Cylinder Head Distortion
The contents of this article/image reflects the changes identified in TSB 09-22-1Cylinder Head Distortion
Cleaning and Visual Inspection
1. NOTE: The cylinder head cleaning and the cylinder head distortion check procedures are different than other engines. Watching the video prior to carrying out the procedure may be helpful if doing the procedure for the first time.
2. NOTE: It is important that the cylinder head be thoroughly cleaned prior to taking cylinder head distortion measurements. Failure to remove carbon deposits or other material from measurement areas will result in inaccurate measurements.
Clean the cylinder head. For additional information, refer to Cylinder Head Cleaning.
3. NOTE: Cylinder heads that contain carbon buildup in the coolant areas may show evidence of surface pitting when cleaned. Surface pitting in the coolant areas is not cause for replacement of the cylinder head.
NOTE: Staining of the metal surface is normal and does not affect sealing ability.
NOTE: Witness marks or indentations in the cylinder head resulting from the head gasket fire rings are normal and do not affect sealing ability.
NOTE: The surface finish on the cylinder head may appear to contain "record grooves", which is a normal condition.
NOTE: The cylinder head combustion chamber area may exhibit very small "surface fissures" or "microcracks" during a Magnaflux inspection process. These surface fissures or microcracks are typically located between the glow plug and the valve seats. They DO NOT extend into the coolant jacket and will not cause coolant loss or cooling system overpressurization. The presence of surface fissures or microcracks is not cause for replacement of the cylinder head.
Inspect the cylinder head for obvious signs of damage or distortion.
Cylinder Head Distortion Check
1. NOTE: Do not measure for cylinder head distortion along the length, across the full width, or across a diagonal of the cylinder head. These types of measurement will provide inaccurate results.
Measure only the inboard surface of the cylinder head, from the push rod openings to the outer edge of the exhaust side of the cylinder head.
2. NOTE: When checking the 13 locations on the combustion chamber sealing surface, keep the Feeler Gauge Set away from the valves area as they may lead to incorrect measurements
Check for distortion only at the 13 locations shown.
3. NOTICE: Avoid running the tip of the Feeler Gauge Set into the Gauge Bar (or straightedge). This may cause damage to, or distort the tip of, the Feeler Gauge Set. The result may be inaccurate readings.
NOTE: If the Gauge Bar is not available, use a calibrated straightedge that is calibrated by the manufacturer to be flat within 0.0127 mm (0.0005 in) per running foot length, such as a Snap-On(R) GA438A, or equivalent.
Place the 0.1 mm (0.004 in) feeler gauge on the cylinder head at one of the specified locations. Then place the Gauge Bar (or straightedge) on top of the feeler gauge. Lightly press on the center of the Gauge Bar (or straightedge) while checking the measurement.
4. Attempt to pull the feeler gauge out from under the Gauge Bar (or straightedge).
5. NOTE: If a location is measured to be out of specification, verify that all carbon deposits that may influence measurement accuracy have been removed with a brass scraper and re-measure.
NOTE: The cylinder heads used on the diesel engine cannot be resurfaced. Do not attempt to machine or resurface the cylinder heads.
If the 0.1 mm (0.004 in) feeler gauge can be easily pulled out from under the Gauge Bar (or straightedge) without resistance, the cylinder head is out of specification and must be replaced.
6. Repeat the cylinder head distortion measurement at each of the 13 locations shown.