The purpose of the ignition system is to light the fuel/air mixture on fire at the right time.

        Three types of systems have been used in modern times:

The Breaker Point SystemThe Electronic SystemThe Computerized SystemThe Distributorless System

            We will discuss them all, but the one we will deal with in the greatest detail, is the breaker point system. The way they create the high voltage spark is the same in all types of systems, the only thing that differs is the way they are controlled.

            All ignition systems have two circuits;

The Primary Circuit

        The primary circuit is the low voltage circuit that controls the ignition system.

        The primary circuit consists of:

Battery - provides the power to run the system.Ignition Switch - allows the driver to turn the system on and

off.Ballast Resistor - reduces battery voltage from 12 volts to 9 volts.Points - a mechanical switch that acts as the triggering mechanism.Condenser - protects the points from burning out.Primary Coil - produces the magnetic field which creates the high voltage in the secondary coil.Wires - join all the components together.

The Secondary Circuit

            The secondary circuit is the circuit which converts magnetic induction into high voltage electricity to jump across the spark plug gap, firing the mixture at the right time.

            The Secondary Circuit consists of:

Secondary Coil - the part of the coil that creates the high voltage electricity.Coil Wire - a highly insulated wire, that takes the high voltage from the coil, to the distributor cap.Distributor Cap - a plastic cap which goes on top of the distributor, to hold the high tension wires in the right order.Rotor - spins around on the top of the distributor shaft, and distributes the spark to the right spark plug.Spark Plug Wires - another highly insulated wire that takes the high voltage from the cap to the plugs.Spark Plugs - take the electricity from the wires, and give it an air gap in the combustion chamber to jump across, to light the mixture.

Electrical Terms and Principles

Terms;

1. A Circuit is the continuous path that the electricity goes through. It must be complete from the source, to the switch, to the load, and back to the source again.

2. Ground is the part of the circuit which is not wires, but a part of the car's metal body. This is almost always the negative side of the battery.

3. Voltage is the electrical pressure that makes electrons move through a wire. High voltage requires lots of insulation to prevent electrons leaking to ground. An example of a high voltage circuit, is the secondary circuit. Voltage is measured

in volts. An ignition system can produce as much as 45,000 volts, a battery, 12 volts.

4. Current is the actual amount of electrons flowing. Large amounts of current require lots of copper to travel through. An example of a circuit with a large amount of current, is the cables from the battery to the starter. Current is measured in amperes, or amps for short. A starter can draw 200 amps, an ignition system, less than 5 amps.

5. Resistance is the opposition to current flow, and is measured in ohms.

6. Magnetic Field can best be described by imaginary lines of force between one pole of the magnet and the other.

                             

Principles

1. When electricity flows through a wire, a magnetic field is built up around the wire.

2. When a wire passes through magnetic lines of force, cutting them, a voltage is induced in the wire.

3. Three things are needed to produce electricity:            1. Magnetic Field            2. Circuit - a path for the electricity to go through.            3. Motion - either the wire, or the magnetic field, has to move.  

...So, How Does The Ignition System Work Anyway?        

        Electrons, supplied by the battery when the engine is starting, or by the alternator when the engine is running, are supplied to the primary circuit at about 12 volts electrical pressure. When the circuit is completed by turning on the ignition switch, and the breaker points are closed, those electrons flow through the primary coil, across the points to ground, and back to the battery again.

        When electrons flow through a wire, a magnetic field is built up around the wire. Make the wire into a coil, and the magnetic field increases by the number of loops in the coil. This magnetic field takes a relatively long period of time to build up. It isn't instantaneous. The time the coil is charging up is called coil saturation, and is controlled by the amount of time the breaker points are closed, or "dwell". the longer the points are closed for, the longer the dwell, and the stronger the magnetic field becomes.

        The coil is actually named wrong. It shouldn't be called the coil. It should be called the "coilS". The primary coil is the one that builds up the magnetic field. It has a few hundred turns of relatively large wire in it.. The secondary coil has a few thousand turns of small diameter wire in it because it is the one that will make the high voltage, but low current, and fire the spark plugs. 

        So when the points are closed and the ignition switch is turned on, a magnetic field is built up around the coil. When the points are opened by the distributor cam, electrons can no longer flow, so the magnetic field collapses toward the center of the coil at the speed of light. When it collapses, it moves through the secondary coil.  Since the secondary coil has so many turns of wire, and the speed of the magnetic field is so high, a great deal of voltage is induced into it. 

        Not all of the electrical energy is actually used though. Voltage only builds up until there is enough to ionize the air in the gap between the positive and ground electrodes of the spark plug. When there is enough voltage the spark plug fires and releases the energy to ground. It will always take between 5,000 (5KV) and 15,000 (15KV) volts to jump across the spark plug gap. If it takes more, there is too much resistance in the plug circuit, or there is too wide a spark plug gap. If it takes less than 5KV to fire the plug, there is a short, caused by a shorted plug wire, too small a spark plug gap, or a fouled plug.

        The high voltage electricity produced in the secondary coil goes from the coil tower, through the coil high tension wire to the distributor cap, from the center of the cap across the rotor to the outer terminal of the cap, through the spark plug high tension wire to the spark plug, across the plug gap to ground firing the mixture in the combustion chamber. This all takes place at the speed of light.

        The coil is actually a transformer. It transforms a twelve volts or so, into as much as 45,000 volts.

A breaker point ignition system is capable of producing between 20,000 and 30,000 volts of electrical pressure. There is very little actual current flow.Electronic ignition systems were first used as standard equipment in 1975 because of the 50,000 mile emission durability test required by the Environmental Protection Agency. The problem with the old system which had been used for seventy five years, was the points, which started to deteriorate after 1,000 miles, and were totally worn out by 20,000 miles. An electronic ignition system uses a transistor to turn on and off primary power. Transistors are electronic switches that either work or don't, they don't just deteriorate in use. Electronic systems are capable of producing up to 45,000 volts and much higher amounts of current than the breaker point system.The spark will take place just before Top Dead Center on the compression stroke.

Parts of the Primary Circuit

         Points

        The points are not anything mysterious. they are simply a mechanical switch that turns on and off the ignition coil. The are opened by the distributor cam, and closed by the point spring. When they are closed, the electricity flows from the battery to the ignition switch on the steering column, to the positive side of the primary coil, and across the points to ground. The only way the electricity can get to ground is across the points, so when the points open, electrons can no longer flow and the magnetic field around the coil collapses.

        The points are the weak link in an ignition system that includes them. After as little as 1000 miles they have deteriorated significantly, and gone out of adjustment. By 20,000 miles the engine is not likely to run at all.

        The points must be replaced, and adjusted at the time of a tune-up. They are set by adjusting "dwell, which is the number of degrees of distributor cam rotation the points are closed for. Dwell, coil saturation time, and cam angle are all the same thing.

        As you can see in the diagram, the closer the points are to being closed, the longer they stay closed for and therefore the longer Dwell is. To adjust the points, simply hook up a dwell meter to the coil. ( red lead to negative, black to engine ground) Crank the engine with the distributor cap and rotor off, and adjust the fixed contact of the points until the correct dwell reading is obtained. 

If there is a range in the dwell specification, adjust the points to the low end of the range because dwell will always increase as the rubbing block wears down.

        Condenser

        The sole purpose of the condenser is to protect the points, and keep them from burning out prematurely.

        The collapsing magnetic field not only collapses through the secondary coil, but also through the primary coil. The collapsing field induces a few hundred volts in the primary coil. These electrons have to go somewhere,  they are just trying to get to ground by the easiest means possible. If they were allowed to jump across the points, they would burn them out in as little as 100miles. They see the condenser as an easy way to ground but what it really does is store them for a fraction of a second. Meanwhile the points have opened far enough that the 300 volts or so, can't jump across them.

        The condenser is just a little can with a strip of tin foil and a strip of waxed paper, rolled together inside a little can. A wire is attached to the roll of tin foil and the waxed paper is there to separate one roll of the foil from the next one. The condenser is merely a storage room for electrons.

        Ballast Resistor (or resistor wire)

        The coil is designed to operate on 9 volts. Battery voltage (12 volts) is reduced to 9 volts by the Ballast Resistor. When the ignition switch is in the "run" position, the coil is powered through the Ballast Resistor feeding it 9 volts; but when the ignition switch is turned to "start", the Ballast Resistor gets by-passed. This feeds full battery voltage to the coil for better starting. The starter motor is drawing battery voltage down to about 10 volts at this time.

        Battery

        Don't forget, without a good battery, you don't have a good ignition system.

        Primary Coil

        The primary coil has a few hundred turns of relatively large wire. Its positive side is connected to the ballast resistor, and its negative side is connected to the distributor (or the module in an electronic system). The primary coil is the one that builds the magnetic field around it.

Parts of the Secondary Circuit

All parts of the Secondary circuit are highly insulated to prevent the high voltage electricity from escaping to ground.

        Secondary coil

        The secondary coil has a few thousand turns of hair fine wire. It is the coil that the magnetic field moves through to produce the high voltage electricity. Because of the high number of turns of wire, and because of the extremely high speed the magnetic field is moving at, ( the speed of light ) extremely high voltage is produced, but because the current flow is very small, the wire only needs to be small too. The positive side of the secondary coil attaches to the positive primary wire, and the negative side goes to the coil tower where the coil high tension wire plugs in.

        Rotor

        The rotor spins around on the top of the distributor shaft and distributes the spark from the center terminal of the cap to each insert around the outside in the firing order. Is snaps onto, or is held by screws, to the top of the distributor shaft, and only goes on one way.        The rotor is made of "Bakelite", a type of plastic. Bakelite differs from most plastics in that is is capable of withstanding a fair amount of heat. It is, however, quite brittle, but it does have high dialectic strength or resistance to current flow.        

During a tune-up, the rotor should be checked for worn electrodes, cracks, and evidence of punctures. These are places where the electricity has burned through the rotor to the distributor shaft. 

        Distributor Cap

       The distributor cap is also made of bakelite. It has brass, copper, or aluminum inserts in it to conduct the electricity to and from the rotor and the high tension wires. The cap usually has ribs on the inside to prevent flashover between the terminals. There is one insert in the center for the coil HT wire, and inserts around the outside for the spark plug HT wires. The plug wires are pushed into these terminals in the firing order.        Good quality caps have copper or brass inserts and not aluminum. There is arcing between the cap and rotor and that arcing causes oxidation of the inserts. Aluminum oxide is a very effective abrasive and causes wear on the distributor shaft bearings.        

During the tune-up, the cap should be checked for any wear on the inserts, and evidence of "carbon tracking". These are places where the electricity has made another way to ground, or one of the other terminals in the cap. Both cap and rotor should be checked during a tune-up, but they don't necessarily have to be replaced unless they show wear.

        High Tension Wires

        The HT leads are highly insulated to prevent the electricity taking a short circuit to ground. There are usually one plug wire going to each spark plug, and one coil wire going from the coil to the center of the cap, although on GM's High Energy ignition system the coil wire has been eliminated by placing the coil directly on the top of the cap.        Ht leads are usually carbon core; very much like a little piece of string impregnated with graphite. There is very rarely an actual conductor made of copper. The insulation makes up a large percentage of the diameter of the wire, and is usually made of silicon in modern wire sets.        

 During the tune-up the wires should be checked for evidence of burn through, deterioration of the wire, or boots, or any abnormality. The plug wires should be separated from each other, and never bundled together. Bundling the wires causes cross-fire between the plug leads and therefore the spark plugs. The plug wires can be checked on an engine analyzer, or oscilloscope for high or low firing lines. High firing lines indicate open circuits caused by a broken wire or spark

plug, or a wide spark plug gap. Low firing lines indicate a short , caused by leakage to ground. This could be a wire laying across an exhaust manifold or the cylinder head. If you don't have an oscilloscope, HT leads can be checked with an ohm-meter. There should be about a thousand ohms of resistance per foot of wire.When pulling plug wires off the spark plugs, twist and pull the boot, don't yank on the wire itself. This will cause the wire to break inside and although it will still work right then, it will give problems down the road as the wire burns back in both directions from the break.Wire sets don't necessarily have to be replaced during a tune-up, but they should always be checked.

Spark Plugs

        The spark plugs are the last remaining part of a modern ignition system that need servicing on a regular basis. 

        The plugs must have the correct "reach", or length of the threads, diameter, sealing method, and heat range. 

The plug on the left  requires the use of a seal ring, or gasket to prevent compression leakage past the threads. The plug on

the right does not require a gasket.

        The spark plug must run at the correct temperature. If the plug runs too hot, above 900 degrees Celsius, it will glow red hot, and the fuel mixture will start on fire all by itself, not when the plug fires. This is called pre-ignition, and must be avoided at all costs. If the plug runs too cool, below 450 degrees Celsius, it will foul up with crud because it never cleans itself. High performance and high compression engines have a great deal of heat in the combustion chamber (remember, its the heat that pushes the pistons down) and so don't require any "artificial" heat created by the plug to keep it hot. High performance engines use cold plugs. Low performance, low compression engines don't have a great deal of heat in their combustion chambers and therefore need to keep the plugs hot in another way. They use hot spark plugs.

Note the short heat path in the plug on the left. Remember, the hottest part of the plug is the center electrode. The

shorter the distance the heat has to travel to the coolant, the

cooler the plug runs. A hot spark plug has a longer insulator nose.

        Projected nose or extended tip plugs take the whole insulator and move it further out into the combustion chamber. This moves the tip into the swirling gasses in the combustion chamber and the tip keeps cleaner than a normal plug and prevents fouling.

A technician can tell a great deal about the engine he is working on simply by "reading" the spark plugs

Worn plugs, like the one on the right in the drawing above, should be replaced.

The spark plug air gap must be set when the plugs are installed. Spark plugs are not normally cleaned and re-gapped anymore. Sand blasting the insulator gives it a rough finish and it fouls up easier than when new.

Timing

        To give the maximum cylinder pressure and therefore the maximum horsepower, burning of the gasses must be finished by shortly after Top Dead Center. If the piston is allowed to go too far down the cylinder, the combustion chamber volume will have become too big, the pressure will drop and so will the power and economy.        In a breaker point ignition system, point opening triggers when the spark happens, so by changing where the points open in relation to the distributor cam, we change when the spark happens. The same thing happens in an electronic system when the transistor turns the coil off. Timing very rarely needs adjusting in an electronic system because there is nothing that goes out of adjustment. If timing is off, then someone probably adjusted it wrong last time.

        Basic or Initial Timing

        Basic timing is the starting point for the automatic timing advance systems so it is imperative that it be set correctly. 

To set the timing:

The engine must be at idle speed to make sure mechanical advance isn't operating.The vacuum line to the distributor vacuum chamber must be disconnected to make sure vacuum advance isn't operating.Basic timing is set by moving the distributor body which of course has the points attached to it. Loosen the clamp that holds the distributor down so the distributor can be moved but leave it tight enough that it can't move itself. Attach a timing light to the engine and shine it down at the timing marks. The timing light will "freeze" the timing mark on the balancer whenever #1 spark plug fires. Adjust the distributor body so the timing mark on the balancer lines up with the correct mark on the scale, and tighten down the distributor clamp. Timing marks can also be located on the engine's flywheel, especially in front wheel drive cars.

If basic , or initial timing is wrong; both vacuum and centrifugal advance will be off too.

Centrifugal Advance

Centrifugal advance affects power.

    The fuel in the combustion chamber takes approximately the same amount of time to burn no matter what speed the engine is running at for equal throttle opening. Remember that the spark only starts the fuel burning. Once we have lit it

on fire with the spark, it keeps burning all by itself, and that takes time. It takes time for the flame to travel across the cylinder. At low RPM, the piston doesn't travel very far, and therefore the spark can happen quite late; but as the engine speeds up, the piston is traveling faster, and if the spark does not happen earlier, the piston will have traveled too far down the cylinder, the volume of the cylinder will be too large, pressure will be low, and the engine will be low on power. The spark must be timed earlier to allow for the increased piston speed.

Notice that at idle, the spark fires at Top Dead Center. The piston only travels 10degrees before the fuel has finished burning.At 1000 RPM the spark fires the mixture at 8 degrees before top dead center to have the combustion complete by 10 degrees after TDC.At 2000 RPM the spark must fire at 26 degrees before TDC, to have the fuel burned by 10 degrees after TDC.

To do this, small springs hold back advance weights in the distributor, either above or below the breaker plate. As distributor speed increases, these weights are able to overcome the tension of the springs, the weights fly out, and the distributor cam, or timer core advances in relation to the distributor shaft.

Centrifugal advance can be checked very easily, and should always be checked during a tune-up. When you've got a timing light on the engine, rev it up a bit, the timing should advance as RPM increases.

Vacuum Advance

Vacuum advance affects fuel economy.

            To control the speed of a gasoline engine, a throttle, or butterfly valve is placed somewhere in the air intake system of the engine. When the throttle valve is open, the engine can take in as much air as it wants. When the throttle valve is closed, air supply to the engine is restricted, and this restriction creates a vacuum under the throttle plate called "manifold vacuum". Wide open throttle, no vacuum. Closed throttle, high vacuum. When the throttle is closed, the amount of fuel and air in the combustion chamber is much less than at wide open throttle, so the molecules of fuel are further apart. Remember, the spark only starts the fuel burning; once it starts burning, it keeps burning all by itself. If the molecules of fuel are further apart, then one has to burn for a slightly longer time before the next one starts on fire, and so on down the line. This makes a difference in the time it takes to burn the fuel. The more wide open (low vacuum) the throttle is, the less time it takes to burn. The more closed the throttle is (high vacuum), the longer the time it takes to burn.

            Ported vacuum, taken from above the throttle plate at idle, (you don't want vacuum advance at idle, it makes the engine hard to start) acts on a vacuum diaphragm, to move the breaker plate that the points are attached to. This advances the timing at part throttle for better fuel economy. 

            It is very common for vacuum diaphragms to rupture because of years of being exposed to gas fumes. This causes a sudden decrease in fuel economy.

Vacuum advance can be checked very easily, and should be checked as a part of every tune-up. You don't need a timing light or anything. With the engine idling, apply a vacuum with w vacuum pump, or by sucking on the vacuum advance line. The engine RPM should change. If it doesn't change, the vacuum advance diaphragm is ruptured and should be replaced.

           Centrifugal, and vacuum advance work together to modify the advance curve of the ignition system to maximize

fuel economy, emissions, and power.

 

See If You Understand How the Ignition System Works.

In multiple choice questions there may be more than one correct answer. Only the best one will be considered correct

What is the purpose of the ignition system ? a) to crank the engine over        b) to supply the engine with fuel to burnc) to charge the battery                d) to light the air / fuel mixture at the right time.

When should the spark take place ? a) near TDC of the exhaust stroke.    b) near TDC of the compression strokec) 25 degrees after TDC on the power stroked) after BDC

A breaker point ignition system is capable of producing how many volts? a)    20KV to 30KV                b) 35,000 volts to 45,000 volts    c)    5KV to 15KV                  d) 35,000 KV

An electronic ignition system is capable of producing how many volts? a)    20KV to 30KV                b) 35,000 volts to 45,000 volts    c)    5KV to 15KV                  d) 35,000 KV

How many volts is needed to jump across a spark plug gap? a)    20KV to 30KV                b) 35,000 volts to 45,000 volts    c)    5KV to 15KV                  d) 35,000 KV

What are the two circuits of the ignition system? a) Positive and negative        b) Battery and coilc) supply and distribution     d) Primary and secondary                   

Name the parts of the primary circuit:

Click on the correct number by the part name.Ballast Resistor     1        2        3        4        5        6       7Points                      1        2        3        4        5        6       7    Ignition Switch     1        2        3        4        5        6       7By-pass wire          1        2        3        4        5        6       7Primary coil           1        2        3        4        5        6       7Battery                    1        2        3        4          5        6       7Condenser             1        2        3        4        5        6       7

What supplies the energy to run the primary circuit? a)     Battery        b)     Coil        c)    Ignition System    d)    distributor

It supplies how many volts?a)    5KV to 15KV        b)    25,000volts        c)    9 volts        d)    12 volts

 The ballast resistor cuts this voltage down to how many volts when the engine is running?a)    5KV to 15KV        b)    25,000volts        c)    9 volts        d)    12 volts

What is drawing battery voltage down when the engine is cranking?              

a)    Battery        b)        Starter Motor        c)        ballast resistor        d)    distributor

What are the three things needed to produce electricity?a)    magnetic field, a circuit, and motionb)    battery, starter, and solenoidc)    magnetism, a circuit, and wiresd)    a circuit, motion, and radio waves

When the ignition switch is turned to " on ", and the points are closed, what is flowing  through the primary circuit?a)    magnetic field        b)    electrons        c)    ohms        d)    radio waves 

What happens around a wire whenever electricity passes through the wire?a)    magnetic field        b)    electrons        c)    ohms        d)    radio waves

What is being built up around the coil when the points are closed? a)    magnetic field        b)    electrons        c)    ohms        d)    radio waves

What happens when the points open?a)    voltage collapses                        b)    electrons are trapped    c)    magnetic field collapses            d)    coil is turned on

How fast does this happen? a)    very fast        b)    the speed of light        c)     the speed of sound        d)        100 KPH

What does this do to the secondary coil? a)    turns it on                             b)    gets it hot        c)    produces magnetic field    d)    produces a surge of electricity

What is the name for the time when the points are closed? a)    dwell        b)    cam angle        c)    coil saturation time        d) all of the above

How many windings in the primary coil? ( approximately )a)    50            b)        500        c)    5000        d)    50,000

How many windings in the secondary coil? a)    50            b)        500        c)    5000          d)    50,000

How big is the wire in the secondary coil?a)    hair fine        b)    quite small        c)    18 gauge      d)    fairly large             

What is meant by coil saturation? a)     when the ignition coil gets wet from pressure washingb)    when the coil gets too hotc)    when the coil has built up as much magnetic energy as it cand)    when the coil is left on too long

How fast does the distributor shaft turn compared to the crankshaft? a)    half as fast        b)    same speed        c)    twice as fast          d)    faster

What part does the condenser protect? a)    coil        b)    points        c)    ballast resistor        d)    battery

How does the condenser do this?a)    it speeds them up        b)    it slows them downc)    it stores them for a fraction of a secondd)    it kills them

What do the points do? a)    turn on and off the coil        b)    time when the spark happensc)    provide a path to ground for the coil        d)    all of the above

What opens the points? a)    the camshaft                          b)    the distributor cam c)    the distributor shaft           d)    a spring

 What closes the points ? a)    the camshaft                          b)    the distributor cam   c)    the distributor shaft           d)    a spring

The primary circuit always grounds through the points. Therefore the wire to the         distributor is always connected to which terminal of the coil?a)    positive        b)    negative        c)    high voltage    d)    none of the above

Dwell is the time the coil is turned   On   or  Off  ?a)    on        b)    off

What happens when the points are opened? a)    the coil is turned on and the magnetic field builds upb)    the coil is turned on, the magnetic field builds up and fires the spark plugc)    the coil is turned off, the magnetic field collapses and fires the spark plugd)    the ignition is shut off

Dwell, Coil saturation, and Cam angle, all mean the same thing.a)    True                b)       False

 Dwell is set by adjusting what  ? a)    distributor position                   b)    point gap        c)    spark plug air gap                      d)    distributor advance

Dwell should always be set before timing, because dwell affects timing, but timing doesn't affect dwell?a)    True        b)    False

What is the advantage of electronic ignition?a)    no deterioration of the spark over the life of the carb)    no points to wear outc)    timing and dwell never change due to weard)    all of the above

Rather than using a point set to turn on and off the coil, an electronic ignition system uses  what?a)    transistor        b)    reluctor        c)    pickup coil        d)    ignition switch

What are two places the ignition timing marks can be located? a)    water pump pulley and fan belt            b)    harmonic balancer and flywheelc)    cam sprocket and crank sprocket           d)    distributor and points

What tool do you use to  " Freeze " the timing marks so you can read them? a)    test lead        b)    test light        c)    dwell meter        d)    timing light

What part do you move to change the timing ?a)    distributor        b)    coil        c)    distributor cap       d)    condenser

When setting basic timing, what do you have to disconnect ?a)    centrifugal advance weights            b)    coil primary wire

c)    coil secondary wire                            d)    vacuum advance hose

When setting basic timing, how do you make sure centrifugal advance isn't in operation?a)    disconnect centrifugal advance weights        b)    make sure engine is at correct idle speedc)    set RPM to 2000                                                   d)    make sure the engine is turned off

Which of the following will not affect the amount of centrifugal advance?a)    weight and shape of advance weights         b)    tension of advance springsb)    engine vacuum                                                 d)     RPM of the engine  

In centrifugal advance, weights held in by spring tension at low RPM, fly out at high RPM and advance what to advance RPM?a)    distributor cam                    b)    breaker plate        c)    distributor shaft                  d)     distributor                                     

In vacuum advance, the vacuum diaphragm, normally held in place by a spring, is pulled at part throttle by ported vacuum and advance what to advance the timing?a)    distributor cam                    b)    breaker plate        c)    distributor shaft                  d)     distributor                                     

Vacuum advance gives you better_______a)    power        b)    emissions         c)    fuel economy        d)    all of the above

Centrifugal advance gives you better_______a)    power        b)    emissions         c)    fuel economy        d)    all of the above

If the spark plugs in an engine were too hot, it would probably:a)    knock and ping                                        b)    run on or dieselc)    wear spark plugs out prematurely        d)    all of the above

If the spark plugs in an engine were too cold, it would probably:a)    foul the plugs                                            b)    run on or diesel

c)    knock and ping                                         d)    all of the above

What type of driving would you use hot plugs  for ? a)    around town                                               b)    racingc)    highway                                                         d)    all of the above

What type of engine would you use cold plugs in ? a)    high performance                                        b)    K - carc)    tractor                                                             d)    diesel

Which plug is the cold plug? ( circle one )

                             

Name the parts of the secondary circuit:

                 

Click on the correct number by the part's name:

                      Distributor cap                     1        2        3        4        5        6                      Coil                                         1        2        3        4        5        6                      Rotor                                       1        2        3        4        5        6                      Spark Plug                             1        2        3       

4        5        6                      Coil High Tension Wire      1        2        3        4        5        6                      Spark Plug Wire                    1        2        3        4        5        6

 

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