1993 Cadillac Seville Owner's Manual - Page 351

I The Northstar engine is designed to require less maintenance than many other DOHC V-8 engines. Engine systems are designed to remind the driver when service required. An oil life index indicator monitors is ongoing operating conditions and reminds the driver whenan oil change is needed. A low coolant warning message keeps track of the level of this vital fluid.Direct acting hydraulic tappets provide maintenance free zero lash operation of the 32 valvesfrom idle to the 6500 rpm redline. The camshafts are driven by a two stage roller chain assembly which is designed to provide quiet maintenance free operation. Platinum tipped spark plugs increase the replacement interval to 100,OO miles. The four valve per cylinder design provides more efficient engine breathing which results in higher power than comparable two valve engines. The central location of each spark plug ensures a fast and complete burning of the fuel/air mixture. The induction system uses smooth thermoplastic tubes to channel air into the cylinders. The port smoothness of the tubes is equivalent to the elaborate polishing methods used for race car engines. Careful design usingthe shape and length of the tubes boosts horsepower by using sonicpressure waves created by the motion of the inlet valves to increase the amountof air entering each cylinder. The Northstar engine is also designed to be very durable. The aluminum block has cast-in-place iron cylinder liners for greater wear resistance. High strength forged steel connecting rods support the freefloating piston pinsin bronze bushings for superior high speed performance. The fillits of the nodular iron crankshaft undergo a high pressure compression rolling operation to improve their resistance to fatigue. Quiet operation is enhanced by the use of special materials and designs. The front cover of the engine is stamped from laminated steel which damps out noise. Special cam cover gasket seals isolate valve train operation. The fuel injectors are placed inside the induction system housing to eliminate the clicking noise which common to otherfuel is injected engines. The Northstar engine is designed to provide yearsof efficient, reliable, satisfying operation. We think it is also just plain fun to drive. 337