Valve Covers; Intake Manifold; Engine Firing Order—3.9 Liter; Water Cooled Intake Manifold - Dodge D150 1990 Service Manual

9 - 2 ENGINE
3.9L SIX-CYLINDER ENGINE
DISTRIBUTOR—CLOCKWISE ROTATION
FIRING ORDER 1-6-5-4-3-2 RN755
Fig. 2 Engine Firing Order—3.9 Liter
b u s t i o n chambers, described as "fast b u r n " . Valve
guides a n d seats are i n t e g r a l a n d machined (hard-
ened, where required) w i t h t h e cylinder head. A steel
flange composition type gasket i s used between head
a n d block. H i g h turbulence cylinder heads allow a
9:1 compression r a t i o .
V A L V E C O V E R S : The valve covers are sealed
w i t h rubber-and-cork gaskets. Gasket compression is
controlled b y t h e use o f stop-collared studs i n s t a l l e d
i n t h e cylinder heads.
I N T A K E M A N I F O L D : This i n t a k e m a n i f o l d i s a
w a t e r cooled, a l u m i n u m casting (Fig. 3). The m a n i -
fold provides for single plane air/fuel induction, ex-
h a u s t heat a n d coolant (thermostat water box)
crossover. The u n i t is also cored w i t h passages rout-
i n g " m e t e r e d " coolant flow below t h e exhaust heat
crossover a n d t h r o u g h t h e f u l l l e n g t h o f the m a n i -
fold. T h i s metered coolant flows t h r o u g h t h e r i g h t
a n d left manifold side gaskets. The sealing o f t h e
EXHAUST GAS RECIRCULATION
PASSAGES
FUEL/AIR MIXTURE PASSAGES
A
EXHAUST CROSSOVER
PASSAGE
COOLANT
PASSAGES RP116
Fig. 3 Water Cooled Intake Manifold
m a n i f o l d is accomplished b y steel embossed side gas-
kets w i t h front and rear molded gaskets. T h e i n t a k e
m a n i f o l d is also cored w i t h upper level E G R passages
for balanced (cylinder to cylinder) E G R d i s t r i b u t i o n .
V A L V E T R A I N : Valve t r a i n has h y d r a u l i c r o l l e r
lifters and exhaust valve rotators. Rocker arms are
e i t h e r r i g h t or left, a n d i n s t a l l e d on a rocker a r m
shaft attached t o the cylinder head. V i t o n valve stem
seals provide positive i n t a k e valve sealing. C u p
shields are installed on exhaust valve stems. Conven-
t i o n a l types o f push rods, springs, retainers a n d
valve stem locks are used.
E X H A U S T M A N I F O L D S : E x h a u s t manifolds are
" l o g " type w i t h rear exits t h a t a t t a c h d i r e c t l y t o t h e
cylinder heads. B o t h manifolds provide for a i r injec-
t i o n , w h i l e t h e r i g h t m a n i f o l d incorporates a heat
control valve.
The 3.9L engine description is listed below (Fig. 4):
T y p e . . . 90°V-6
Bore and Stroke 99.3 x 84.0 mm (3.91 x 3.31 inch)
Displacement 3.9 Liters (238 cubic inch)
Compression Ratio 9.0:1
Engine Torque 265 N-m (195 ft-lbs) @ 2,000 rpm
Firing Order 1-6-5-4-3-2
Lubrication . . . . Pressure Feed—Full Flow Filtration
Engine Oil Capacity 3.8 Liters (4 Quarts)
Cooling System . . . . Liquid Cooled—Forced Circulation
Cooling System Capacity 13.2-13.5 Liters (14-14.3 Quarts)
Cylinder Block Cast Iron
Crankshaft Nodular Iron
Cylinder Head . . . . . . . . . . . . . . . . . . . Cast Iron
Combustion Chambers "Fast Burn" Design
Camshaft . . . . . . . . . . . . . Cast Iron
Pistons Aluminum Alloy with Strut
Connecting Rods Forged Steel
Fig. 4 Engine Description—3.9 Liter
J9009-94