The engine

A.: What type of injection valve is used on modern engines?

В.: Modern engines use mechanical fuel injection and the valve is simply a spring loaded check valve with a nozzle on inner end containing one or more fine holes. When the pressure from the pump overcomes the tension of the spring the valve lifts and oil at high pressure is forced through the nozzle as a mist.

A.: What are some of the troubles experienced with injection valves?

В.: Leaks, due to grit or scale, burning of valve or seat, stick­ing of stem in its guide, bending of stem, leaky packing, clog­ging of atomizer plates and plugging of holes in flame plates or nozzles.

A.: How is a leaky injection valve repaired?

В.: Small leaks can be stopped by grinding the valve on its seat with very fine ground glass, carborundum, or prepared grind­ing compound, finishing up with polishing paste. If seat and valve are badly scored, the valve should be refinished by grinding in the lathe with a tool post grinder and the seat should be reamed, fin­ished up by grinding.

A.: What precaution should be observed in cleaning injection valve stems?

В.: Cleaning should be done with kerosene, emery cloth should be used sparingly, or not at all, as it wears away the metal and increases the clearance between stem and guide. If this clearance becomes too great it offers an easy place for gummy oil and car­bon to accumulate and the tendency of the stem to stick in the guide is increased.

A.: Why does the exhaust valve require more attention than the inlet valve?

В.: Because it is exposed to the action of the very hot gases that flow through it during the exhaust period. These gases may carry hard carbon, grit or scale which tend to cut the valve and seat and the heat tends to warp and burn the valve. The inlet valve passes no hot gas and is cooled by the inflowing clean air during each suction stroke.

A.: What is the best procedure for keeping valves in good con­dition?

В.: Do not wait for trouble to develop before examining valves. Establish a regular routine for removing valves for examina­tion and overhaul. This routine procedure is facilitated, if a com­plete set of spare valves is available so that the spares can be in­stalled while in port and the used valves overhauled at leisure. The length of time between examinations of valves can be es­tablished to suit the nature of the service the ship is engaged in.

Exercise 6. Speak on the following.

1) Derangements likely to occur in connection with starting dif­ficulties.

2) Derangements likely to occur in connection with water in fuel oil.

3) Derangements likely to occur in connection with improperly refined oil.

4) Derangements likely to occur in connection with loss of power or slowing down the engine.

5) Derangements likely to occur in connection with cracked cylinders and cylinder heads.

6) Derangements likely to occur in connection with cracked crank shafts.

7) Derangements likely to occur in connection with vibration.

5. Lesson 5. Engine shipyard repairs

Notes:

1) . . .without recourse to out­side help.	... не прибегая к посторонней помощи.
2) there are conditions, how­ever, under which this becomes impossible.	Однако, существуют условия, при которых это становится невозможным.
3) ... and many repairs re­quiring the engines to be disabled cannot be done. . ..	... и многие ремонтные рабо­ты, требующие вывода из строя двигателей, не могут быть выполнены . . .
4) in this case repairs are re­stricted practically to such items as may be carried out at sea.	В этом случае ремонтные ра­боты практически ограничи­ваются теми работами, кото­рые можно выполнить в море.
5) this flexibility seldom re­sults in any injury to the bed itself . . .	Эта гибкость редко приводит к каким-либо повреждениям самого фундамента
6) frames are subject to the same sort of deflection as the bed ...	Рама подвержена такого же рода прогибу, как и фунда­мент ....
7) ... or what may more pre­cisely be termed	. . . или, что, точнее говоря, можно назвать ....

The conscientious engineer who is responsible for the operat­ing efficiency of his ship takes pride in maintaining the machin­ery in good condition, without recourse to outside help. There are conditions, however, under which this becomes impossible. The operating schedule may be such that the engines must be available for operation most of the time and many repairs requir­ing the engines to be disabled cannot be done within the short time available for such work. In this case repairs are restricted practically to such items as may be carried out at sea. As the size of marine Diesel engines increases the individual parts become more massive and even routine examinations become too great a task for a small number of engineers and the limited equipment on shipboard. As a result, a large proportion of motorship repairs is done in shipyards. Such repairs may, in general, be grouped into three classes as follows: (1) maintenance repairs, or those resulting from ordinary wear and tear in service; (2) repairs re­quired as a result of faulty design, or changes due to improve­ments in design; and (3) repairs required as a result of accident, stress of weather, or other unusual conditions.