TM 5-6115-584-34NAVFAC P-8-622-34TO-35C2-3-456-2TM-0568C-347-9.a.CYLINDERHEAD.Removal (see figure 7-9).(1) Remove. Refer to the Operator andOrganizational Maintenance Manual and remove airshutter assembly and intake and exhaust manifold,muffler and shroud assembly. Remove engine liftingbracket, rocker cover and gasket, fuel nozzles, andconnecting oil lines to cylinder head.(2) Remove rocker arms by removing the self-locking rocker arm nuts (1, figure 7-9), rocker armballs (2) on each rocker arm (3). Lift rocker arm (3)off.(3) Remove capscrews (4) and push rod guideplate (5), screws (6) and washers (7) holding eachcylinder head (8) to cylinder block (9).(4) Remove push rod (15) and remove cylinderhead. If head sticks, rap sharply with a soft hammer.Do not use a pry, Do not strike the cooling fins.(5) Remove push rod shield (17) and packings (16),spring (18) and washers (19).(6) Remove cylinder head gasket (10).b. Disassembly (see figure 7-11).(1) Remove valve rotator (l). Using a valvespring compressor (see figure 7-10), disassemblevalve assemblies. Valve assemblies include springretainer lock (2), (see figure 7-11), retainer (3), valvespring (5) and valves (8) and 10).(2) Remove intake valve seals (4).c. Clean and Inspect. Thoroughly clean all compo-nents of cylinder head assembly. Remove all carbondeposits from intake and exhaust ports and clean allgasket surfaces. Inspect all cylinder head componentsfor physical damage. Inspect cylinder head firing deckfor warpage by measuring the maximum gap betweenthe cylinder head and a steel straightedge placed inline and at a right angle to the cylinder head. If thegap exceeds the value in Table 1-2 in any direction,replace cylinder head.d. Repair.(1) Valves. Remove all carbon and check eachvalve (8 and 10, figure 7-11) for burning, pitting orwarped head. Valves that are slightly pitted or burned,refinish on a valve grinder. Refinish intake valves toa 44° angle and exhaust valves to a 45° angle. But, ifthey are badly pitted, or will have a thin edge whenrefacing, replace them. Check refinished valves for atight seat to the valve seat (7) with an air pressuretype testing tool or by applying Prussian Blue on thevalve face and rotating it against the seat.(2) Valve Guides. Check valve guides (6 and 9,figure 7-11) to valve clearance. See table 1-2. If theproper clearance cannot be obtained by replacingvalve, replace valve guides. Drive the old valve guidesinto valve chambers. Drive new intake guides (6) inuntil they protrude 11/32 inch from the rocker coverside of the head. Ream new valve guide to obtain theproper clearance. Exhaust guides (9) should protrude5/8 inch from rocker cover side of the head.(3) Valve Seats. If the valve seats (7, figure 7- 11)are pitted, refinish them. Using seat grinding equip-ment, reface each seat to a value given in table 1-2.Seat width should be 3/64 to 1/16 inch for exhaust and1/16 to 3/32 for intake. A seat can be refaced severaltimes before it becomes necessary to replace it. If,however, the valve seats are loose or cannot be re-faced, replace them. Adjust tool to cut 1/64 inch fromedge of seat. Oil the pilot to prevent it from seizing inthe valve guide. Cut each seat down to a narrow ridgeon edges and bottom and break it out with a sharp tool.7-10Change 3
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