ARMY TM 9-2815-259-24 AIR FORCE TO 38G1-125-2 MARINE CORPS 09249A/09246A-24 5-118 (7) Recheck valve recess, refer to paragraph 4.7.4.(b). (8) Test cylinder head prior to installation, refer to paragraph 4.7.4.c. (9) Install cylinder head, refer to paragraph 4.7.4.d. 5.4.12.   OIL PRESSURE REGULATING VALVE ASSEMBLY VALVE SEAT. NOTE The following procedure requires complete access to the engine.  If necessary, remove engine from generator set, refer to TM 9-6115-671-14.   Mount engine on repair stand (NSN 4910-01-016-1835 or equal) as outlined in paragraph 4.10. a.    Replacement. Inspect oil pressure regulating valve assembly, refer to paragraph 4.5.2.b.  Replace oil pressure regulating valve (4, Figure 4-39) and valve seat (5) if cone of valve is found defective.  Refer to the following steps for removal and replacement of valve seat (5); (1) Remove oil pressure regulating valve, refer to paragraph 4.5.2.a. (2) Remove valve seat (5) using collet (JT01727) and slide hammer (JT01718).  Discard valve seat. CAUTION Valve seat bore is easily damaged.  Do not drive against raised inner rim of valve seat.  Failure to comply could result in damage to cylinder block. (3) Install new valve seat (5) using oil pressure relief valve bushing driver (JD248A) and handle (JDG536).  Drive valve seat into cylinder block until valve seat bottoms in bore. (4) Install oil pressure regulating valve, refer to paragraph 4.5.2.d.