The first vehicle to receive the 4.7 will be the newly redesigned
1999 Jeep Grand Cherokee, which will carry that engine across the world.
International buyers will also have the option of a new turbocharged
Diesel engine, and both American and international buyers can get an
updated version of the 4.0 straight-six currently in use.
The all-new 4.7-liter V-8 engine, Chrysler's first new V-8 family since
the 1960s, will have more power, less weight, increased fuel efficiency,
and lower emissions than the LA series 318 - a member of the current youngest,
and sole remaining, V-8 family.
It will be mated with an all-new, electronically-controlled transmission
with five forward ratios. An alternate second gear ratio will provide
improved performance.
The V-8 engine will have 230-horsepower (172 kW) and 295 lb.-ft. (400 Nm)
of torque,
roughly comparable to the 318. It produces 30% less pollution, noise,
vibration,
and harshness. Fuel economy is 7% better (all compared with the current
318/5.2)
- with the new four-speed automatic, the engine has more pulling power,
faster initial
acceleration, and three miles per gallon better economy.
The new engine has a cast iron block and two cast aluminum cylinder heads with
a single overhead camshaft per bank and two valves per cylinder. It
displaces 4701
cm3 (287 cu in.). A relatively small bore of 3.66 inches (93 mm) helped reduce
overall length of the engine, packaging it for the compact engine bay of
the Grand
Cherokee. The stroke is 3.4 inches (86.5 mm).
Breathing features include a new tuned-length runner intake manifold,
free-flowing
intake and exhaust ports and fast-burn combustion chambers. Operating with
a high
9.3:1 compression ratio, the engine still only requires regular-grade fuel.
Lightweight material applications and more efficient engine accessories
such as
the alternator, power steering pump and air conditioning compressor further
bolster
performance and economy. Aluminum cylinder heads, a hollow camshaft with
sintered
steel lobes, magnesium valve covers and a molded composite intake manifold
contribute to an overall weight reduction of 54 pounds (24 kg) compared to the
previous 5.2-liter engine.
Driveability is enhanced by variable fuel injection timing, sequential
multi-port injection,
a quick-sensing inlet-side positioned thermostat and coil-on-plug ignition,
in which
each individual spark plug has its own secondary ignition coil.
In order to improve fuel economy, the new engine features a patented hybrid
cooling fan system that combines in-line electric and engine-driven fans.
This system
allows the engine fan to idle at a very low speed (250-300 rpm. vs. the
typical 650-700 rpm.),
decreasing noise and vibration at idle and low speeds. The newly designed
cooling system, with a high efficiency water pump and a secondary
thermostat control,
reduces power consumption by 12 percent (6 bhp/4.5 kW).
The new coil-on-plug ignition system, two-stage chain cam drive with
automatic tensioners,
premium gaskets and cylinder head mounted fuel injectors are a few of the
basic design features
that provide for a greatly increased engine life. The engine is designed to
operate 150,000 miles
(240,000 km) under normal conditions without part replacement other than
normal maintenance items.
A new automatic serpentine belt tensioner increases the average accessory
belt life to
100,000 miles (160,000 km).
Bob
Burlington, Ontario
'97 CC Sport, 5.2L, 3.55 auto., flame red
Gibson duals, KN drop-in
Coloured-keyed grille guard, running boards
and hard tonneau cover
Deflectors, grille insert
AR-211 15x7 rims (4.75" backspace)
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