Fig. Camshaft positioning-3.7L engine

  10.  
  11. Remove or disconnect the following:

    Crankshaft damper
     
    Front cover
     

  12.  
  13. Lock the secondary timing chains to the idler sprocket with Timing Chain Locking tool 8429.
  14.  
  15. Matchmark the secondary timing chains to the camshaft sprockets.
  16.  
  17. Remove or disconnect the following:
    NOTE
    Each cylinder head is retained by 8 11mm bolts and four 8mm bolts.



    Secondary timing chain tensioners
     
    Cylinder head access plugs
     
    Secondary timing chain guides
     
    Camshaft sprockets
     
    Cylinder heads
     

  18.  

To install:

  1. Check the cylinder head bolts for signs of stretching and replace as necessary.
  2.  
  3. Lubricate the threads of the 11mm bolts with clean engine oil.
  4.  
  5. Coat the threads of the 8mm bolts with Mopar® Lock and Seal Adhesive.
  6.  
  7. Install the cylinder heads. Use new gaskets and tighten the bolts, in sequence, as follows:
    1. Step 1: Bolts 1-8 to 20 ft. lbs. (27 Nm)
    2.  
    3. Step 2: Bolts 1-10 verify torque without loosening
    4.  
    5. Step 3: Bolts 9-12 to 10 ft. lbs. (14 Nm)
    6.  
    7. Step 4: Bolts 1-8 plus 1 / 4 (90 degree) turn
    8.  
    9. Step 5: Bolts 9-12 to 19 ft. lbs. (26 Nm)
    10.  

  8.  
  9. Install or connect the following:

    Camshaft sprockets. Align the secondary chain matchmarks and tighten the bolts to 90 ft. lbs. (122 Nm).
     
    Secondary timing chain guides
     
    Cylinder head access plugs
     
    Secondary timing chain tensioners. Refer to the timing chain procedure in this section.
     

  10.  
  11. Remove the Timing Chain Locking tool.
  12.  
  13. Install or connect the following:

    Front cover
     
    Crankshaft damper. Torque the bolt to 130 ft. lbs. (175 Nm).
     
    Rocker arms
     
    Power steering pump
     
    Oil fill housing
     
    Accessory drive belt
     
    Engine cooling fan and shroud
     
    Valve covers
     
    Intake manifold
     
    Exhaust Y-pipe
     
    Negative battery cable
     

  14.  
  15. Fill and bleed the cooling system.
  16.  
  17. Start the engine, check for leaks and repair if necessary.
  18.  

3.9L Engine
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Relieve the fuel pressure.
  4.  
  5. Drain the cooling system.
  6.  
  7. Remove or disconnect the following:
    NOTE
    Keep all valvetrain components in order for assembly.



    Negative battery cable
     
    Accessory drive belt
     
    Alternator
     
    A/C compressor, if equipped
     
    Alternator and A/C compressor bracket
     
    Air injection pump, if equipped
     
    Closed Crankcase Ventilation (CCV) system
     
    Air cleaner and hose
     
    Fuel line
     
    Accelerator linkage
     
    Cruise control cable, if equipped
     
    Transmission cable, if equipped
     
    Spark plug wires
     
    Distributor
     
    Ignition coil harness connectors
     
    Engine Coolant Temperature (ECT) sensor connector
     
    Heater hoses
     
    Bypass hose
     
    Intake manifold vacuum lines
     
    Fuel injector harness connectors
     
    Valve covers
     
    Intake manifold
     
    Exhaust front pipe
     
    Exhaust manifolds
     



    Rocker arms
     
    Pushrods
     
    Cylinder heads
     

  8.  

To install:


WARNING
Position the crankshaft so that no piston is at Top Dead Center (TDC) prior to installing the cylinder heads. Do not rotate the crankshaft during or immediately after rocker arm installation. Wait 5 minutes for the hydraulic lash adjusters to bleed down.



Click image to see an enlarged view

Fig. Cylinder head torque sequence-3.9L engine

  1. Install the cylinder heads with new gaskets. Tighten the bolts in sequence as follows:
    1. Step 1: 50 ft. lbs. (68 Nm).
    2.  
    3. Step 2: 105 ft. lbs. (143 Nm).
    4.  
    5. Step 3: 105 ft. lbs. (143 Nm).
    6.  

  2.  
  3. Install or connect the following:

    Pushrods in their original locations
     
    Rocker arms in their original locations. Tighten the bolts to 21 ft. lbs. (28 Nm).
     
    Exhaust manifolds
     
    Exhaust front pipe
     
    Intake manifold
     
    Valve covers
     
    Fuel injector harness connectors
     
    Intake manifold vacuum lines
     
    Bypass hose
     
    Heater hoses
     
    ECT sensor connector
     
    Ignition coil harness connectors
     
    Distributor
     
    Spark plug wires
     
    Transmission cable, if equipped
     
    Cruise control cable, if equipped
     
    Accelerator linkage
     
    Fuel line
     
    Air cleaner and hose
     
    CCV system
     
    Air injection pump, if equipped
     
    Alternator and A/C compressor bracket
     
    Alternator
     
    A/C compressor
     
    Accessory drive belt
     
    Negative battery cable
     

  4.  
  5. Fill the cooling system.
  6.  
  7. Start the engine and check for leaks.
  8.  

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Relieve the fuel pressure.
  4.  
  5. Drain the cooling system.
  6.  
  7. Remove or disconnect the following:
    NOTE
    Keep all valvetrain components in order for assembly.



    Negative battery cable
     
    Accessory drive belt
     
    Alternator
     
    A/C compressor, if equipped
     
    Alternator and A/C compressor bracket
     
    Air injection pump, if equipped
     
    Closed Crankcase Ventilation (CCV) system
     
    Air cleaner and hose
     
    Fuel line
     
    Accelerator linkage
     
    Cruise control cable, if equipped
     
    Transmission cable, if equipped
     
    Spark plug wires
     
    Distributor
     
    Ignition coil harness connectors
     
    Engine Coolant Temperature (ECT) sensor connector
     
    Heater hoses
     
    Bypass hose
     
    Intake manifold vacuum lines
     
    Fuel injector harness connectors
     
    Valve covers
     
    Intake manifold
     
    Exhaust front pipe
     
    Exhaust manifolds
     



    Rocker arms
     
    Pushrods
     
    Cylinder heads
     

  8.  

To install:


WARNING
Position the crankshaft so that no piston is at Top Dead Center (TDC) prior to installing the cylinder heads. Do not rotate the crankshaft during or immediately after rocker arm installation. Wait 5 minutes for the hydraulic lash adjusters to bleed down.



Click image to see an enlarged view

Fig. Cylinder head torque sequence-3.9L engine

  1. Install the cylinder heads with new gaskets. Tighten the bolts in sequence as follows:
    1. Step 1: 50 ft. lbs. (68 Nm).
    2.  
    3. Step 2: 105 ft. lbs. (143 Nm).
    4.  
    5. Step 3: 105 ft. lbs. (143 Nm).
    6.  

  2.  
  3. Install or connect the following:

    Pushrods in their original locations
     
    Rocker arms in their original locations. Tighten the bolts to 21 ft. lbs. (28 Nm).
     
    Exhaust manifolds
     
    Exhaust front pipe
     
    Intake manifold
     
    Valve covers
     
    Fuel injector harness connectors
     
    Intake manifold vacuum lines
     
    Bypass hose
     
    Heater hoses
     
    ECT sensor connector
     
    Ignition coil harness connectors
     
    Distributor
     
    Spark plug wires
     
    Transmission cable, if equipped
     
    Cruise control cable, if equipped
     
    Accelerator linkage
     
    Fuel line
     
    Air cleaner and hose
     
    CCV system
     
    Air injection pump, if equipped
     
    Alternator and A/C compressor bracket
     
    Alternator
     
    A/C compressor
     
    Accessory drive belt
     
    Negative battery cable
     

  4.  
  5. Fill the cooling system.
  6.  
  7. Start the engine and check for leaks.
  8.  

 
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