4.7 liter HO Engine

psithurismaccountantUrban and Civil

Nov 29, 2013 (3 years and 11 months ago)

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4.7 liter HO Engine



Introduction & History


Feature differences


Manifold / Cams kit


Manifold /
Cams part #'s


HO Intake system


HO engine Specifications


See also:

C
hrome exhaust tips









The 4.7
-
Liter HO engine


A performance enhanced "HO" version of the popular 4.7
-
Liter V8 engine made its
premier in the 2002 Grand Cherokee. The HO engine was a Grand Cherokee exclusive for
the 2002
-
2004 model years, available as an option on Limited models and standard on the
Ove
rland
-

but not available on the Laredo. For the 2004 model year, Jeep added the HO
as an option on three new special models, the
Freedom Edition
,
Columbia Edition

and the
Rocky Mountain

edition.


The performance modifications (listed in the chart below) added 30 horsepower and 30 Ft.
-
Lb. of additional torque. The HO engine is designed to run perfectly

on standard octane
fuel, but for maximum performance Jeep recommends premium fuel.


The HO engine was discontinued in the Grand Cherokee at the end of the 2004 model year.
The all
-
new 2005 model Grand Cherokee's offered the new 3.7 V6, the standard 4.7, t
he 5.7
Hemi and the new 6.1L Hemi SRT engines. Starting at the end of the 2005 model year, the
4.7 HO engine became availble in the Dodge Dakota.



Ho engine model availability
-

Grand Cherokee

Year
/
Mode
l

Lared
o


SE


Spor
t

Limite
d

Overlan
d

Freedo
m

Columbi
a

Rocky
Mtn

2001

N/A





Pilot
models









2002

N/A

N/
A

N/A

Option
al

Standard







2003

N/A





Option
al

Standard







2004

N/A

N/
A



Option
al

Standard

Optional

Optional

Option
al

2005

N/A





N/A

N/A





N/A

"N/A" = Not Available



2001
Grand Cherokee HO


What no ones realizes, and being revealed here for the first time, is that the HO engine was
originally planned for the 2001 model year. Several 2001 Grand Cherokee models were
built with the 4.7 HO engines back in 2000!


Plans for a "fu
ture" HO version of the 4.7 were put together when the new engine was
original designed for the 1999 model year, back in 1996/1997. The first HO engines were
assembled in the fall of 1999 and put into 2001 model pilot Grand Cherokee's in early
February 200
0! Twelve of these models were built, complete production versions right
down to the HO badges. Colors were Stone White, Patriot Blue, Flame Red, Sienna and
Champagne.


These special 2001 HO models also included an exclusive "Sport suspension", different
t
han that of the Up Country package. Components included exclusive springs (ZKN/ZKT
front and ZYN/ZYT rear), Goodyear P235/65R17 BSW AS/P tires, chrome tow hooks and
the skid plate package. Even more interesting is the axle ratio, which has never been used
on any other Grand Cherokee model, 3.91

!


For reasons unknown, the HO engine was held back until the 2002 model year. It's possible
that for marketing reasons Jeep wanted to introduce the HO with the new Overland model,
and to have a key option added to t
he list of new features being implemented for 2002, the
start of the second half of the WJ generation. New features for 2002 included side air bags,
adjustable pedals, the Rain Sense wiper system and the Tire Pressure Monitor System. The
HO engine was the
"icing on the cake" and turned out to be a very popular and successful
option.



Summary of HO engine feature differences


(Compared to standard 4.7 liter engine)




1. Block

-

Detonation sensor
bosses in the valley

10. Intake

-

low
-
restriction
intake system (different
resonator, air filter, air filter
hose and housing)

2. Camshaft

-

custom profile
lobes (designed for increased
performance)

11. Knock sensors

-

two, stereo

3. Connecting rods

-

modified,
with floating wrist pins (vs
pressed
-
fit pins in standard V8)

12. Main bearings

-

tri
-
metal (vs
bi
-
metal in standard V8,
designed specifically for the HO
engine)

4. Crankshaft

-

forged steel (vs
cast iron in standard V8)

13. PCM calibration
-

unique
programming

5. Crankshaft damper

-

unique
to H.O.

14. Pistons

-

dome shaped for
increased compression ratio

6. Cylinder heads

-

different
shaped combustion chambers
(for improved airflow). The
letters "H.O." are cast on the
front end of the heads
.

15. Spark plugs

-

platinum
tipped

7. Exhaust tip

-

chrome (2002
models only, decontented for
2003 models. Available only as a
one
-
piece assembly with
muffler)

16. Valves

-

unique exhaust
valves (same lift as standard
V8)

8. Fuel injectors

-

higher flow

(+3.3 lb/hr)

17. Valve springs

-

upgraded
valve springs (intake & exhaust.
Larger diameter wire and more
coils)

9. Intake manifold

-

modified
(shorter runners)





HO manifold and cams upgrade

Notes:

When the HO was first introduced in
the summer of 2001, DC service training
literature featured statements and warnings that
the upgraded parts used on the HO engine were
NOT interchangeable with the standard 4.7L
engine. So we found it interesting that l
ater on
Mopar introduced a "HO" performance cams
and manifold kit, considering that these are the
exact same parts that the factory used for the 2002 4.7L HO. The Mopar
kit includes gaskets and typically takes from 4
-
8 hours or more to install.
It is recom
mended that BOTH the manifold and the camshafts be
installed together if doing this upgrade (not just one or the other).

Quite a few Dodge truck owners have successfully installed the
manifold and cams into their standard 4.7 engines without any major
pro
blems. Most have reported horsepower gains from 5% to 15%,
varying at different RPM's. Anyone interested in doing this upgrade or
learning more about it should visit the message boards at

DodgeDakotas.com

and sea
rch through the HO related posts. Some Jeep
owners are now considering this upgrade, we'll report on the results as
info becomes available.

The Mopar Manifold/Cams kit is available from
Multitron
ics

("Kolak")


Manifold and Cams OEM Part numbers:

HO Camshafts:


Left (2002
-
2004): P/N 53021411AB

(superseded by P/N 53021411AD. MSRP: $188.00)

Right (2002
-
2004): P/N 53021412AB

(superseded by P/N 53021412AD. MSRP: $188.00)


HO Manifolds:


Note:

All manifolds are currently on national back
-
order
or discontinued (as of November 2008)

2002: P/N 53031739AC

(superseded by P/N 53031739AD. MSRP: $248.00. Used
only in HO engines for model year 2002)

2003: P/N 53013403AB

(superseded by P/N 53013403AC,
then P/N 53013403AD,
then P/N 53013403AE. MSRP: $141.00. Redesign of 2002
version, used in both standard 4.7 and 4.7 HO engines for
model year 2003)

2004: P/N 53013403AC

(superseded by P/N 53013403AD, then P/N 53013403AE.
MSRP: $141.00. Very slight non
-
pe
rformance changes
from the original 2003 version. Used in both standard 4.7
and 4.7 HO engines for model year 2004).


(NOTE: Prices listed are for reference purposes only and may vary by
dealer. MSRP prices are current as of May 2009. Parts are not
available
from this web site.)





Starting with model year 2003
production, a new manifold was
introduced and used for both the 4.7
and the 4.7 HO engines.


For more photos of the WJ manifolds, see
WJ

Manifolds




HO low restriction intake system



HO intake system components





HO manifold and throttle body


HO intake system OEM part numbers




Resonator

Quantity:
1

P/N
53013417AA

(2002)

P/N
53013417AB

(2003
-
2004)

List
price:
$
58.35


List
price:
$
66.55



Air
cleaner
hose

Quantity:
1

P/N
53013418AA

(2002
-
2004)

List
price:
$
28.75



Upper
cover

Quantity:
1

P/N
5018321AA

(2002
-
2004)

List
price:
$
71.25



Lower
cover

Quantity:
1

P/N
5018322AA

(2002
-
2004)

List
price:
$
78.25



Filter
element


Top:

9
-
5/8"
x 10
-
11/16"


Bottom:

9"
x 10
-
1/8"


Thickness:

1.5" thick


Quantity:
1

P/N
5015610AA

superseded
by

P/N
5015610AC

(2002
-
2004)

List
price:
$
24.85



Breather
tube


(Same as
standard 4.7)

Quantity:
1

P/N
53031667AC

(2002
-
2004)

List
price:
$
15.50

(All parts listed above, except for the Breather Tube, are unique to the HO
engine. Prices listed are for reference purposes only and may vary by dealer.
Prices are current as of May, 2009. Parts are not available from thi
s web
site.)




HO engine with K&N FIPK installed.

For more information of Fuel Injection Performance Kits see our
FIPK

page.




Underside view showing the WJ's muffler and catalytic converters.


4.7
HO Specifications

(see also:

WJ 4.0 / 4.7 / 4.7 HO engine specifications comparison chart

)








Dome shaped HO piston and RC7PYCB4 platinum
-
tipped
spark plug


General:


Camshaft:

Custom profile lobes (designed for increased performance)

Compression Ratio:

9:7.1

Crankshaft:

Forged steel, with custom damper

Cylinder Block:

Cast
-
iron block with modified aluminum alloy heads.
Detonation sensor bosses in the valley

Cylinder heads:

Different shaped combustion chambers (for improved
airflow)

Displacement:

4.7 Liters / 287 C.I.

Engine type:

90° SOHC V
-
8 16
-
Valve

Engine Power (SAE net):

265
-
270 BHP @ 5100 RPM

Engine Torque (SAE net):

325
-
330 LB
-
FT @ 3600 RPM

Engine Bore x stroke:

93.0 mm (3.66 in.) / 86.5mm (3.40 in.)

Firing Order:

1
-
8
-
4
-
3
-
6
-
5
-
7
-
2

Injectors:

Flow = 25.8 lb/hr @ 49psi

Knock sensors:

Two (Stereo)

Lead Cylinder:

# 1 Left Bank

Main bearings:

Tri
-
metal construction

Manifold, Intake:

Modified (shorter runners)

Oil

Capacity:

6 Quarts, 10W30 recommended

Oil pressure:

At curb idle: 04 psi min. @3000 rpm, 25
-
110 psi

RPM Engine speed, maximum:

6000 RPM

RPM Engine speed, tachometer redline:

5700 RPM

Spark plugs:

Unique platinum
-
tipped spark plugs. Type
SPRC7PYCB4, .0
40 in. gap

Throttle body size:

68mm (same as 2002
-
2004 standard 4.7 engine)


Pistons:


Piston diameter:

92.975 mm (3.6606 in.)

Piston material:

Aluminum Alloy, Symmetric pop
-
up design (for
improved compression)

Piston weight:

383.5 grams (13.52 oz.)

P
iston pins, type:

Full floating

Piston pins, clearance:

0.010
-

0.019 mm (0.0004
-

0.0008 in.)

Piston pins, diameter:

24.017
-

24.020 mm (0.9455
-

0.09456 in.)


Valves:


Valve system:

Chain
-
driven SOHC, 16 valves, hydraulic end
-
pivot
roller rockers. Uni
que exhaust valves

Valve springs (intake and exhaust):

7.30 coils, 4.77 wire diameter

Intake
-

Opens (ATDC):

3.0°

Intake
-

Closes (ATDC):

233.0°

Intake
-

Duration:

236.0°

Exhaust
-

Opens (BTDC):

235.0°

Exhaust
-

Closes (ATDC):

15.0°

Exhaust
-

Durati
on:

250.0°

Valve Overlap:

18.0°

Valve lift, Intake (at 0 lash):

12.0 mm (0.4724 in.)

Valve lift, Exhaust (at 0 lash):

10.90 mm (0.4292 in.)

Valve lift (zero lash):

Intake 12.0 mm (0.4724 in.), Exhaust 10.90 mm
(0.4292 in.)


Speed:


0
-
60 mph:

6.9 (Moto
r Trend)

0
-
62 mph:

(0
-
100 km/h): 8.3 (DCX)

1/4 mile / speed:

15.4 / 86.6 mph (Motor Trend)

Top speed (w/ limiter):

118 mph

Top speed (w/o limiter):

128 mph (DCX)


Fuel:


Fuel Economy mpg (EPA est., City/Hwy):

14/19

Fuel requirement:

Regular unleaded, 87 octane. For maximum
performance, Unleaded premium, 93 octane.




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