Diesel Mechanic Questions & Answers

What are the duties & responsibilities of a Diesel Mechanic ?

1) Repairs, maintains, and installs oil well drilling machinery and equipment, using hand tools and following oral and written work orders: Attaches hoisting cables to pumps, transmissions, diesel engines, and other equipment at drill sites, lashes equipment to trucks for transfer to repair yard, and guides lowering of equipment onto blocks in or near repair shop.

 2) Disassembles engines and mechanical units, using hand and power wrenches, screwdrivers, and other handtools.

 3) Cleans parts, such as pistons, valves, and parts of transmissions and clutches, using steam hose and detergents.

 4) Inspects parts for defects.

 5) Installs specified new or reconditioned parts, such as relined brake bands and clutch plates, sprockets, pump cylinders, and other parts of engines and mud pumps.

 6) Reassembles complete units.

 7) Tests function of pumps and other mechanical units, using auxiliary power.

 8) Test-runs engines at various speeds and observes efficiency of operations.

 9) Welds broken structures, such as engine mounts, hand rails, machine guards, and pipe racks, using electric and acetylene welding equipment.

 10) Paints reconditioned units, using spray gun.

 11) Installs repaired equipment at drill sites, observes operations, and readjusts components, as necessary.

 12) May maintain, repair, and install machinery and equipment at drill sites and be designated Field Mechanic.

How do diesel injection pumps work?

An Injection Pump is the device that pumps diesel (as the fuel) into the cylinders of a diesel engine. ... It rotates at half crankshaft speed in a conventional four-strokediesel engine. Its timing is such that the fuel is injected only very slightly before top dead centre of that cylinder's compression stroke.

What Is Automatic Valve?

Answer :

A valve assisted by a spring,'which is opened by a difference of pressure acting in one direction and closed by a difference in pressure acting in the opposite direction.

What Is Case-harden?

Answer :

To harden the outer surface of metal to a given case or shell depth, while leaving the inner portion soft to absorb shocks and allow bending.

What Is Analog Sensor?

Answer :

A sensor which sends a range of voltages in DC to the ECM to describe, for example, coolant temperature, engine oil pressure, or atmospheric pressure.

What Is Air Signal Attenuator?

Answer :

A device that reduces both exhaust smoke and noise by slowing engine acceleration slightly until adequate turbocharger boost pressure is present.

 What Is Critical Speeds?

Answer :

Speeds at which the frequency of the power strokes synchronize with the crankshaft's natural frequency. If the engine is operated at one of its critical speeds for any length of time, a broken crankshaft may result.

What Is Brake Thermal Efficiency?

Answer :

Ratio of power output in the form of brake horsepower to equivalent power input in the form of heat from fuel. Typical brake thermal effidency ranges from thirty to forty-two percent.

Tell Me What Are Different Types Of Vehicles Based On Diesel Engines?

Answer :

Automobiles, trucks, buses, marines, and construction areas are popular types that are based on diesel engines.

Do You Know What Is Cam?

Answer :

A rotating component of irregular shape. It is used to change the direction of the motion of another part moving against it, e.g., rotary into reciprocating or variable motion.

What Is Dead Center?

Answer :

Either of the two positions when the crank and connecting rod are in a straight line at the end of the stroke. The total piston travel is the distance between the two dead center positions.

What Is Relay?

Answer :

Normally used in control circuits, relay is a switch driven by electricity and rules over contactor by virtue of low amperage contacts.

What Is Compression Release?

Answer :

A device which holds open the intake or exhaust valve, thereby permitting the engine to be turned over without compression. This is one method of engine braking where by the power stroke is cancelled.

What Is Chamfer (taper Lead)?

Answer :

The taper at the thread end of a tap or the throat of a die, made by cutting away the crests of the first few threads. This distributes the work of cutting over several threads and acts as a guide in starting the tap or die. The chamfer is relieved to facilitate cutting.

What Is Constant-pressure Combustion?

Answer :

Combustion which occurs without change in pressure. In an engine, this is obtained by a slower rate of burning than with constant volume combustion.

What Is Bimetal Arm?

Answer :

A thin sandwich strip of two metals with very dif- ferent heat expansion rates that bends to the left or the right due to heat caused by resistance to voltage.

Explain Me Diesel Mechanic Duties For In This Matter?

Answer :

Diesel mechanic is typically responsible to operate, handle, maintain and repair diesel engines that are used to run any machinery including vehicles, generators and other machinery.

What Is Brush?

Answer :

This graphite or copper made conducting element maintains sliding electrical contact between static and moving element.

 What Is Condenser?

Answer :

Also called a capaciator, this electronic component CI stores up electric charge until a set svoltage is reached; then a high but rapidly decaying current flows through the circuit until finally the voltage difference between the two leads reaches zero.

What Is Atmospheric Pressure (barometric Pressure)?

Answer :

The pressure exerted by the atmosphere, averaging 14.7 psi at sea level with a decrease of approximately 1/4 lb per 1,000 ft of altitude gained.

Please Explain What A Diesel Mechanic Is Responsible For?

Answer :

Diesel mechanics are basically responsible for the troubleshooting, upkeep, maintenance, and repair of diesel engines. This may include vehicle engines, generators and plant machinery that requires diesel to make it run.

What Is Generator?

Answer :

A utility device that converts mechanical energy into electrical energy, available either in the form of direct or alternating current.

What Is Displacement?

Answer :

In a single acting engine, the volume swept by all pistons in making one stroke each. The displacement on one cylinder in cubic inches is the circular area (in square inches) times the stroke (in inches).

What Is Critical Compression Ratio?

Answer :

Lowest compression ratio at which any particular fuel will ignite by compression. The lower the critical compression ratio the better ignition qualities the fuel has. (Gasoline engine, 4:1; oil engine, 7:1; diesel engine, 12.5:1.)

What Is Brinen Hardness?

Answer :

The surface hardness of a metal, alloy, or similar material according to l.A. Brinell's method of measurement. A metal's surface is struck at a given force by a rigid steel ball of a given diameter, and the indentation is measured.

Do You Know What Are Two Most Essential Skills That A Diesel Mechanic Should Own?

Answer :

A diesel mechanic must employ two important skills. First is analytical mind to be able to evaluate any issue occurred in the engine. Second is ability to read and perceive instructions manuals and blueprints of the engines since each engine has different design and small engine routes can end up in complex issues.

Question 25. What Is Dynamo?

Answer :

A mechanical device that converts mechanical energy into electrical energy through electromagnetic induction process.

What Is Battery Charge Rectifier?

Answer :

This component changes AC voltage from the battery charge windings to DC voltage for charging a battery.

Tell Me What Is Alternating Current (ac)?

Answer :

Current flowing from zero to a positive maximum and then back to zero, flows down again to a negative maximum to return back to zero.

What Is Load?

Answer :

Load is that the amount of electric power used by devices associated to electricity generating system.

What Is Brake Mean Effective Pressure (bmep)?

Answer :

Mean effective pressure acting on the piston which would result in the given brake horsepower output, if there were no losses due to friction, cooling, and exhaustion. Equal to mean indicated pressure times mechanical effidency.

As You Know Diesel Mechanics Are Typically Assigned Based On Their Personal Skills In Specific Fields. What Fields Are You Most Adaptable Working In?

Answer :

Whilst I am an experienced and skilled mechanic with comprehension in diesel engine handling with their wholeness, I am sure my interest is about maintaining electrical and system of brake related to vehicular engines.

What Is Ampere-hour Capacity (ah)?

Answer :

A measurement of the battery's capacity to deliver a specified current over a spec.ified length of time.

Tell Me What Relevant Skills Do You Possess?

Answer :

Apart from technical aptitude and in-depth knowledge of working on complex and varied diesel engines, I also possess strong leadership skills, especially where crew management is concerned. Moreover, I can use modern technologies and hand tools to manage maintenance and repair work.

What Is Rated Voltage?

Answer :

The specific voltage measurement at which an engine generator set can start functioning.

What Is Winding?

Answer :

Winding comprises all the coils of a generator.

What Is Off-peak Rate?

Answer :

This is the rate of cost for power used during Off-Peak periods.

What Is Stator?

Answer :

Stator is the static or unmovable element of a generator.

Tell Me What Does A Typical Diesel Engine Reconditioning Procedure Consist Of?

Answer :

The reconditioning process includes repairing or replacing pistons, bearings, gears, valves, and bushings. The use of engine lathes and boring machines is an important part of the reconditioning procedure.

What Is Cradle?

Answer :

Covering a generator or engine, this metal frame provides extra protection from outer disturbances.

What Is Gensets?

Answer :

A handy power generator, converting fuel into electrical power through mechanical ways. Clip-on gensets and Underslung gensets are most popular.

What Is Electronic Engine Control (eec)?

Answer :

Microcomputer coupled with sensors and controls for fuel, coolant, and other on board systems, as well as self diagnostic ability.

What Is Air Pollution?

Answer :

Contamination of the earth's atmosphere by pollutants such as smoke, harmful gases, etc.

What Is Ignition Coil?

Answer :

Ignition coil supplies DC voltage to the spark plugs.

 What Is Motor Generator?

Answer :

Normally used either to regulate or condition power from a raw power source like electric utility grid.

Tell Us What Do You Believe Are The Two Most Important Skills That A Diesel Mechanic Should Have?

Answer :

While working as a diesel mechanic is skilled work entirely, the 2 most important things are to have an analytic mind and the ability to read and understand blueprints and instruction manuals. That is is because each engine is different and it is the small intricacies in their make-up that end up in complicated problems or maintenance issues.

What Is Rotor?

Answer :

Rotor is the element that on, which the rotating of a generator depends.

What Is Off-peak?

Answer :

A specific period when power demand of a system is comparatively low. Counted from 10 p.m. until 6 a.m., from Monday through Saturday and during the whole day on Sunday by NERC.

What Is Flywheel?

Answer :

Storing energy in a rotating mass form, Flywheel is a very active substitution of chemical batteries.

What Is Diesel Generator?

Answer :

Starts up and generates power automatically during power cut.

What Is Current?

Answer :

The flow of particles charged by electricity.

Explain Me What Additional Qualifications Do You Have That You Feel Have Made You A Successful Diesel Mechanic?

Answer :

I have deep knowledge of tooling, supply management, and inspection tools. These along with an exceptional attention to detail and thoroughness of nature make it possible for me to work for extended hours especially when detailed troubleshooting or maintenance is needed.

Do You Know What Is Phase?

Answer :

Phase measures the uniform periodic change in amplitude or magnitude of an alternating current.

What Is Rectifier?

Answer :

Rectifier is used for converting alternating current (AC) to direct current (DC).

What Is Standby Generator?

Answer :

Used for power backup in home, Standby Generator is driven by gasoline or LP gas.

What Is Engine Generator?

Answer :

Generates electric power with the help of natural gas or diesel reciprocating engine.

What Is Distribution?

Answer :

Supply of lower voltage electric power from a centralized substation to the point of end use.

What Is Contactor?

Answer :

It is used in control circuits.

Please Explain What Three Duties Do You Consider “all In A Day's Work” For Someone Working In A Diesel Mechanic Position?

Answer :

The first most important duty of a diesel mechanic is performing routine maintenance on diesel engines. Secondly, diesel mechanics replace and repair damaged or malfunctioning parts in engines, followed by fixing brake and electrical systems.

What Is Stator Winding?

Answer :

Comprises of stator coils with their interconnections.

What Is Core?

Answer :

Core is the magnetic structure built lamination in the generator.

What Is Electric Generator?

Answer :

Generates electricity from a source of mechanical energy.

Do You Know What Is Direct Current (dc)?

Answer :

Current produced by storage battery or electromagnetic induction, with a unidirectional flow.

What Is Blackout?

Answer :

Sudden disruption of electrical power.

What Is Cylinder Head?

Answer :

The replaceable portion of the engine that seals the cylinder at the top. It often contains the valves, and in some cases, it is part of the combustion chamber.

What Is Bendix Type Starter Drive (inertia Starter Drive)?

Answer :

A type of starter drive that causes the gear to engage when the armature starts rotating and to automatically disengage when it stops.

Tell Us What Abilities Do You Own That You Feel You Can Be Good Diesel Mechanic?

Answer :

I have comprehensive knowledge of equipment, supply handling and inspection instruments. These together with an attentive to detail and meticulousness make it likely for me to work overtime specifically when sharp maintenance or troubleshooting is necessary.

What Is Peak?

Answer :

Measurement of the maximum load that is consumed within a specified time period.

What Is Magneto?

Answer :

Built with permanent magnets, Magneto is a special kind of alternator that generates current for ignition in an internal combustion engine.

What Is Turbine Generator?

Answer :

Running on gas or steam turbine, turbine generator generates electricity through electromagnetic forces caused by steam, water or wind etc.

What Is Backup Generators?

Answer :

Used for fulfilling emergency load requirement during sudden shortage of power.

 What Is An American Public Power Association (appa)?

Answer :

A national service organization that represents 2000 municipal and other state or local publicly owned electric utilities spread across the United States.

 What Is Combustion Cycle?

Answer :

A series of thermodynamic processes throughwhich the working gas passes to produce one power stroke. The full cycle is: intake, compression, power, exhaust.

What Is Digital Sensor?

Answer :

A sensor which uses duty cycles of two voltages in timed pulses of AC to relay such information as speed, throttle position, and engine timing.

What Is Cam-ground Piston?

Answer :

Oval shaped piston head design used by most large-diameter aluminum pistons, which expands in a nonuniform manner when hot to attain a round shape.

 What Is Absolute Temperature?

Answer :

The temperature measured using absolute zero as a reference. Absolute zero is -469.69° F (-273.16° C) and is the lowest point of temperature known.

As You Know Diesel Mechanics Are Usually Hired Depending On Their Expertise In Specific Areas. What Areas Are You Most Comfortable Working In?

Answer :

While I am an experienced diesel mechanic and have experience in handling diesel engines in their entirety, I believe my interest lies in handling electrical systems and overhauling pertaining to vehicular diesel engines.

What Is Kva?

Answer :

KVA is kilovolt-ampere and is the unit of apparent power. KVA is used for measuring the power consumption of non-resistive equipment such as motors, computers, and most non-incandescent lighting.

What Is Voltage Regulator?

Answer :

By modulating the flow of DC to the rotor, Voltage regulator maintains optimum generator voltage, automatically.

What Is Non-utility Generator?

Answer :

Connected to an electric utility system, Non-utility Generator generates electricity specifically for those not owned by an electric utility.

What Is Diesel Engine?

Answer :

An internal combustion engine in which fuel oil is burnt by heat produced from air compression. The most commonly bought Industrial Diesel Engines are either Rebuilt Diesel Engine or Used Diesel Engine.

What are the different types of diesel fuel injection systems?

There are four main types of mechanical diesel injection systems:

Inline or rotary distributor pump.

Individual control pump.

Common rail.

Unit injection. The inline or rotary distributor pump is one of the most common types of diesel injection found.

What is the function of injector in diesel engine?

Pump elements such as the cylinder and plunger are built into the injection pumpbody. The fuel is compressed to high pressure when the cam lifts the plunger, and is then sent to the injector. In diesel engines the intake of air is almost constant, irrespective of the rotating speed and load.

Can diesel injectors be cleaned?

The Importance of Cleaning Diesel Injectors. If the fuel injectors have deposits, it's important to clean them to restore engine performance back to the way it was. ... And no injector cleaner or fuel additive is going to be able to fix a worn injector.

Do diesels have fuel pumps?

The injection pump does the job of both the throttle and the ignition system needed in gasoline engines. When troubleshooting a gasoline engine, you check compression, fuel, and spark. A diesel doesn't have an ignition system, so there is one less thing to go wrong with it

What are the symptoms of a bad diesel fuel injector?

Fuel injector symptoms for bad, faulty, dirty, clogged, or leaking injectors are :

Starting issues.

Poor idle.

Failed emissions.

Poor Performance.

Engine does not reach full RPM.

Increased fuel consumption.

Rough engine performance.

Surging and bucking under various throttle loads.




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