SOS Mechanic Certificate -Engine Repair
Exams Practice 2025-2026
1. WHICH OF THE FOLLOWING IS TRUE ABOUT ADJUSTING VALVE TAPPET
CLEARANCE: VALVE TAPPET CLEARANCE SHOULD BE ADJUSTED AT TDC AT
THE END OF THE COMPRESSION STROKE.
2. THE HYDRAULIC LIFTERS ARE NOISY AT HIGHWAY SPEEDS BUT QUIET
AT LOW SPEEDS. WHAT SHOULD YOU DO FIRST AS YOU DIAGNOSE THIS
PROBLEM?: CHECK CRANKCASE OIL LEVEL.
3. THE VALVE TIMING ON MOST ENGINES IS CONTROLLED BY:: A BELT,
CHAIN OR GEAR DRIVE
4. THE BEARING INSERTS BELOW HAVE BEEN PLASTIGAGED. WHAT CAN
YOU DETERMINE ABOUT THESE PICTURES?: INSERT"A" HAS MORE CLEAR-
ANCE.
5. THE COMPRESSION TEST HAS SHOWED THAT THE MIDDLE TWO CYLIN-
DERS ON ONE SIDE OF A V-8 ENGINE HAD READINGS OF 50 PSI. THE OTHER
CYLINDERS HAD READINGS BETWEEN 135 PSI AND 140 PSI. WHAT IS THE
LIKELY CAUSE OF THIS CONDITION?: A BLOWN HEAD GASKET.
6. EXCESSIVELY WORN VALVE GUIDES:: ALL OF THE ABOVE.
7. INTAKE VALVE DEPOSITS, AS SHOWN BELOW:: BOTH B AND C
8. WHAT IS BEING CHECKED ON THE VALVE SPRING IN THE ILLUSTRATION
BELOW?: INSTALLED HEIGHT
9. YOU ARE USING A VACUUM GAUGE CONNECTED TO THE INTAKE MANI-
FOLD. WHICH OF THE FOLLOWING IS TRUE?: WHEN THE ENGINE IS RAPIDLY
ACCELERATED, THE NEEDLE WILL RISE TO A HIGH READING.
10. WHAT ARE THE MINIMUM AND MAXIMUM MEASUREMENTS OF A SHAFT
GIVEN 2.125 PLUS OR MINIUS .015?: 2.062-2.250
11. THE MECHANIC HAS DETERMINED THAT NO FUEL SQUIRTS INTO THE
CARBURETOT WHEN THE THROTTLE IS OPENED QUICKLY. WHAT COULD BE
CAUSED BY:: ALL OF THE ABOVE.
12. A WARM ENGINE HAS LOW OIL PRESSURE. THE MOST LIKELY CAUSE OF
THE LOW OIL PRESSURE IS:: LEAKY MAIN BEARING SEALS
13. WHAT IS THE READING OF THE 0-1 INCH MICROMETER BELOW?: 5.750"
wrong 1.599 is prob right answer
14. YOU ARE REINSTALLING PISTONS WITH NEW RINGS. THE RING COM-
PRESSOR WILL NOT FIT TIGHT AROUND A PISTON SKIRT AND THE RINGS
BIND ON THE BLOCK SURFACE. WHAT SHOULD YOU DO?: CHECK THE RING
END GAP.
15. YOU HAVE CHECKED THE CRANKSHAFT AND FOUND THYE FOLLOWING
MEASUREMENTS BELOW. THE ROD JOURNAL SURFACES ARE SMOOTH
AND NO ROD JOURNAL TAPER IS PRESENT. WHAT SHOULD YOU DO?
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Exams Practice 2025-2026
1. WHICH OF THE FOLLOWING IS TRUE ABOUT ADJUSTING VALVE TAPPET
CLEARANCE: VALVE TAPPET CLEARANCE SHOULD BE ADJUSTED AT TDC AT
THE END OF THE COMPRESSION STROKE.
2. THE HYDRAULIC LIFTERS ARE NOISY AT HIGHWAY SPEEDS BUT QUIET
AT LOW SPEEDS. WHAT SHOULD YOU DO FIRST AS YOU DIAGNOSE THIS
PROBLEM?: CHECK CRANKCASE OIL LEVEL.
3. THE VALVE TIMING ON MOST ENGINES IS CONTROLLED BY:: A BELT,
CHAIN OR GEAR DRIVE
4. THE BEARING INSERTS BELOW HAVE BEEN PLASTIGAGED. WHAT CAN
YOU DETERMINE ABOUT THESE PICTURES?: INSERT"A" HAS MORE CLEAR-
ANCE.
5. THE COMPRESSION TEST HAS SHOWED THAT THE MIDDLE TWO CYLIN-
DERS ON ONE SIDE OF A V-8 ENGINE HAD READINGS OF 50 PSI. THE OTHER
CYLINDERS HAD READINGS BETWEEN 135 PSI AND 140 PSI. WHAT IS THE
LIKELY CAUSE OF THIS CONDITION?: A BLOWN HEAD GASKET.
6. EXCESSIVELY WORN VALVE GUIDES:: ALL OF THE ABOVE.
7. INTAKE VALVE DEPOSITS, AS SHOWN BELOW:: BOTH B AND C
8. WHAT IS BEING CHECKED ON THE VALVE SPRING IN THE ILLUSTRATION
BELOW?: INSTALLED HEIGHT
9. YOU ARE USING A VACUUM GAUGE CONNECTED TO THE INTAKE MANI-
FOLD. WHICH OF THE FOLLOWING IS TRUE?: WHEN THE ENGINE IS RAPIDLY
ACCELERATED, THE NEEDLE WILL RISE TO A HIGH READING.
10. WHAT ARE THE MINIMUM AND MAXIMUM MEASUREMENTS OF A SHAFT
GIVEN 2.125 PLUS OR MINIUS .015?: 2.062-2.250
11. THE MECHANIC HAS DETERMINED THAT NO FUEL SQUIRTS INTO THE
CARBURETOT WHEN THE THROTTLE IS OPENED QUICKLY. WHAT COULD BE
CAUSED BY:: ALL OF THE ABOVE.
12. A WARM ENGINE HAS LOW OIL PRESSURE. THE MOST LIKELY CAUSE OF
THE LOW OIL PRESSURE IS:: LEAKY MAIN BEARING SEALS
13. WHAT IS THE READING OF THE 0-1 INCH MICROMETER BELOW?: 5.750"
wrong 1.599 is prob right answer
14. YOU ARE REINSTALLING PISTONS WITH NEW RINGS. THE RING COM-
PRESSOR WILL NOT FIT TIGHT AROUND A PISTON SKIRT AND THE RINGS
BIND ON THE BLOCK SURFACE. WHAT SHOULD YOU DO?: CHECK THE RING
END GAP.
15. YOU HAVE CHECKED THE CRANKSHAFT AND FOUND THYE FOLLOWING
MEASUREMENTS BELOW. THE ROD JOURNAL SURFACES ARE SMOOTH
AND NO ROD JOURNAL TAPER IS PRESENT. WHAT SHOULD YOU DO?
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