ENGINE DIAGNOSTIC TOOLS Section 4 CALIBRATING THE PRESSURE TEST KIT (SE-2239) USING THE DWYER SLACK TUBE® MANOMETER (Continued) 4. Read manometer as follows: (Continued) Use  the  conversion  factor  one  inch  of  mercury equals    0.4912    psi    to    determine    the    actual pressure in pounds per square inch. 15.15 x 0.4912 = 7.44 psi Read  the  gauge  pressure  again  to  determine  if any air leakage has reduced the gauge pressure from six psi.  If the gauge pressure still reads  6 psi,  we  have  determined  that  the  gauge  reads 1.44 psi lower than the actual pressure. Record     the     gauge     pressure,     corresponding mercury   manometer   reading,   and   convert   the manometer  reading  to  psi  for  each  gauge  psi from 6 to 22 psi.  Repeat the calibration test from 6 psi to 22 psi to double check for air leaks and accuracy of gauge and manometer readings. Gauge PSI Inches Actual Reading of Mercury Conversion PSI 6 7.65+  7.50= 15.15x0.4912=  7.44 15.15 7 8.65+  8.45= 17.10x0.4912=  8.39 17.10 8 9.70 +  9.45 = 19.15 x 0.4912 =  9.40 19.15 9 10.80+ 10.40 = 21.20 x 0.4912 =  10.41 21.20 From the above information, make up a correction chart for the gauge and place it on the gauge panel. Gauge PSI Reading Actual PSI 6 7.4 7 8.4 8 9.4 9 10.4 Guideline   intake   manifold   pressures   for   each   engine horse power rating are printed on the "PERFORMANCE DATA GUIDELINE" pages at the rear of each  Engine  Section.    Each  pressure  has  a  +1.5  psi range.    For  example,  the  DTI-466B  rated  at  210  HP  at 2600  RPM  pressure  of  125  +  10  kPa  (18  +  1.5  psi)  at 2600 RPM.  An engine operating with 117-138 kPa (17- 20 psi) pressure will produce the rated horsepower at the flywheel.      Using   this   calibration   procedure   to   test   the accuracy of the 0-30 psi gauge before measuring engine pressure will assist you in evaluating engine performance.        Using    an    accurately    calibrated    boost gauge    along    with    the    diagnostic    procedures    in    this manual,   will   allow   you   to   determine   if   the   engine   is producing  rated  horsepower  and  eliminate  unnecessary engine component changes. ROBERT BOSCH SMOKE SAMPLING KIT (SE-2580) DESCRIPTION The  smoke  sampling  kit  (Figure  14)  is  used  for  reading smoke  density  at  the  exhaust  stack  at  rated  load  and speed only to determine acceptability of smoke emission. Figure 14.  Smoke Sampling Kit OPERATION In the smokemeter, a sampling pump draws off a certain amount  of  exhaust  gas   from   the   exhaust   pipe   of   the respective engine and then sucks it through a filter paper disk.  The filter paper disk, CGES-240-4 Printed in United States of America Page 20