OECP Automotive Engine Exit Exam Reviewer — 100- Correct Questions & Answers (Bearings, Valves, Compression, Timing).pdf

A complete exam reviewer for automotive and mechanical engine diagnostics, featuring verified questions and correct answers across bearings, compression testing, valve adjustments, lubrication, and crankshaft measurements. This resource is designed to help mechanics, technicians, and engineering students prepare for certification or exit exams with confidence. Key topics covered include: - Bearings & Crankshaft - Plastigage results: Insert “A” has more clearance. - Crankshaft endplay checked after torquing main bearing caps, using a dial indicator. - Standard bearings installed when journals are smooth and within spec. - Compression & Head Gasket - V‑8 compression test: 50 PSI in two cylinders indicates a blown head gasket. - Compression test procedure: throttle and choke must be fully open. - Bubbles in coolant with radiator cap off = leaking head gasket. - Valves & Lifters - Excessively worn valve guides: all listed symptoms apply. - Intake valve deposits: both B and C. - Valve spring check: installed height. - Valve tappet clearance adjusted at TDC on compression stroke. - Hydraulic lifters noisy at highway speeds → check crankcase oil level first. - Valve timing controlled by belt, chain, or gear drive. - Running hydraulic lifter clearance: .006"–.008". - Purpose of clearance: compensate for temperature change and wear. - Exhaust valve margin after grinding: 3/16. - Mechanic measuring valve guide wear and concentricity. - Lubrication & Oil Pressure - Warm engine with low oil pressure → leaky main bearing seals. - Fuel & Carburetor - No fuel squirt when throttle opened quickly → all listed causes possible. - Measurements & Tools - Shaft tolerance 2.125 ± .015 → range 2.062–2.250. - Bore taper found by subtracting measurement D from C (correct method). - Micrometer reading correction: ~1.599" (not 5.750"). - Cooling & Water Pump - Fan blade tip play (⅛–¼ inch) = worn water pump bearing. - Bolts & Fasteners - SAE Grade 5 bolt identified as option C. This reviewer provides exam‑style Q&A with concise rationales, making it ideal for mechanics, automotive students, and engineering trainees preparing for OECP or exit exams