Valve Clearance

Tools Required:

• Tappet Bleed Down Wrench T71P-6513-B

The valve arrangement of the LH bank is E-I-E-I-E-I-E-I and of the RH bank is I-E-I-E-I-E-I-E.

A 1.52mm (0.060-inch) shorter push rod or a 1.52mm (0.060 inch) longer push rod is available for service to provide a means of compensating for dimensional changes in the valve mechanism. Refer to the Master Parts List or the Specifications listed for the pertinent color code.

Valve stem-to-valve rocker arm clearance should be within specification with the hydraulic tappet completely collapsed. Repeated valve reconditioning operations (valve and/or valve seat refacing) will decrease the clearance to the point that, if it is not compensated for, the hydraulic valve tappet will cease to function and the valve will be held open.

The valve stem-to-valve rocker arm clearance is not adjustable. However, to obtain the specified valve clearance, it is important that all valve components be in a serviceable condition and installed and tightened properly.

To determine whether a shorter or a longer push rod is necessary, make the following check:

1. Disconnect the brown lead ("I" terminal) and the red and blue lead ("S" terminal) at the starter relay.

2. Install an auxiliary starter switch between the battery and "S" terminals of the starter relay. Crank the engine with the ignition switch OFF until the No. 1 piston is on TDC on the compression stroke.

   NOTE: Tappet Bleed Down Wrench T71P-6513-B will not fit on the Mustang Cobra roller rocker arms.

3. With the crankshaft in the positions designated in Steps 4, 5 and 6, position Tappet Bleed Down Wrench T71P-6513-B on the rocker arm. Slowly apply pressure to bleed down the tappet until the plunger is completely bottomed. Hold the tappet in this position and check the available clearance between the rocker arm and the valve stem tip with a feeler gauge.
   
   
   
   

4. With the No. 1 piston on TDC at the end of the compression stroke, POSITION 1, check the following valves:
   • No. 1 intake No. 1 exhaust
   • No. 4 intake No. 3 exhaust
   • No. 8 intake No. 7 exhaust

5. After these valves have been checked, rotate the crankshaft to POSITION 2, check the following valves:
   • No. 3 intake No. 2 exhaust
   • No. 7 intake No. 6 exhaust

6. After these valves have been checked, rotate the crankshaft to POSITION 3, check the following valves:
   • No. 2 intake No. 4 exhaust
   • No. 5 intake No. 5 exhaust
   • No. 6 intake No. 8 exhaust

   NOTE: If the clearance is less than specification, install a shorter push rod. If the clearance is greater than specification, install a longer push rod.