Arizona republican., 1918-09-01
By William H. Stewart Jr., In the New
 York Tribune

ICfN tflpuiS
 An interesting case of loss of engine power came to my attention recently. A friend had complained frequently that his engine was troubled With carbon. He had the cylinders cleaned and then employed the usual methods to reduce carbon deposits. Still the carbon accumulated faster than he could keep it down, accompanied by symptoms such as weak power. engine missing explosions sluggishness when throttle was opened, and carbon knock pulling hills.
 The symptoms of carbon were all present, including the knock, particu larly on a hill. and a trail of bluish- white smoke following the car and in- dicating that the engine was piling up more carbon as fast as it could. He assured me that the carbon had just been cleaned out and the valves ground When asked about the com pression he admitted that he did not know how to test It.
 This is enc of the disadvantages of the Self-Starter-a person doesn't have to crank the engine by hand. Former ly one always knew whether the engine Lad good compression or not because he tested it every time he started it. and any loss of compression became immediately evident. So my friend uncovered the starting handle from pile of rubbish under the rear scat and we cranked the engine.
 Compression was weak in all the cylinders. The valves hac just been ground. so we ran the engine and in lected oil around the valve caps, spark plugs. and compression relief valves. Since no bubbles came through the oil We knew they were tight Inspection | of the clearance between valve filters | and valve stems showed a space suffi- | ciently large to admit piece of news | paper. proving that the valves were not | held off their seats.
 The only place remaining where compression could escape was around | the piStons. caused by second or oval cylinders or trouble with the rings such as their being badly worn, broken, scored, slots in line or gummed by carbon and stuck in their grooves, so that they could not spring out. On starting the engine again and holding the hand over the br2ather tube the | mystery was solved.
 Such a rush If gas came out that il was evident nest of the power was leaking into the crank case md the oil
 was drawn up to the top of the piston at every suction stroke. This trouble
 was aggravated by some of the unevap-
 orated gasoline leaking down into the
 crank case, thinning the oil. reducing
 it's lubrlcating qualities with conse-
 quent loss of power through friction
 This thin oil was sucked up all tho
 more readily on the suction stroke | .S-e+ +f,9-v hn tr-nt f,In
 Our first attempt at remedy was tC
 pour half tea acupful of kerosene into each cylinder and to crank the engine
 by means of the self starter, in ordel
 to free the rings, in case they wcr,
 stuck in tte grooves. After seyera
 minutes of this we again tried th, compression by hand. to find no i'm , pavement. I left him after he hat reasons for this First. concerning tn 7 volume of gas used: in order to mak , use of the power generated by tn burned gas the piston must travel ou of the cylinder. When it is all tn
 way in the cylinder the space abov the piston which contains the charge O : gas is only about one fifth of tha l when the piston has travelled all tn p way down. Therefore, by drawing il [ a full cylinder of gas and then com f pressing 1t into small space at tn
 top, about five times the volume O
 gas is usod, giving five times tn
 power.
 n Second. when the gas is compresse s it will ignite much more readily an l burn much more evenly. In fact. it
 possible to have so much corpressio 0 that the gas will ignite from that caus Q alone. and frequently there is re-igni : tion because of too high compression e Loss of compression, therefore, meor Q loss of power and waste, because fu Q cylinder of gas is taken in and onl d part of it used. and the explosions al n weak and irregular.
 2 There is something of the action
 q coil spring in compressing the ga $ The force of the compression alor q would send the piston back to poir
 where there was no compression. Ru h just at the point of highest compres n sion. a spark is introduced, which. |