Monday, January 21, 2008

Results of compression test:


Compression guage reading

Probable engine condition

Fails to climb during all compression strokes

Valve sticking open

20 PSI below normal

Faulty rings or valve seating

More than 20 PSI below normal

Faulty head gasket

20 PSI above normal

Excessive carbon built up in combustion chamber

1) Testing the battery:

Some maintenance free batteries do not have a charge indicator at the top. To find the state of charge measure the open circuit voltage. Measuring terminal voltage with a digital voltmeter usually makes this test. A battery with a OCV of 12.40 volts is charged enough for testing, if the voltage is less than 12.40 volts then battery needs to be charged.

Engine testing instruments:


To diagnose or to measure the performance and service of engine, requires the use of various test instruments and guages.

1) Tachometer:

The tachometer measures engine rpm; the tach may be electric, optical, or magnetic. It counts the electric pulses in the ignition system and reports the result as engine speed. This tells the driver how fast the engine crankshaft is turning. Electrical or optical tachometers are used in the shop. The electric tachometer connects to the ignition primary circuit. The teach counts the number of times per second the primary circuit opens and closes. The optical tachometer has a light beam focused on a rotating part such as engine crankshaft pulley. The teach counts how many times per second a mark on the pulley passes by.

2) Dwellmeter:

The dwellmeter elctrically measures how long the contact points remain closed during each ignition cycle of a contact point ignition system. The average of all cylinders is then displayed in degrees of distributor-cam rotation. The technician can also use the dwellmeter to set contact point gap and to check for unwanted dwell variation as engine speed increases. Excessive variation indicates mechanical trouble in the distributer. In the electronic control system, the ECM controls dwell and it is not adjustable. The dwellmeter is used to check the duty cycle of the mixture control solenoid in a feedback carburetor. A dwell tach meter is a single meter is a single meter that serves as both a dwellmeter and tachometer. This is possible because both meters have two leads and require same connections. Pushing a button or turning a knob on the meter switches the reading from rpm to dwell.

3) Cylinder compression tester:

The cylinder compression tester measures the ability of the cylinders to hold the compression while the starting motor cranks the engine. The compression tester is a pressure guage that measures the amount of pressure or compression, built up in the cylinder during the compression stroke. How well a cylinder holds compression is an indication of the condition of the piston, piston rings, cylinder wall, and valves and head gasket.

The spark plugs must be removed to use the compression tester. Before removing the spark plugs, be sure that engine is at normal operating temperature and the battery is fully charged. Use compressed air to blow out dirt or dust through spark-plug wells. Another way is to disconnect the cables, loosen spark plugs to one turn and reconnect the cables. Then start engine, run the engine for few seconds at 1000rpm. The leaking combustion gases will blow the dirt out of plug wells.

Remove the spark plugs block the throttle wide open so that the maximum amount of air enters the cylinders. Thread the compression tester adapter into spark plug hole of number 1 cylinder. Disable ignition to prevent coil damage from high voltage arcing. Disable the electric fuel pump; operate the starting motor to crank the engine through four compression strokes. The needle on the compression guage will move to show the maximum compression pressure in the cylinder.

Maruti Grand Vitara

Maruti Grand Vitara

Specificatioins:

Dimensions:

Overall length

4760mm

Overall width

1780mm

Overall height

1740mm

Wheelbase

2800mm

Front track

1500mm

Rear track

1500mm

Ground clearance

183mm

Turning radius

5.9m

Weight:

Unladen weight

1700 kgs

Laden weight

2300 kgs

Engine:

Type

4 stroke, H27A V6 24 valve MPFI

Number of cylinders

6

Piston displacement

2376cc

Bore X Stroke

88 X 75 (mm)

Compression ratio

9.5:1

Maximuim output

166bhp @6000rpm

Maximum torque

236Nm @4500rpm

Chasis:

Steering

Rack and pinion/power assisted

Brakes

Disk brakes (front), Drum brakes (rear)

Suspension front

McPherson strut

Suspension rear

5 link rigid with coil spring

Tyre size:

Tyre

235/60 R16 tubeless

Capacity:

Seating

7 persons

Fuel tank

66 liters

Maximum speed

183 kmph

Maruti Gypsy



Maruti Gypsy

Specifications:

Dimensions:

Overall length

4010mm

Overall width

1540mm

Overall height

1875mm

Wheelbase

2375mm

Front track

1300mm

Rear track

1310mm

Weight:

Kerb weight

985 kgs

Gross weight

1585 kgs

Engine:

Type

G13B MPFI 16 valve 4 stroke

Number of cylinder

4

Displacement

1298cc

Maximum power

80 bhp @ 6000rpm

Maximum torque

103Nm @4500rpm

Transmission:

Type

Manual, 5 forward, all synchromesh, 1 reverse

Transfer gearbox

Two-speed

Type

Constant mesh

Transfer gear ratio

High:1.409 Low: 2.268

Suspension:

Front and rear

Leaf spring with double action damper

Brakes:

Front

Disk brakes

Rear

Drum brakes

Tyres:

Type

F78-15-4 PR 205/70 R15

Capacities:

Fuel tank

40 liters

Engine oil

4 liters

Maruti Baleno

Maruti Baleno

Specifications:

Dimensions:

Overall length

4225mm

Overall width

1690mm

Overall height

1390mm

Wheelbase

2480mm

Front track

1440mm

Rear track

1435mm

Ground clearance

170mm

Turning radius

4.9m

Weight:

Unladen weight

985 kgs

Laden weight

1510 kgs

Engine:

Type

4 stroke, 16 valve MPFI

Number of cylinders

4 inline

Piston displacement

1599cc

Bore X Stroke

75 X 90 (mm)

Compression ratio

9.0±0.2:1

Maximuim output

91bhp @5500rpm

Maximum torque

130.5Nm @3000rpm

Transmission

Manual, 5 forward, all synchromesh, 1 reverse

Chasis:

Steering

Rack and pinion/power assisted

Brakes

Disk brakes (front), Drum brakes (rear)

Suspension front

McPherson strut

Suspension rear

McPherson strut and coil spring

Tyre size:

Tyre

165/80 R13 (LXi) 185/80 R14 (VXi) tubeless

Capacity:

Seating

5 persons

Fuel tank

51 liters

Maximum speed

175 kmph

Maruti Swift


Maruti Swift

Specifications:

Dimensions:

Overall length

3695mm

Overall width

1690mm

Overall height

1530mm

Wheelbase

2390mm

Front track

1470mm

Rear track

1480mm

Ground clearance

170mm

Turning radius

4.7m

Engine:

Type

4 stroke, 16 valve MPFI

Number of cylinders

4 inline

Piston displacement

1298cc

Bore X Stroke

74 X 75.5 (mm)

Compression ratio

9.0±0.2

Maximum power

87 bhp @6000rpm

Maximum torque

113Nm @4500rpm

Transmission

Manual, 4 forward, all synchromesh, 1 reverse

Gear ratio

(1st – 3.545) (2nd – 1.904) (3rd – 1.280)

(4th – 0.966) (5th – 0.757) (Reverse – 3.272)

Chasis:

Steering

Rack and pinion/power assisted

Brakes

Disk brakes (front), Drum brakes (rear)

Suspension front

McPherson strut

Suspension rear

Torsion beam and Coil spring

Weight:

Kerb weight

980 kgs (LXi), 1000kgs (VXi), 1010 kgs (ZXi)

Gross weight

1415 kgs

Capacity:

Seating

5 persons

Fuel tank

43 liters

Maximum speed

160kmph