Updated Surface Preparation and Torque Specs - TSB 276113
NOTE: The intent of the surface preparation procedure is not to remove metal from the head; rather the intent of the procedure is to provide a satiny finish.
CAUTION: The following procedure must be followed carefully for correct surface preparation or damage to the cylinder head may occur.
This procedure SHOULD NOT be used to straighten cylinder heads which are not flat.
DO NOT round off corners of combustion chambers, oil/coolant passages or outer edges of cylinder head.
PROCEDURE
1. Remove cylinder head assembly.
2. Disassemble, clean and inspect the tensioner assembly. Be sure to pay special attention to the oil feed and drain holes. Make sure the oil holes are free of dirt so they will allow proper oil flow. If there is varnish in the tensioner bore or on the plunger that may cause the plunger to stick in the bore, LIGHTLY polish the plunger or bore with SCOTCH BRITE or equivalent. Clean all parts before assembly. Do not use any other method or technique to clean the plunger or bore. Smooth surfaces will ensure the plunger will not stick in the bore. If the plunger still does not operate smoothly, replace the parts. Store the tensioner assembly until it is needed for assembly in a location (e.g., the parts cleaner) where dirt will not get into the oil holes.
CAUTION: Do not use any cleaning material or method that will remove metal from the plunger or bore.
3. Inspect the cylinder head bolts for damaged threads or for damaged heads caused by improper use of tools. Replace head bolts if necessary.
NOTE: Do not use abrasive pads to clean the cylinder head or block surfaces. An abrasive pad may damage the cylinder head or block. Abrasive pads should not be used for the following reasons:
- Abrasive pads will produce a fine grit that the oil filter will not be able to remove from the oil. THIS GRIT IS ABRASIVE AND HAS BEEN KNOWN TO CAUSE INTERNAL ENGINE DAMAGE. Abrasive pads can easily remove enough material to round cylinder head surfaces. This has been known to affect the gasket's ability to seal, especially in the narrow seal areas between the combustion chambers and coolant jackets. The cylinder head gasket is likely to leak if these edges are rounded.
- Abrasive pads can also remove enough metal to affect cylinder head flatness. It takes about 15 seconds to remove 0.203 mm (0.008") of metal from the cylinder head with an abrasive pad. If cylinder head flatness is out of specification, the gasket will not be able to seal and the gasket will leak.
4. Thoroughly clean the cylinder head and block surfaces.
Using Razor Blade Scraper:
- Carefully remove all gasket material. Use a razor blade type scraper, refer to Figure 1.
- Use a NEW razor blade for each cylinder head. Hold the blade as parallel to the gasket surface as possible. This will ensure that the razor blade does not gouge or scratch the gasket surfaces.
- Be careful not to gouge or scratch the gasket surfaces.
- Do not gouge or scrape the combustion chamber surfaces.
The above procedure is the best method for removing gasket material from the cylinder head gasket surfaces. The previously published procedure using chemical gasket removers and a wood or plastic scraper is acceptable too.
Do not use any other method or technique to remove gasket material.
CAUTION: The appearance of the gasket surface is not important, the feel is. There will be indentations from the gasket left in the cylinder head after all the gasket material is removed. These small indentations will be filled in by the new gasket.
- Check cylinder head for flatness. A 1" x 6" x 7" STRAIGHT/FLAT block of cold rolled steel bar stock, with flatness of at least 0.001" (this may require grinding by a machine shop), is required for this procedure.
The steel bar stock can be obtained from a steel supplier, machine shop or tool and die shop. If the steel bar stock cannot be obtained locally, the steel block can be ordered from Alro Steel Corporation (1-800-877-2576). Any burrs or protrusions on the steel bar stock must be filed flat before performing this procedure.
Use the following specifications:
Less Than 0.076 mm (0.003")
Resurface: No
Reuse: Yes
0.076 - 0.25 mm (0.003 - 0.010")
Resurface: Yes
Reuse: Yes
Over 0.025 mm (0.010")
Resurface: No
Reuse: Discard
Inspecing For Corrosion On Cylinder Head:
5. Inspect the cylinder head surface for corrosion or cracks. The combustion seal area will leave a ..shadow" mark on the cylinder head (shaded area - Figure 2). If corrosion is evident outside of the outside diameter (OD) of the combustion seal area (shaded area - Figure 2), the cylinder head may be reused.
If any corrosion extends into this shaded area and/or if cracks are found, the cylinder head should be replaced.
CAUTION: Do Not Use A Tap To Clean The Head Bolt Holes.
Cleaning Cylinder Block:
Cylinder Block Cleaning Brushes:
6. Clean each head bolt seat boss on the cylinder head. Clean the bolt holes in the cylinder block, refer to Figure 3. Use a nylon bristle brush to clean the bolt hole threads, refer to Figure 4.
Caution: Make sure that all puddles of oil and coolant have been removed from bolt holes otherwise the tightening sequence will not obtain the proper clamp load because of hydrostatic lock. if the bolt holes are not cleaned, the head gasket may leak.
Oiling Of Cylinder Head Bolts.:
Oiling Of Cylinder Head Bolts:
7. Apply clean engine oil SPARINGLY to the threads and the bottom side of the flange of the bolt.
NOTE: The following tightening procedure must be used to ensure gasket life. Failure to follow this procedure exactly may result in cylinder head gasket leakage.
Cylinder Head Tightening Sequence:
8. Tighten the head bolts as indicated and in sequence. Refer to image.
- Bolts 1 through 8 (long bolts) 40 Nm (30 lbs. ft.)
- Bolts 9 and 10 (short bolts) 35 Nm (26 lbs. ft.)
- Then turn all 10 bolts 90 degrees in sequence using special tool J 36660 or equivalent.
9. Assemble the rest of the engine.