Engine Performance
Work Example 14

WorkKey Level: 4
NATEF Automotive Tasks: VIII.A.9

The following are compression test results from an engine.  Specs state that the results should  be within 10% of the highest reading.  Are the results acceptable?  Show why.

120 psi

115 psi

119 psi

109 psi

117 psi

115 psi

                            

Solution:

10% of Highest Reading = (.10)(120)  = 12 psi
120 psi – 12 psi = 108 psi
Readings need to be greater than or equal to 108 or r > 108
Yes, all of the readings are acceptable and fall within the 10% range.