2000 TOYOTA CAMRY engine mount

CAMRY ± NEW FEATURES36
5S-FNE ENGINE
1. Description
The 5S-FNE engine is a new engine that uses CNG (Compressed Natural Gas) as fuel, which has been devel-
oped based on the 5S-FE gasoline engine.
The main component of natural gas is methane (CH
4), which has fewer carbous (C) than gasoline (mean mo-
lecular formula: C
7.5H13.4). Therefore, the amount of CO2 discharged by this engine is approximately 70%
that of the gasoline engine. Furthermore, this engine achieves low-emission operation by precisely controlled
air-fuel ratio and using special catalysts for the CNG application.
However, because the fuel is in the gaseous form, its volumetric efficiency is low, causing lower power output
if this fuel is used in the base engine.
Therefore, the 5S-FNE engine has adopted the following features: a high compression ratio, the intake valves
with early closed timing, the intake and exhaust valves with increased lift, a low back pressure muffler made
possible by the 2-way exhaust system, injectors for gaseous fuel, and a catalytic converter designed exclu-
sively for CNG application. At the same time, precision air-fuel ratio control is effected through the use of
the air-fuel ratio sensor* and the heater oxygen sensor, thus achieving the level of performance that is equiva-
lent to the base engine. Moreover, this engine realizes extremely low emissions and restoring engine torque.
*: Already adopted on the California specification 5S-FE engine.

Specifications 
Item5S-FNE Engine5S-FE Engine
No. of Cyls. & Arrangement4-Cylinder, In-Line
Valve Mechanism16-Valve DOHC,
Belt & Gear Drive
Combustion CamberPentroof Type
ManifoldsCross-Flow
Fuel SystemSFI
Displacement cm3 (cu.in.)2164 (312.0)
Bore x Stroke mm (in.)87.0 x 91.0 (3.43 x 3.58)
Compression Ratio11.0 : 19.5 : 1
Max. Output [SAE-NET]88 kW @ 5200 rpm
(118 HP @ 5200 rpm)
101 kW @ 5200 rpm
(136 HP @ 5200 rpm)
97 kW @ 5200 rpm*
(133 HP @ 5200 rpm)*
Max. Torque [SAE-NET]178 N.m @ 2400 rpm
(131 ft-lbf @ 2400 rpm)
203 N.m @ 4400 rpm
(150 ft-lbf @ 4400 rpm)
201 N
.m @ 4400 rpm*
(148 ft-lbf @ 4400 rpm)*
IntakeOpen3 BTDC
Valve
IntakeClose38 ABDC43 ABDCValve
Timing
ExhaustOpen45 BBDCExhaustClose3 AT D C
Fuel Octane Number RON13091
Oil GradeAPI SJ EC or ILSAC
*: California Specification Models

3
CAMRY ± NEW FEATURES
167CN03 167CN02
5S-FNE Engine 5S-FE Engine39
3. Engine Proper
General
The cylinder head and the pistons have been changed for the CNG application.
Cylinder Head
Materials that excel in wear resistance have been adopted on the valve seats for both the intake and exhaust.
The shape of the holes into which the injectors mount has been changed to accommodate the injectors de-
signed exclusively for the CNG application.
The shape of water jacket around plug has been modified to prevent the deformation.
Piston
To achieve a high compression ratio, the shape of the top of the piston has been changed and pin boss hole
with taper has been adopted.
An additional surface treatment has been provided to improve heat resistance.
The material has been changed to increase rigidity.

CAMRY ± NEW FEATURES
167CN04
Valve Lifters
Intake ValveAdjusting Shims
Exhaust Valve 40
4. Valve Mechanism
Camshaft
To recover the reduction of engine performance, the intake valve timing and the amount of lift of the intake
and exhaust valves have been changed from those of the base 5S-FE engine.

Specificaitons 
Valve TimingValve Lift mm (in.)
EngineIntakeExhaustIntakeExhaustg
OpenCloseOpenCloseIntakeExhaust
5S-FNE3 BTDC38 ABDC45 BBDC3 AT D C7.9 (0.311)8.25 (0.325)
5S-FE
43 ABDC

7.7 (0.303)7.7 (0.303)
Intake and Exhaust Valves
To improve their wear resistance, the intake valves have undergone special heat treatment, and the mate-
rial of the exhaust vavles has been changed.
The shape of the stem to which the keepers attach has been changed to accommodate the adoption of the
cam with a high lift and of the inner shim type valve adjusting shims.
Valve Lifter and Adjusting Shims
TiN (titanium nitride) coated valve lifter is used to reduce the friction.
To accommodate the high lift, inner shim type valve adjusting shims are used.
Valve Spring
The valve springs for both the intake and exhaust sides accommodate the adoption of the cam with a high
lift and of the inner shim type valve adjusting shims. In addition, their spring rate has been optimized to
reduce friction.

3
CAMRY ± NEW FEATURES
172CM14
Fuel
Pressure
SensorFuel Temp.
SensorFuel
Pressure
RegulatorFuel Shutoff ValveFuel Tank
Fuel Shutoff ValveRelief Valve
Inlet Check
Valve
Fuel Temp.
Sensor
Coupler
Tank Valve Assembly
Vent Tube Manual
Shutoff
Valve Oil
Separator
Fuel Shutoff Valve Injectors
Delivery Pipe Discharge
ValveFuel
Pressure
SensorFuel
Filter43
6. Fuel System
General
The compressed gas [maximum pressure approximately 250 kg / cm
2 (3600 psi, 24.8 MPa) @ 21C
(70F)] from the CNG fuel tank located in the rear section of the vehicle is routed via a fuel filter to the
engine compartment. The pressure of the fuel is then reduced to 8 kg / cm
2 (114 psi, 785 kPa).
A pressure regulator and injectors designed exclusively for CNG application have been adopted.
A fuel pressure sensor and a fuel temperature sensor that are used for the correction of the fuel injection
volume are located on the delivery pipe.
The fuel tank, pressure regulator, and the delivery pipe are provided with shutoff valves that shut off the
fuel when the ignition switch is turned OFF.
In addition, these valves shut off the fuel when the engine stalls, the SRS airbag is deployed, or the pres-
sure in the main pipe becomes abnormally low.
A fuel temperature sensor for the fuel gauge is mounted on the tank valve assembly, and a fuel pressure
sensor is mounted immediately upstream of the pressure regulator.

Fuel System Diagram 

3
CAMRY ± NEW FEATURES
172CM17
CloseOpen45
2) Fuel Shutoff Valve for Fuel Tank
This valve uses an solenoid valve. The main pipe that supplies compressed gas to the engine is connected
to this valve, which opens when the ignition switch is turned ON. If the engine stalls, this valve automati-
cally shuts off the fuel even if the ignition switch is turned ON. The valve reopens upon restarting the
engine.
Also, this valve shuts off the fuel if the SRS airbag is deployed in a collision or if the pressure in the main
pipe becomes abnormally low.
3) Inlet Check Valve
Connected to a filler pipe that guides the fuel that fills through the coupler, the inlet check valve shuts
off by the force of a spring and by the pressure of the gas in the tank.
During filling, the pressure of the filling gas opens the inlet check valve.
4) Relief Valve
A vent tube is connected to this valve.
If the fuel tank is exposed to an abnormally high temperature, this valve opens (by melting) to discharge
the CNG at a predetermined temperature, thus helping prevent the fuel tank from bursting due to the in-
crease in gas pressure.
The discharged CNG is guided under the floor through a vent tube and is released outside of the vehicle.
Coupler
The coupler allows the fuel to be filled when it is connected with a fuel filling nozzle. The coupler has a
built-in check valve to help prevent the CNG from flowing backward.
Manual Shutoff Valve
This valve is mounted below the vehicle floor.
When servicing the vehicle, this valve can be
manually turned 90 degrees to shut off the main
pipe.

CAMRY ± NEW FEATURES
167CN10
172CM15
Fuel
Shutoff
Valve
Water Passage
Oil SeparatorRelief Valve 46
Fuel Filter
Mounted below the vehicle floor, the fuel filter
removes any moisture or oil from the fuel.
Fuel Pressure Regulator
The fuel pressure regulator regulates the fuel pressure by reducing the pressure of the compressed natural
gas from the fuel tank to the fuel injection pressure, which is 8 kg / cm
2 (114 psi, 785 kPa).
Similar to the fuel shutoff valve for the fuel tank, a fuel shutoff valve is provided on the fuel inlet side
of the fuel pressure regulator to shut off the supply of fuel when the engine is stopped or during abnormal
conditions.
An oil separator that traps the moisture and oil in the fuel is provided on the low pressure side.
A built-in relief valve is provided to protect the parts located on the low pressure side.
While the fuel pressure is being reduced by the fuel pressure regulator, the Joule-Thomson effect
associated with the expansion of the gas causes the fuel pressure regulator to be cooled excessively, exert-
ing unfavorable influence on the rubber parts such as diaphragms and fuel hoses.
Therefore, to raise the gas temperature, a water passage is provided in the fuel pressure regulator to allow
the engine coolant to warm the regulator.

3
CAMRY ± NEW FEATURES
172CM13
Discharge
ValveFuel Pressure Sensor
Fuel Temp. SensorDelivery Pipe
CNG
Fuel Shutoff
Valve
Injector
167CN23
Rubber Sheet47
Delivery Pipe
A delivery pipe with a wide passage that enables a large volume of gas to flow responsively has been
adopted to minimize the pressure loss.
A fuel pressure sensor and a fuel temperature sensor that help correct the fuel injection volume are
mounted on the delivery pipe.
Similar to the fuel shutoff valves for the fuel tank and the fuel pressure regulator, a fuel shutoff valve is
provided on the fuel inlet side of the delivery pipe to shut off the supply of fuel when the engine is stopped
or during abnormal conditions.
To discharge the fuel out of the delivery pipe during service, a discharge valve is provided.
Injector
For the injection of fuel in the gaseous state, injectors that allow the flow of a large volume of fuel and pro-
vide improved sealing performance have been adopted.

The 5S±FE engine is an in±line, 4±cylinder engine with the cylinders numbered 1±2±3±4
from the front. The crankshaft is supported by five bearings inside the crankcase. These bearings
are made of aluminum alloy.
The crankshaft is integrated with eight weights for balance. Oil holes are placed in the center of
the crankshaft to supply oil to the connecting rods, bearing, pistons and other components.
The firing order is 1±3±4±2. The cylinder head is made of aluminum alloy, with a cross flow
type intake and exhaust layout and with pent±roof type combustion chambers. The spark plugs
are located in the center of the combustion chambers.
The intake manifold has four independent long ports and utilizes the inertial supercharging effect
to improve engine torque at low and medium speeds.
Exhaust and intake valves are equipped with irregular pitch springs made of special valve spring
carbon steel which are capable of functioning no matter what the engine speed.
The intake camshaft is driven by a timing belt, and a gear on the intake camshaft engages with
a gear on the exhaust camshaft to drive it. The cam journal is supported at five places between
the valve lifters of each cylinder and on the front end of the cylinder head. Lubrication of the cam
journals and gears is accomplished by oil being supplied through the oiler port in the center of the
camshaft.
Adjustment of the valve clearance is done by means of an outer shim type system, in which valve
adjusting shims are located above the valve lifters. This permits replacement of the shims without
removal of the camshafts.
Pistons are made of high temperature±resistant aluminum alloy, and a depression is built into
the piston head to prevent interference with the valves.
Piston pins are the full±floating type, with the pins fastened to neither the piston boss nor the
connecting rods. Instead, snap rings are fitted on both ends of the pins, preventing the pins from
falling out.
The No.1 compression ring is made of steel and the No.2 compression ring is made of cast iron.
The oil ring is made of a combination of steel and stainless steel. The outer diameter of each
piston ring is slightly larger than the diameter of the piston and the flexibility of the rings allows
them to hug the cylinder walls when they are mounted on the piston. Compression rings No.1 and
No.2 work to prevent gas leakage from the cylinder and the oil ring works to scrape oil off the
cylinder walls to prevent it from entering the combustion chambers.
The cylinder block is made of cast iron. It has four cylinders which are approximately twice the
length of the piston stroke. The top of each cylinder is closed off by the cylinder head and the
lower end of the cylinders becomes the crankcase, in which the crankshaft is installed. In
addition, the cylinder block contains a water jacket, through which coolant is pumped to cool the
cylinders.
The oil pan is bolted onto the bottom of the cylinder block. The oil pan is an oil reservoir made of
pressed sheet steel. A dividing plate is included 'inside the oil pan to keep sufficient oil in the
bottom of the pan even when the vehicle is tilted. This dividing plate also prevents the oil from
making waves when the vehicle is stopped suddenly and the oil shifts away from the oil pump
suction pipe.
The 5S±FE engine uses two balance shafts. The balance shafts are fitted in balance shaft
housings that are located at the bottom of the cylinder block. The No. 1 balance shaft is driven by
the drive gear of the crankshaft No.3 counterweight at twice the speed of the crankshaft. The No.
2 balance shaft is driven by the No±1 balance shaft at the same speed in the same direction as the
crankshaft. The balance shafts are designed to eliminate secondary inertia force from the engine,
thereby reducing the engine noise (booming noise).
± 5S±FE ENGINEENGINE MECHANICALEG1±3