Answer A is wrong. If the gauge reads steady (17-22 in Hg) this indicates a normal running engine.

Answer B is wrong. If the gauge reads low (15-20 in Hg) this indicates late valve or ignition timing, leaking manifold gasket, low compression, leaking carburetor, or stuck throttle valve.

Answer C is correct. If the gauge readings fluctuate between (15 and 20 in Hg) this indicates a stuck valve or engine miss.

Answer D is wrong. If the gauge reading drops slowly at an idle this indicates a clogged or blocked exhaust.

Answer A is wrong. Weak spring tension is not a likely cause. Excessive spring pressure may cause the valves neck to stretch.

Answer B is wrong. The valve spring installed installed height is the distance from the pocket or cup where the spring sits to the outer edge of the retainer with the valve closed. It's a measurement not a possible cause.

Answer C is correct. A worn valve face or valve seat is most likely the cause. Check the valve stem installed height whenever any of the valves have been replaced.

Answer D is wrong. Loose head bolts would not be the most-likely answer.

Answer A. is wrong. An open oil pressure valve will cause low oil pressure.

Answer B is correct. A stuck closed oil pressure relief valve could cause high oil pressure and a ballooned oil filter.

Answer C is wrong. A stuck open bypass oil valve would not result in a ballooned filter.

Answer D is wrong. This is a most likely question. Contaminated oil would not likely result in this condition. It may cause an oil bypass valve to open.

Answer A is wrong. Do to the nature of their design torque to yield bolts or stretch bolts should not always be reused.

Answer B is wrong. Neither technician is correct. Cleaning a bolt that is stretched will not restore it to its original length.

Answer C is wrong. Neither technician is correct. This answer could be true if the TTY bolt passes all of the manufacturers required specifications. Just be careful with these bolts that's all.

Answer D is correct. Neither technician is correct.

Answer A is wrong. Answer C ic correct.

Answer B is wrong. Answer C is correct.

Answer C is correct. A dial gauge is used to measure end-play clearance.

Answer D is wrong. Answer C is correct.