ASE T1 Truck Gas Engine Prep practice questions and answers 2026. Tap an option to test yourself — you'll see the correct answer and a plain-English explanation for every question. Free, no login.
Q21A technician is checking valve seat width. The specification calls for 0.040-0.060 inch (1.0-1.5 mm). The actual measurement is 0.080 inch (2.0 mm). The MOST appropriate action would be to:
✓ Correct answer: D. Recut the valve seat to narrow it to specification
When valve seats are too wide, they should be recut to narrow them to specifications. Wide valve seats can cause poor valve seating, reduced heat transfer, and potentially lead to valve burning or poor engine performance.
Q22When installing rocker arms on a cylinder head with adjustable valves, the valves should be adjusted when the piston is at:
✓ Correct answer: C. Top dead center (TDC) on the compression stroke
Valve adjustment should be performed when the piston is at top dead center (TDC) on the compression stroke. This ensures both valves are closed and provides the proper reference point for setting valve lash according to manufacturer specifications.
Q23During valve spring installation, which of these measurements is MOST critical?
✓ Correct answer: B. Valve spring installed height
Valve spring installed height is the most critical measurement during installation because it directly affects spring pressure. Incorrect installed height can lead to improper valve operation, premature valve or seat wear, and potential engine damage.
Q24A technician is checking cylinder head flatness with a straightedge and feeler gauge. The maximum warpage found is 0.005 inch (0.13 mm). Which of these is the MOST appropriate action?
✓ Correct answer: A. Reuse the cylinder head without resurfacing
Since the warpage is within typical manufacturer specifications (usually 0.008 inch or less is acceptable), no resurfacing is required. The cylinder head can be reused as is, saving time and maintaining the original head thickness.
Q25Technician A says that camshaft bearings should be installed with the oil holes aligned with the cylinder head oil galleries. Technician B says that camshaft endplay should be measured after bearing installation. Who is right?
✓ Correct answer: D. Both A and B
Both technicians are correct. Camshaft bearings must have their oil holes aligned with the cylinder head oil galleries to ensure proper lubrication, and camshaft endplay must be measured after installation to ensure it meets specifications and allows proper operation.
Q26When torquing cylinder head bolts, which of these methods is MOST commonly specified by manufacturers?
✓ Correct answer: C. Torquing in a specific sequence and in multiple steps
The most commonly specified method for torquing cylinder head bolts is a multi-step sequence with a specific pattern. This ensures even clamping force across the head gasket and prevents distortion of the cylinder head or block during assembly.
Q27A technician is inspecting an engine block for cracks. Technician A says that fluorescent dye penetrant testing is an effective method for finding cracks. Technician B says that magnetic particle testing can only be used on aluminum engine blocks. Who is right?
✓ Correct answer: B. A only
Fluorescent dye penetrant testing is effective for finding cracks in engine blocks. Magnetic particle testing can only be used on ferrous (iron-based) materials, not aluminum blocks.
Q28A technician measures a cylinder bore and finds it to be 0.003 in. (0.076 mm) out of round. What is the most likely cause?
✓ Correct answer: A. Normal wear from piston movement
Cylinder bores typically wear in an oval pattern due to the side thrust forces of the piston, resulting in an out-of-round condition. This is normal wear caused by the piston's movement during the power stroke.
Q29When measuring main bearing clearance with Plastigage, what should be done before taking the measurement?
✓ Correct answer: D. Clean the crankshaft journal and bearing surface
Before using Plastigage to measure main bearing clearance, the crankshaft journal and bearing surface must be thoroughly cleaned. Oil or contaminants will affect the accuracy of the Plastigage reading.
Q30During an engine block inspection, a technician finds a crankshaft main bearing journal that is 0.005 in. (0.127 mm) smaller than the other journals. What should the technician do?
✓ Correct answer: C. Replace or recondition the crankshaft
A main bearing journal that is significantly smaller (0.005 in.) than others indicates uneven wear or improper previous machining. The crankshaft should be replaced or reconditioned by grinding all journals to the next standard undersize.
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