13.  Q. What effect does too much pressure produce?

A. Wastes grease and increases the friction until the surplus amount is worked out so the bearing runs free on its journal.

14.  Q. Is it necessary to use oil with grease on crank pins?

A. No.

15.  Q. When an engine is equipped with Elvin driving box lubricator, how can you tell whether a sufficient amount of lubricant is in the grease receptacle?

A. The indicator wire fastened to the bottom of the grease cellar indicates the amount of grease left in the cellar.

16.  Q. Why should engine oil not be used on valves and cylinders?

A. Engine oil loses its lubricating qualities before it gets up to the temperature of the valves and cylinders when they are working steam.

17.  Q. At what temperature does engine oil lose its lubricating qualities?  At what temperature for valve oil?

A. Engine oil begins to separate and give off gas at 345 degrees F. The temperature of steam at 120 pounds is 350 degrees F., while valve oil has a flash test of 520 degrees F. The temperature of steam at 235 pounds is 431 degrees F., much lower than the flash test of valve oil.

18.  Q. How and by what means are valves, cylinders and the steam end of air pumps lubricated?

A. By a sight-feed hydrostatic lubricator.

19.  Q. What is the principle on which a lubricator operates.  How does the oil get from the cup to the steam chest?

A. The lubricator is located in the cab so there is a gradual descent in the oil pipe from the lubricator to the steam chest.  Above the oil reservoir is a condenser that is kept filled with water condensed from steam fed from the boiler.  The pressure of this water comes on the oil in the oil tank below it, forcing oil through the sight-feed valves; it then passes up by the sight-feed glasses to the oil pipe and steam chest.  The use of the glasses is to make the drop of oil visible as it leaves the sight-feed nipple so the amount of oil fed can be regulated.  Steam from the boiler fed to the lubricator at boiler pressure through the equalizing tubes balances the pressure which comes from the steam chest when the engine is working steam.

20.  Q. How should the lubricator be filled?

A. First close all valves connected with the lubricator, open drain plug and remove filling plug, allowing water to escape until oil appears with it.  Drain plug should then be closed.  Fill the oil tank in the usual way, being careful not to overflow it; then replace filling plug.  If the supply of oil is insufficient to fill the lubricator, water can be used to finish it, as the lubricator will begin feeding sooner when filled full.

21.  Q. After filling lubricator, what should be done?

A. Open the steam throttle to the lubricator wide, then carefully open the water valve, but do not open the feeds until sure the chamber in the glass is filled with water.