The Metric System


                    EXAMPLES OF
QUANTITY            APPLICATIONS        METRIC UNIT    SYMBOL

Length              Dimensions               meter            m
                    Tire rolling
                    circumference
                    Turning circle/
                    radius
                    Braking distance

                    Greater than 999
                    meter                    kilometer        km
                    Dimensions               millimeter       mm
                    Depth of surface
                    finish                   micrometer       um

Area                Glass & Fabrics          square cm        cm?
                    Brake & Clutch      
                    linings
                    Radiator area etc.

                    Small areas              square mm        mm?

Volume              Car Luggage
                    Capacity            cubic meter           m?
                    Engine Capacity          liter            l
                    Vehicle fluid
                    capacity            cubic cm    cm?

Volume Flow         Gas & Liquid             liter per second
                                                    l/s

Time Interval       Measurement of      second           s
                    elapsed time        minute           min
                                        hour             h
                                        day              d

Velocity            General use    meter per second      m/s
                    Road speed     kilometer per hour    km/h

Acceleration &      General use    meter per second
Deceleration                       squared               m/s?



                    EXAMPLES OF
QUANTITY            APPLICATIONS        METRIC UNIT    SYMBOL

Frequency           Electronics              hertz       Hz
                                        kilohertz        kHz
                                        megahertz        mHz

Rotational          General Use         revolution per min. rpm
Speed                                   revolution per sec.   rps

Mass                Vehicle mass        megagram         t
                    Legal load rating        
                    General use         kilogram         kg
                    Small masses        gram             g
                                        milligram        mg

Density             General use         kilogram per 
                                        meter                
                                                            kg/m?
                                        gram per cubic
                                        centimeter           
                                                            g/cm?
                                        kilogram per liter   
                                                            kg/l

Force                    Pedal effort             newton      N
                    Clutch spring-force      
                    Handbrake lever
                    effort etc.

Moment of Force          Torque              newton meter     N-m
(Torque)

Power, Heat              General use              watt        W
Flow Rate           Bulbs                    kilowatt         kW

Celsius Temperature      General use    degree Celsius        °C

Thermodynamic       General use              kelvin           k
Temperature

Electric Current         General use              ampere      A
                                        milliampere           mA
                                        microampere           µA

Potential Difference          General use              kilovolt
                                                              kV
(Electromotive Force)                        volt             V
                                        millivolt           mV
                                        microvolt           µV

Electric Resistance      General use    megohm           M(insert
                                                       ohm sign) 
                                        kilohm           k(insert
                                                       ohm sign)
                                        ohm            (insert
                                                       ohm sign)




                    EXAMPLES OF
QUANTITY            APPLICATIONS        METRIC UNIT    SYMBOL

Electric Capac.     General use              farad            F
                                        microfarad            µF
                                        picofarad             pF

Fuel Consumption         Vehicle performance liter per 100
                                        kilometer        l/100 km

Oil Consumption          Vehicle performance liter per 1000
                                        kilometer        l/1000km

Stiffness           Linear stiffness         kilonewton meter
                                             kN/m

Tire Revolutions         Tire Data           revolution per
                                        kilometer        rev/km

Pressure            Tire                kilopascal            kPa
                    Coolant
                    Lubricating oil
                    Fuel pump delivery
                    Engine compression
                    Manifold
                    Brake line (hydraulic)
                    Car heating & 
                    ventilation
                    Barometric pressure

Luminous Intensity       Bulbs                    candela     cd

Accumulator              Battery             ampere hour      A-h
Storage Rating


                    U.S.A./METRIC COMPARISON

QUANTITY            USA                 METRIC         SYMBOL

Length              Inch-Foot-Mile      Meter                 m
Weight (mass)       Ounce-Pound         Kilogram         Kg
Area                Square inch/Foot    Square Meter     m?
Volume-Dry          Cubic inch/Foot          Cubic Meter      m?
      -Liquid       Ounce-Pint-Quart-Gallon  Liter            l
Velocity            Feet Per Second          MeP/Sec     m/s
Road Speed               Miles Per Hour      Km Per Hour     km/h
Force                    Pound-Force         Newton           N
Torque              Foot-Pounds              Newton meter     N-m
Power                    Horsepower          Kilowatt         kW
Pressure            Pounds Per Square Inch   Kilopascal       kPa
Temperature              Degrees Fahrenheit  Degrees Kelvin   K
                         and Celsius                         °C


                                     The AERA Technical Committee


January 1979 - SB 55 

##END##

                                              Oil Pump Replacement On 
                              MG Midget & Triumph Spitfire 1.5L Engine

Members are cautioned that when rebuilding the subject engine, care must be taken that the oil pump seats fully on the machined surface of the cylinder block.

It has been reported that some pumps were supplied without proper chamfer required to fit properly into the block.  When this condition is found, it is recommended to machine a chamfer on the edge of the oil pump body.
 
                                                                                   The AERA Technical Committee

                           Valve Crosshead To Rocker Lever Clearance On
                              NH, NT & V-1710 Series Cummins Engines

Valve crosshead nose to rocker lever clearance on the subject engines must be checked during engine rebuild and at any time valve crossheads are replaced on engines using crossheads No. 123416 & 3000326. A minimum of .020 (.51 mm) clearance must be present as illustrated in Fig. 1, on the cylinder being checked with valves completely closed and crosshead in the upmost position. After installing rocker lever assemblies, check crosshead to rocker lever clearance as follows:

1. Turn crankshaft slowly in direction of rotation until the valves are closed on the cylinder being checked. With rocker lever held firmly against the stellite pad of the crosshead, a .020 (.51 mm) wire type feeler gauge must pass between the crosshead nose and the lower beam section of the rocker lever.

2. If the feeler gauge does not pass through:

a. Remove the rocker lever and/or crosshead and grind the nose of the crosshead or 	rocker lever beam in the area circled in Fig. 1 until enough clearance is obtained.

b. If the rocker is ground, grinding should cover the complete area illustrated in Fig. 2 in a continuous arc. Do NOT grind just the contact area.

Caution: A sharp depression in this area will cause a stress riser and eventual failure of the lever. Grind only enough material to achieve the required clearance. If grinding enters the oil passage, the rocker lever must be junked.

c. Grind sharp edges smooth.




                                                                   The AERA Technical Committee