PracticeVideosBlogFlashcardsEspañol
All Practice Exams

100+ Free Motor Mechanic Trade Test Practice Questions

South Africa Artisan Trade Test - Motor Mechanic (Petrol) practice questions are available now; exam metadata is being verified.

✓ No registration✓ No credit card✓ No hidden fees✓ Start practicing immediately
100+ Questions
100% Free

Loading practice questions...

Same family resources

Explore More South Africa Artisan Trade Tests

Continue into nearby exams from the same family. Each card keeps practice questions, study guides, flashcards, videos, and articles in one place.

South Africa Artisan Trade Test — Boilermaker

Practice Questions

South Africa Artisan Trade Test — Bricklayer

Practice Questions

South Africa Artisan Trade Test — Carpenter

Practice Questions

South Africa Artisan Trade Test — Diesel Mechanic

Practice Questions

South Africa Artisan Trade Test — Electrician

Practice Questions

South Africa Artisan Trade Test — Fitter

Practice Questions
2026 Statistics

Key Facts: Motor Mechanic Trade Test Exam

100

Practice Questions

OpenExamPrep

2-3 days

Trade Test Duration

QCTO

60%

Typical Pass Mark

QCTO

QCTO/NAMB

Administered By

QCTO

Petrol

Spark-Ignition Trade

OpenExamPrep

14.7:1

Stoichiometric Air-Fuel Ratio

Trade theory

The Motor Mechanic artisan trade test is South Africa's national assessment for qualifying as a petrol motor mechanic, administered through the QCTO and NAMB framework. It is a competence-based trade test of written and practical tasks conducted over two to three days at a QCTO-accredited trade test centre by a NAMB-registered assessor, and access is commonly gained through an N2 certificate with relevant trade-theory subjects plus workplace experience or an RPL route. The trade theory covers petrol engine theory, fuel/ignition and EFI systems, transmission and driveline, brakes/steering/suspension, electrical and electronics, diagnostics, and safety, using South African terminology. This free prep includes 100 research-based practice questions with explanations and an AI tutor.

Sample Motor Mechanic Trade Test Practice Questions

Try these sample questions to test your Motor Mechanic Trade Test exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1In a four-stroke petrol engine, in what order do the four strokes occur during one complete cycle?
A.Compression, induction, power, exhaust
B.Induction, compression, power, exhaust
C.Power, exhaust, induction, compression
D.Induction, power, compression, exhaust
Explanation: A four-stroke petrol (Otto-cycle) engine completes induction (intake), compression, power (combustion/expansion), and exhaust in that sequence over two crankshaft revolutions. Fuel-air mixture is drawn in, compressed, ignited to produce power, then burnt gases are expelled.
2How many crankshaft revolutions are required to complete one full cycle of a four-stroke petrol engine?
A.One revolution
B.Two revolutions
C.Three revolutions
D.Four revolutions
Explanation: A four-stroke engine needs two complete crankshaft revolutions (720 degrees) to complete one cycle, because each stroke corresponds to half a crankshaft turn and there are four strokes. This is why the camshaft turns at half crankshaft speed.
3The camshaft of a four-stroke engine rotates at what speed relative to the crankshaft?
A.The same speed as the crankshaft
B.Twice crankshaft speed
C.Half crankshaft speed
D.Quarter crankshaft speed
Explanation: Because each valve opens once every two crankshaft revolutions, the camshaft must rotate at half engine (crankshaft) speed. The timing gears or belt are therefore geared 2:1, with the camshaft sprocket having twice as many teeth as the crankshaft sprocket.
4Compression ratio of a petrol engine is best defined as the ratio of the cylinder volume when the piston is at:
A.BDC to the volume at TDC
B.TDC to the volume at BDC
C.Mid-stroke to the volume at TDC
D.BDC to the swept volume only
Explanation: Compression ratio = total cylinder volume with the piston at bottom dead centre (swept + clearance volume) divided by the clearance volume with the piston at top dead centre. Typical petrol engines run around 9:1 to 11:1, lower than diesels to avoid detonation.
5On which stroke does the spark plug ignite the air-fuel mixture in a petrol engine?
A.Near the end of the induction stroke
B.Near the end of the compression stroke
C.At the start of the exhaust stroke
D.In the middle of the power stroke
Explanation: The spark occurs just before the piston reaches TDC at the end of the compression stroke (ignition advance), so peak combustion pressure develops shortly after TDC to drive the power stroke. Igniting the fully compressed charge maximises efficiency and power.
6The most common firing order for a four-cylinder in-line petrol engine is:
A.1-2-3-4
B.1-3-4-2
C.1-4-2-3
D.1-2-4-3
Explanation: The firing order 1-3-4-2 is the most widely used for in-line four-cylinder engines because it spreads the power impulses evenly and balances the loading on the crankshaft, reducing vibration. 1-2-4-3 is also used on some engines but 1-3-4-2 is the classic.
7The clearance between the rocker/cam and the valve stem when the valve is fully closed is called the:
A.Valve overlap
B.Valve clearance (tappet clearance)
C.Valve lift
D.Valve lead
Explanation: Valve (tappet) clearance is the small gap left in the valve train when the valve is closed to allow for thermal expansion of the components as the engine heats up. Too little clearance can hold valves open and burn them; too much causes noisy operation and reduced lift.
8Valve overlap is the period during which:
A.Both the inlet and exhaust valves are open at the same time near TDC
B.Both valves are closed during compression
C.The inlet valve opens before the exhaust closes near BDC
D.The exhaust valve stays open during the whole power stroke
Explanation: Valve overlap occurs near the end of the exhaust and start of the induction stroke (around TDC) when both the inlet and exhaust valves are open simultaneously. It uses the momentum of the exhaust gas to help draw in fresh charge, improving cylinder filling (scavenging).
9Pre-ignition in a petrol engine is best described as:
A.Ignition of the charge by a hot spot before the spark occurs
B.The spark occurring exactly at TDC
C.Detonation after the spark caused by low octane fuel
D.Failure of the spark plug to fire at all
Explanation: Pre-ignition is uncontrolled combustion that starts before the spark, caused by a hot spot such as glowing carbon, an overheated spark plug, or sharp edges in the chamber. It raises pressures and temperatures abnormally and can quickly damage pistons.
10Detonation (knocking) in a petrol engine is most likely to be reduced by:
A.Using a lower octane fuel
B.Increasing the compression ratio
C.Using a higher octane fuel
D.Advancing the ignition timing further
Explanation: Detonation is the spontaneous explosion of the remaining end-gas after the spark, producing a metallic knock. A higher octane fuel resists auto-ignition, so it reduces or eliminates knock. Retarding timing and lowering compression also help.

About the Motor Mechanic Trade Test Practice Questions

Verified exam format metadata for South Africa Artisan Trade Test - Motor Mechanic (Petrol) is pending. The practice questions above remain available while official exam length, timing, passing score, fee, and administrator details are reviewed.