LINK 3T8408 - Caterpillar

(5FG, 9CG, 4TJ, 78P, 2ER, 43V, 46V, 48V, 07Z, 09Z, 12Z, 59Z) And 3306 (3LC, 6NC, 1TF, 2JG, 6KJ, 03N, 9BN, 44V, 47V, 49V, 08Z, 10Z, 13Z, 62Z) Engines In Caterpillar MachinesSUPPLEMENT: OCTOBER 19, 1998Service Magazine SEPD0422, Article 38, Page 28, June 22, 1998; "New Cast Iron Valve Guide And New Exhaust Valve With Chrome Plated Stem Will Help Prevent Early Hour Exhaust Valve Sticking In 3304 And 3306 Machine Engines".The following information should be added to the end of the first paragraph of the "Adaptable To" section:
The new 148-7425 Valve Guide (cast iron) may be used with any 3300 exhaust valve, but to obtain reduced valve guide wear, the new 148-7455 Exhaust Valve (chrome plated stem) should be matched with the new 148-7425 Valve Guide.
--------------- END SUPPLEMENT ---------------Description of Change: New cast iron valve guides and new exhaust valves with chrome plated stems are used in these machine engines. The new threaded bore cast iron valve guides replace the former smooth bore powder metal valve guides. The new cast iron valve guide is an improvement over earlier cast iron valve guides for the following reasons: * The cast iron material in the new valve guides is improved for greater wear resistance.* The inner diameter of the uninstalled new guide is larger than the inner diameter of the earlier cast iron guide (9.515 mm versus 9.502 mm (.3746 in versus .3741 in) for greater hot running clearance (to reduce guide wear).* The "teepee top" design of the new guide will reduce the amount of oil drawn into the valve stem/guide bore clearance because the oil has no place to collect where it can be fed into the clearance.In addition to the change in the valve guide material, the exhaust valve stem will now be chrome plated for increased guide wear resistance. The new exhaust valve MUST be used with the new valve guide and the new exhaust valve may be used with the former valve guides.
Adaptable To: The new 148-7425 Valve Guide (cast iron) replaces the former 109-0390, 116-7553, and 148-7502 Valve Guides. The new 148-7455 Exhaust Valve (chrome plated stem) replaces the former 100-7861 Exhaust Valve. The former valve guides and exhaust valve are canceled. These changes are in effect with 3304 (07Z34060-Up, 12Z52865-Up) and 3306 (6NC4980-Up, 13Z42490-Up) Engines In Caterpillar machines. The new valve guide and exhaust valve, when used togather, are adaptable to all 3304 and 3306 Machine Engines. Use the 9U-6954 Guide Collar with a 9U-7349 Driver for parts service installation of the new 148-7425 Valve Guides in the cylinder head.