Hey,
I just got my copy of Autoworld and they had a writeup on the new 4.7.
This is probably copyrighted, so don't tell anyone you got it from me :)
Enjoy,
Graeme
'97 CC 4x4 v8
DaimlerChrysler Jeep 4.7L SOHC V-8
==================================
Good: Gobs of midrange, sounds great.
Bad: Likes the taste of unleaded.
If the DaimlerChrysler Jeep Grand Cherokee needed any help in cementing its
reputation for pleasing customers and the press, Jeep's all-new 4.7L SOHC
V-8 should seal the deal. The new 4.7L V-8 is an example of what
DaimlerChrysler powertrain engineers can accomplish when they're presented
with a clean sheet of paper (or is it blank computer screen?). David Van
Raaphorst, executive engineer-Jeep Powertrain, says the new V-8 is about as
"clean-sheet" as it gets: Only two minor components are carryover items.
"Everything is specifically designed for this engine," he asserts. That
includes all the latest in high-tech and lightweight components, such as the
hollow camshaft with sintered cam lobes, thermoplastic intake manifold and
magnesium valve covers. Going-the-extra-mile touches include chain-driven
camshafts, individual coil-on-plug ignition that eliminates the central
distributor and a neat "hybrid" cooling fan arrangement that series-
connects a typical engine-driven cooling fan with an electric in-line unit,
reducing fan noise at low engine speeds. Mr. Van Raaphorst and Robert Lee,
manager-Jeep engine engineering, stress that unlike some competing
sport/utility vehicle (SUV) V-8s, Jeep elected to stay with a cast iron
block in the interest of reliability and durability. The engine bedplate,
however, is formed from compacted graphite iron (CGI), a material that
probably is underutilized in the auto industry. "Our design criteria for
durability are important to us," says Mr. Lee of the deci- sion to use an
iron block. He reminds that Jeep's brand image is for superior off-high- way
performance, and the new 4.7L V-8 was crafted to uphold that reputation. "We
do better (than competing all-aluminum engines) in off-road, tortuous
situations," he Says. He adds that the competition has designed fine V-8s,
but that aluminum-blocked engines imply a certain scaling- down of
durability targets. Ward's testers found the Jeep 4.7L V-8's grunty 235 hp
and 295 ft.-lbs. (400 Nm) of torque, developed at a useful 3,200 rpm, to be
more than competitive with the growing wave of highly refined light-truck
V-8s. Power quickly builds with a throaty authority that almost perfectly
blurs the line between light truck and sporty passenger-car engines. The
4.7L's blend of big-engine brawn with passenger-car NVH levels fits
perfectly with the Grand Cherokee's segment-dominating role as a genteel but
rugged SUV.
We like what the new 4.7L portends for future DaimlerChrysler light trucks,
too. Mr. Van Raaphorst says the 4.7L
"absolutely" is a modular design, and sources say we can expect a range of
V-8 and V-6 engines to be borne of the 4.7L's SOHC, two-valve-per-cylinder
architecture. In fact, Chrysler officials confirmed for Ward's early last
month that a 3.7L V-6 - slated for near-term Jeep/Dodge truck applications -
will be the first variant of Jeep's startlingly refined V-8.
DAIMLERCHRYSLER JEEP 4.7L SOHC V-S Engine type: 4.7L SOHC 90' V-8
Displacement (cc): 4,701
Block/head material: iron/aluminum
Bore x stroke: 92 mm x 94 mm
Horsepower (SAE net): 235@4,800 rpm
Torque: 295 ft.-lbs. (400 Nm) @3,200 rpm Specific output: 50 hp/L
Compression ratio: 9.3:1
Application tested: Jeep Grand Cherokee
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