GASKET 9N6098 - Caterpillar

C-10 (8YS),
C-12 (9NS) Truck EnginesThe above truck engines are changed for the 1998 model year. The changes include performance related components, additional new ratings, and serial number prefixes identifying the changes. The changes provide:
1998 Model Year Changes:
* Increased horsepower on the C-12 Truck Engine (up to 430 hp).* Improved fuel economy.* Improved lube oil life.* Improved "Emissions" for 1998 EPA regulations.* Improvement to lessen exhaust lube oil leakage. Component Changes:
The performance improvements listed above are accomplished by an increase in the fuel injection pressure. Changes in the fuel injection spray are matched to a deeper piston crater. The C-12 Truck Engine has reduced air flow. There are changes to the valve stem oil shields. The gear train has increased strength.
The following, lists the parts that are changed:
* Unit injector - nozzle spray pattern is changed.* Camshaft - fuel cam profile is changed.* Piston crown - has a deeper piston crater.* Turbocharger - there is an addition of a wastegate on the C-12 Truck Engine.* Valve stem shields - has umbrella type oil shields (previously had the flat type).* Crankshaft gear - has wider teeth. Rating Changes:
Three new ratings are available on the C-10 Truck Engine:
* 305 hp-1428 N m (1050 lb ft)-2100 RPM Governed speed.* 335 hp-1700 N m (1250 lb ft)-2100 RPM Governed speed.* 350 hp-1836 N m (1350 lb ft)-2100 RPM Governed speed. The former 280 hp ratings are no longer available.Seven new ratings are available on the C-12 Truck Engine:
* 355 hp-1836 N m (1350 lb ft)-2100 RPM Governed speed.* 380 hp-1836 N m (1350 lb ft)-2100 RPM Governed speed.* 395 hp-1972 N m (1450 lb ft)-1800 RPM Governed speed.* 395 hp-1972 N m (1450 lb ft)-2100 RPM Governed speed.* 430 hp-2244 N m (1650 lb ft)-1800 RPM Governed speed.* 430 hp-2244 N m (1650 lb ft)-2100 RPM Governed speed.* 380/430 MT-1972 N m (1450 lb ft) to 2244 N m (1650 lb ft)-1800 RPM Governed speed. The former 360 hp and 390 hp ratings are no longer available. Earlier model C-10 and C-12 Truck Engines can not be re-rated to the above ratings because of the performance iron changes involved. Both the C-10 and C-12 Truck Engine serial number prefixes are changed as above.