ASE A1 Engine Repair Practice Test
46. After performing a cylinder pressure test on a four cylinder engine, the #1 cylinder is 30 psi below specifications. All the other cylinders have passed. The pressure in the #1 cylinder increased after injecting engine oil. Technician A says excessive carbon buildup on the piston head has caused these test results. Technician B says these results indicate a faulty intake or exhaust valve. Who is correct?
- A. Technician A
- B. Technician B
- C. Both A and B
- D. Neither A or B
Answer A is wrong. Neither technician is correct.
Answer B is wrong. If there is no increase in compression, the head gasket or one of the cylinder's valves are at fault.
Answer C is wrong. If the piston rings are worn, the pressure readings will increase after introducing oil into the cylinder and rotating the crankshaft. There will be little or no change if a valve is at fault.
Answer D is correct. Neither technician is correct. When injecting oil increases the cylinder's pressure, the piston rings are faulty. Compression is blowing past this weak seal.
47. One valve tip on a cylinder head is much higher than the others. The MOST likely cause of this is:
- A. Weak spring tension.
- B. Valve spring installed height.
- C. The valve seat.
- D. Loose head bolts.
Answer A is wrong. Weak spring tension is not a likely cause. It results in valve float and a misfire at high engine speeds. Excessive spring pressure may cause the valve's neck to stretch.
Answer B is wrong. The valve spring installed height is the distance from the pocket or cup where the spring sits to the underside of the retainer/rotator with the valve closed.
Answer C is correct. A worn valve face or valve seat is the most likely cause. Check the valve stem installed height whenever any of the valves have been replaced.
Answer D is wrong. Loose head bolts result in a loss of compression, overheating and white colored exhaust.
48. Two technicians are discussing a ballooned oil filter. WhIch of these is causing this condition:
- A. Contaminated oil.
- B. Stuck closed oil pressure relief valve.
- C. Stuck closed oil filter bypass valve.
- D. All of the above.
Answer A is wrong. Contaminated oil will clog the filter, if the oil filter bypass valve is stuck closed. This will result in a swollen and ballooned filter.
Answer B is wrong. A stuck closed oil pressure relief valve would cause high oil pressure and a ballooned oil filter.
Answer C is wrong. A clogged filter and a stuck closed oil bypass valve would result in a ballooned filter.
Answer D is correct. Each of these conditions would result in a ballooned oil filter.
49. The best tool for checking crankshaft end play is a:
- A. Bore gauge.
- B. Digital micrometer.
- C. Dial indicator.
- D. None of the above.
50. An engine has excessive crankshaft endplay. Which of the following is MOST likely causing this condition?
- A. Camshaft bearings
- B. Thrust bearings
- C. Crankshaft main bearings
- D. Rod bearings
Answer A is wrong. Thrust bearings locate and keep the crankshaft from moving foreword and backward in the engine block.
Answer B is correct. The thickness of the thrust bearing indicates crankshaft endplay.
Answer C is wrong. Answer B is correct.
Answer D is wrong. Answer B is correct.