Engine Inspection and Repair
Fig. 13 Checking cylinder head flatness:
CYLINDER HEAD
1. Inspect for coolant leakage, fuel leakage, damage and cracks. Replace cylinder head as necessary.
2. Check that distortion does not exceed .004 inch, in 6 planes shown in Fig. 13. If distortion is excessive, replace cylinder head. Do not attempt to mill head.
3. Check that manifold contact surface distortion does not exceed .008 inch. Mill or replace head as necessary.
Fig. 14 Checking combustion chamber insert projection:
COMBUSTION CHAMBER INSERT
1. Check combustion chamber insert projection, Fig. 14. Chamber must not project less than .0016 inch or project more than .0024 inch. If either limit is exceeded, replace insert or cylinder head as necessary.
VALVE SEATS
1. Using straightedge and feeler gauge, measure valve recession from cylinder head surface. If valve has receded .061-.100 inch, install an equivalent shim under valve seat. If valve has receded more than .100 inch, replace cylinder head.
2. Check valve seat for roughness or damage. Check contact width by applying red lead to valve seat and pressing valve against seat.
Fig. 15 Valve seat cutting angles:
3. Use 15, 45, or 60 degree valve seat cutter to remove roughness or scars. Maintain minimum valve seat contact width of .067-.091 inch, Fig. 15.
4. Seat valve by applying thin coat of engine oil and small amount of compound to seat surface. Lightly tap while turning valve.
VALVES
1. Inspect each valve and replace any that show valve stem wear, damage, bending or nicks. Intake valve stem diameter should be .3138-.3144 inch; exhaust valve stem diameter should be .3136-.3142 inch.
2. Check valve faces for roughness or damage. Reface or replace valve as necessary.
VALVE GUIDES
Fig. 16 Determining valve stem clearance:
1. Check difference between valve guide inner diameter and valve stem diameter. Replace valve guide if clearance exceeds .004 inch, Fig. 16.
Fig. 17 Driving out valve guide:
2. Drive valve guide out through top of cylinder head, away from combustion chamber, Fig. 17.
Fig. 18 Installing new valve guide:
3. Install clip on new valve guide, and tap valve guide in from top of cylinder head until clip barely contacts cylinder head, Fig. 18. Note that exhaust valve guides are shorter than intake valve guides. After guide is installed, check valve guide clearance again.
VALVE SPRINGS
1. Inspect each valve spring for cracks or other damage.
2. Check that free length of each spring is 1.764 inches. Check that variation from perpendicular does not exceed .062 inch.
TAPPET & ADJUSTING DISC
1. Check that tappet outer diameter is 1.3763-1.3771 inches. If not, replace tappet.
2. Check that inner diameter of tappet bore is 1.3776-1.3787 inches. Clearance between tappet and bore should be .0008-.0024 inch and must not exceed .0040 inch.
CAMSHAFT
1. Measure camshaft lobe height. Standard intake lobe height is 1.744 inches, and must be no less than 1.728 inches. Standard exhaust lobe height is 1.783 inches, and must be no less than 1.768 inches.
Fig. 19 Checking camshaft wear:
2. Measure journal wear at four places as shown in Fig. 19. Standard journal diameter is 1.258-1.259 inches and should be no less than 1.254 inches.
3. Check that camshaft runout does not exceed .0040 inch.
4. Remove tappets and adjusting discs noting their locations. Clean oil and dirt from camshaft and cylinder head journal. Set plastic gauge on camshaft journal. Install camshaft journal cap and torque to 15-20 ft.lbs. Remove camshaft cap and check clearance. Clearance should be .00098-.0026 inch and must not exceed .0039 inch. If clearance is excessive, camshaft or cylinder head must be replaced.
5. Check that camshaft endplay is .00079-.00591 inch. Endplay must not exceed .0079 inch.
ENGINE BLOCK
1. Check each cylinder for damage and cracks. Replace as necessary.
2. Check that block deck distortion is no more than .0040 inch. If distortion is excessive, block must be replaced as deck surface cannot be machined since valves would hit pistons.
3. Check cylinder walls for signs of seizing or scoring. If necessary, rebore or replace block.
4. If upper part of cylinder shows uneven wear, use ridge reamer to repair.
Fig. 20 Areas for checking bore wear:
5. Measure cylinder at points shown in Fig. 20. Standard bore is 3.386-3.387 inches and must be no less than 3.39 inch. Difference between cylinder bore measurements should not exceed .0009 inch. Pistons are available in .010 and .020 inch oversizes.
PISTONS & RINGS
1. Inspect piston circumference for scoring or seizing. Replace as necessary.
Fig. 21 Area for measuring piston skirt:
2. Measure piston outside diameter in thrust direction, Fig. 21. Standard piston diameter is 3.384-3.385 inch. Piston to bore clearance should not exceed .006 inch. If piston is replaced, replace piston rings also. Piston rings are available in .010 and .020 oversizes.
3. Inspect piston rings for damage, abnormal wear, or breakage. Replace as required.
4. Insert piston in bore and push in using a piston. Check that ring end gap does not exceed .039 inch.
5. Check that piston ring side clearance does not exceed .008 inch.
CONNECTING RODS
1. Check that connecting rod bend does not exceed .006 inch per 3.94 inches.
2. Check that connecting rod twist does not exceed .006 inch per 3.94 inches.
3. Measure clearance between outer diameter of piston pin and inner diameter of bushing. Standard bushing diameter is .9846-.9854 inch. Clearance between pin and bushing must not exceed .002 inch.
4. If necessary, replace connecting rod bushing using a press and a pipe 1.06-1.88 inch in diameter. Oil new bushing and connecting rod. Align bushing oil hole and connecting rod oil hole and press bushing in. Ream out bushing to correct diameter.
CRANKSHAFT
1. Check main and rod journals for damage, scoring, and clogged oil holes.
2. Check that crankshaft runout does not exceed .002 inch.
3. Measure journal diameters:
a. Main journals, 2.360-2.361 inches.
b. Connecting rod journals, 2.0055-2.0063 inches.
c. Oil seal surface of crankshaft flange, 3.541-3.543 inches. Wear should not exceed .0020 inch on any journal. If wear is excessive, crankshaft must be reground. Do not remove more than .0295 inch. Bearings are available in .010, .020, and .0295 inch undersizes.
4. When grinding crankshaft, maintain a fillet R dimension of .102-.118 inch.
MAIN & CONNECTING ROD BEARINGS
1. Check main and connecting rod bearings inside surfaces for streaking, flaking, pin holes, etc. If any damage is found, replace all bearings as set.
TIMING BELTS
Inspect timing belts for following conditions and replace belt(s) as necessary. Never twist or kink timing belt. Do not allow oil, grease, or moisture on timing belt.
1. Premature breakage - check for proper installation. Check that timing belt cover gaskets are installed and not damaged.
2. Cracked, damaged or missing teeth.
3. Noticeable wear or cracks on belt face.
4. Wear or damage on one side only.
5. Noticeable wear on belt teeth.
TIMING BELT TENSIONER
Check rotation of tensioner pulley. Check for play or abnormal noise. Replace as necessary. Do not immerse tensioner in cleaning fluid. If dirty, clean with rag to avoid scratching tensioner.
TIMING BELT SPROCKETS
Inspect sprocket teeth for wear, deformation, or other damage. Replace if necessary. Make sure sprocket is free of oil and grease.
TIMING BELT COVERS
1. Inspect each timing cover for deformation or cracks. Replace, if necessary.
2. Inspect gasket for deformation, cracks, or hardening. Replace, if necessary.