Ford Mustang 1994-1998 Repair Guide

Rocker Arms

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REMOVAL & INSTALLATION



3.8L Engine

See Figures 1 through 4

During this procedure, always keep the parts in order so that they may be reinstalled in their original positions.

  1. Remove the valve cover(s) from the engine.
  2.  
  3. Loosen the rocker arm fulcrum (seat) mounting bolts from the cylinder head, then lift the rocker arms, fulcrums and bolts off of the head.
  4.  
  5. If necessary, the pushrods may be removed from the engine at this time. If removing more than one pushrod at a time, be sure to label them so that they can be installed in their original positions.
  6.  



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Fig. Fig. 1: After removing the valve cover, loosen the rocker arm mounting bolt ...



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Fig. Fig. 2: ... then lift the rocker arm, mounting bolt and fulcrum off of the cylinder head



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Fig. Fig. 3: The mounting bolt (A), fulcrum (B) and rocker arm (C) can be separated once removed from the head



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Fig. Fig. 4: If necessary, the pushrod may be removed at this point

To install:
  1. If applicable, install the pushrods in their original positions, after lubricating their tips with engine assembly lube (such as Ford D9AZ-19579-D).
  2.  
  3. Lubricate the rocker arms and fulcrums with engine assembly lube prior to installation.
  4.  
  5. Install each rocker arm, one at a time, as follows:
    1. Rotate the crankshaft so that the valve lifter (tappet), which corresponds to the rocker arm being installed, rests on the base circle of the camshaft (the camshaft lobe points away from the valve lifter). This position can be found by depressing the pushrod while having an assistant rotate the crankshaft with a socket and ratchet wrench on the crankshaft pulley/damper center bolt; when the pushrod is at its lowest point, the lobe is pointing away from the lifter.
    2.  
    3. Position the rocker arm over the pushrods and mounting bolt holes.
    4.  
    5. Install the rocker arm fulcrum and mounting bolt. Tighten the mounting bolt to a maximum of 44 inch lbs. (5 Nm).
    6.  

  6.  
  7. Perform Step 4 for each of the rocker arms requiring installation.
  8.  

For the final-tightening of the rocker arm mounting bolts, the camshaft can be in any position.

  1. Final-tighten the rocker arm fulcrum bolts to 19-25 ft. lbs. (25-35 Nm) for 1994-95 models, and to 23-29 ft. lbs. (30-40 Nm) for 1996-98 models.
  2.  
  3. Install the valve cover(s).
  4.  

4.6L Engines

See Figures 5, 6 and 7

On this engine, the cam followers (rocker arms) are part of the hydraulic valve lash adjustment assembly. The hydraulic lash adjusters are placed at the fulcrum point of the rocker arms and act in a manner similar to hydraulic lifters in pushrod engines.

Be sure to keep the rocker arms and valve tappets in order so that they can be installed in their original positions.



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Fig. Fig. 5: Primary intake, secondary intake and exhaust valve locations on the DOHC engine

  1. Remove the valve covers.
  2.  

The only difference between the SOHC and DOHC engines for this procedure is simply that the DOHC engine has twice as many valves, rocker arms and valve tappets. The removal and installation technique is the same, regardless of which valve is being serviced, or which engine is being serviced.

  1. Rotate the crankshaft so that the position of the piston in the cylinder being serviced is at the bottom of its stroke, and the base circle of the camshaft is resting against the rocker arm.
  2.  


WARNING
A valve spring spacer, such as Ford Tool T91P-6565-AH, must be used in order to prevent the valve spring retainer from contacting the valve stem seal, which can result in damage to the seal.

  1. Install the valve spring spacer between the valve spring coils.
  2.  
  3. Install a valve spring compressor, such as Ford Tool T91P-6565-A, under the camshaft and on top of the valve spring retainer.
  4.  



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Fig. Fig. 6: To properly depress the valve and spring, use both the valve spring spacer and compressor tools



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Fig. Fig. 7: Although equipped with twice as many valves, removal and installation of the rocker arms on the DOHC engine is essentially the same as on the SOHC engine

  1. Slowly push down on the compressor tool until the spring is depressed far enough to allow the rocker arm to be removed, then pull the rocker arm out from underneath the camshaft.
  2.  
  3. Remove the valve spring compressor and spacer tools.
  4.  
  5. Repeat Steps 2 through 6 for all of the rocker arms needing removal.
  6.  
  7. If necessary, pull the hydraulic valve tappets out of the cylinder head(s).
  8.  
  9. Thoroughly clean the valve tappets and rocker arms with clean solvent, then wipe them with a lint-free cloth. Do not immerse the valve tappet in solvent.
  10.  
  11. Inspect the valve tappet, and discard it if any part shows signs of pitting, scoring, or excessive wear.
  12.  

To install:
  1. Apply clean engine oil to the valve stems and tips, the rocker arm roller surfaces, the valve tappets, and the valve tappet bores in the cylinder head(s).
  2.  

The valve tappets must not have more than 0.059 in. (1.5mm) of plunger travel prior to installation.

  1. If removed earlier, insert the tappets in their original bores in the cylinder head(s).
  2.  
  3. Rotate the crankshaft so that the position of the piston in the cylinder being serviced is at the bottom of its stroke, and the base circle of the camshaft is facing where the rocker arm will be installed.
  4.  
  5. Install the valve spring spacer and compressor tools as before.
  6.  
  7. Carefully depress the valve spring with the compressor tool until the rocker arm can be positioned between the valve stem and valve tappet, and the camshaft.
  8.  
  9. Slowly allow the valve spring to decompress, and ensure that the rocker arm is properly retained.
  10.  
  11. Remove the valve spring compressor and spacer tools.
  12.  
  13. Repeat Steps 13 through 17 for all of the rocker arms.
  14.  
  15. Install the valve covers.
  16.  
  17. Start the engine and check for oil leaks from the valve cover gaskets.
  18.  

5.0L Engine

See Figures 8, 9, 10 and 11

  1. Disconnect the negative battery cable for safety purposes.
  2.  
  3. Remove the upper intake manifold assembly.
  4.  
  5. Remove the valve covers.
  6.  



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Fig. Fig. 8: Exploded view of the rocker arm assembly-5.0L engine (except Cobra)



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Fig. Fig. 9: Exploded view of the rocker arm assembly-5.0L engine (Cobra)

  1. For non-Cobra models, loosen the rocker arm fulcrum bolt, then remove the bolt, fulcrum (seat), rocker arm and guide. KEEP ALL PARTS IN ORDER FOR INSTALLATION!
  2.  

Label and/or arrange all rocker arm and fulcrum components to assure installation in their original locations.

  1. On the Cobra, loosen the fulcrum bolt, then remove the bolt, roller rocker arm assembly and pedestal assembly.
  2.  



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Fig. Fig. 10: Loosen and remove the fulcrum bolt ...



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Fig. Fig. 11: ... then lift the rocker arm assembly from the engine-5.0L engine

To install:
  1. Inspect the fulcrum bolts for damage. Replace any bolt on which damage is found.
  2.  
  3. Inspect the rocker arm and fulcrum seat or roller contact surfaces for wear and/or damage. Also check the rocker arm for wear on the valve stem tip contact surface and the pushrod socket. Replace complete rocker arm assemblies, as necessary.
  4.  
  5. Inspect the pushrod end and the valve stem tip. Replace pushrods, as necessary. If the valve stem tip is worn, the cylinder head must be removed to replace or machine the valve.
  6.  
  7. Lubricate the rocker arms and fulcrum seats with heavy engine oil or pre-assembly lube before installation.
  8.  
  9. Apply multi-purpose grease to the valve stem tips, the underside of the fulcrum seats and the sockets.
  10.  
  11. Rotate the crankshaft until the tappet is on the base circle of the camshaft lobe (all the way down), then install the rocker arm assembly. Tighten the fulcrum bolt to 18-25 ft. lbs. (24-34 Nm).
  12.  
  13. Install the valve covers.
  14.  
  15. Install the upper intake manifold assembly.
  16.  
  17. Connect the negative battery cable.
  18.  

ROCKER ARM-TO-VALVE STEM CLEARANCE



See Figures 12, 13, 14 and 15

This procedure is applicable only to pushrod engines (3.8L and 5.0L engines); the OHC engines (4.6L engines) utilize automatic hydraulic lash adjusters.

No periodic valve lash adjustments are necessary or possible on these engines. Even though the 3.8L and 5.0L engines utilize hydraulic valve trains to automatically maintain proper valve lash, if one of these engines is determined to have a valve tap, the following inspection procedures can help determine whether the valve tappet is to blame.



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Fig. Fig. 12: Use a tappet bleed down wrench and a feeler gauge to check valve clearance



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Fig. Fig. 13: Measure the clearance between the tip of the rocker arm and valve stem tip as shown



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Fig. Fig. 14: To check all of the valves on the 3.8L engine, the crankshaft must be rotated to two different positions



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Fig. Fig. 15: To check all of the valves on the 5.0L engine, the crankshaft must be turned to 3 different positions

The valve lash is not adjustable. If the collapsed lifter clearance is incorrect, different length replacement pushrods are available to compensate. However, the reason for the incorrect clearance should be investigated first. The clearance could be wrong for a number of reasons, such as: worn camshaft lobe, bent pushrod, bent rocker arm, worn valve stem tip, etc.

  1. Remove the valve cover(s) for access to the valves whose lash is being checked.
  2.  

An easy way to tell if a cylinder is at TDC of the compression stroke is to watch that cylinder's valves as the engine is cranked or rotated. If the valves remain closed (the rocker arms don't move) as the piston approaches the top of its travel, that piston is on its compression stroke (the closed valves were allowing compression to build). If, instead, a valve opens as the piston travels upward (releasing compression in that cylinder), then that piston is on its exhaust stroke.

  1. Either have an assistant help by cranking the engine or install a remote starter switch. Crank the engine with the ignition switch OFF until No.1 piston is at TDC on the compression stroke.
  2.  

Follow the tool manufacturer's instructions when installing the remote starter switch. In most cases, the BROWN lead (terminal I) and the RED/BLUE lead (terminal S) at the starter relay should be disconnected. Then, install the remove starter switch between the battery and terminal S of the relay.

  1. With the crankshaft in the positions designated in the steps below, position a lifter bleed-down wrench, such as Tool T71P-6513-B or equivalent, on the rocker arm. Slowly apply pressure to bleed down the lifter until the plunger is completely bottomed. Hold the lifter in this position and check the available clearance between the rocker arm and the valve stem tip with a feeler gauge.
  2.  
  3. The clearance should be 0.09-0.19 in. (2.25-4.79mm) for 3.8L engines, or 0.123-0.146 in. (3.1-3.7mm) for 5.0L engines. If the clearance is less or more than specified, investigate the reason. If everything checks out OK, install a shorter (too little clearance) or longer (too much clearance) pushrod to compensate.
  4.  
  5. The following valves can be checked with the crankshaft at position No. 1, with the No. 1 piston at TDC on the compression stroke:
  6.  

3.8L engine


No. 1 intake and exhaust
 
No. 2 exhaust
 
No. 3 intake
 
No. 4 exhaust
 
No. 6 intake
 

5.0L engine


No. 1 intake and exhaust
 
No. 3 exhaust
 
No. 4 intake
 
No. 7 exhaust
 
No. 8 intake
 

  1. Rotate the engine 360° (1 full revolution) from the 1st position (No. 1 is now on its exhaust stroke) and check the following valves:
  2.  

3.8L engine


No. 2 intake
 
No. 3 exhaust
 
No. 4 intake
 
No. 5 intake and exhaust
 
No. 6 exhaust
 

5.0L engine


No. 2 exhaust
 
No. 3 intake
 
No. 6 exhaust
 
No. 7 intake
 

  1. For the 5.0L engine, rotate the engine 90° ( 1 / 4 revolution) from the 2nd position and check the following valves:

    No. 2 intake and No. 4 exhaust
     
    No. 5 intake and No. 5 exhaust
     
    No. 6 intake and No. 8 exhaust
     

  2.  

 
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