Piston Protrusion Check

For information on Ford Color Coded Illustrations, refer to OEM COLOR CODING

Special Tool(s) / General Equipment 

Check 

1. Verify that the cylinder block deck surface and the pistons are clean.
2. NOTE: All piston protrusion measurements must fall within the cylinder head gasket numbers. Refer to the SPECIFICATIONS 

   The piston protrusion check is done every 120 degrees around the piston and the cylinder block. Avoid raised or etched markings.

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3. NOTE: Use a commercially available deck bridge such as the Proform® 66797 Magnetic Deck Bridge or equivalent.
   • Using the dial indicator and a commercially available deck bridge, position at one of the points on the cylinder block deck surface.. Use the General Equipment: Dial Indicator
   • Zero the dial indictor on the cylinder block deck surface.

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4. NOTE: Only rotate the crankshaft clockwise.
   NOTE: The piston must remain at TDC or an inconsistent reading will result.
   • Position the dial indicator and a commercially available deck bridge, over the piston.. Use the General Equipment: Dial Indicator
   • Rotate the crankshaft until the piston is at TDC.. Use the General Equipment: Dial Indicator
   • Record the reading.

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5. • Move the dial indicator and the commercially available deck bridge, to the cylinder block deck surface at the opposite position.. Use the General Equipment: Dial Indicator
   • Zero the dial indictor on the cylinder block deck surface.

   Courtesy of FORD MOTOR COMPANY

6. • Move the dial indicator and the commercially available deck bridge, onto the piston at the opposite position.. Use the General Equipment: Dial Indicator
   • Record the reading.

   Courtesy of FORD MOTOR COMPANY

7. • Move the dial indicator and the commercially available deck bridge, to the cylinder block deck surface at the opposite position.. Use the General Equipment: Dial Indicator
   • Zero the dial indictor on the cylinder block deck surface.

   Courtesy of FORD MOTOR COMPANY

8. • Move the dial indicator and the commercially available deck bridge, onto the piston at the opposite position.. Use the General Equipment: Dial Indicator
   • Record the reading.

   Courtesy of FORD MOTOR COMPANY

9. Average the readings and record.
10. Repeat on the remaining pistons.
11. Determine the cylinder head gasket thickness. Refer to: Specifications .