ITHOUT A DOUBT the best way to assess the
condition of an engine is to tear it down. But almost as good a tool for diagnosis
is spectrochemical analysis, or oil analysis. Since different parts of an engine are
made from different metals, the presence of these particles in the oil can be an
indicator of increased wear.
The chart below shows the raw data of oil samples from the Yachting Magazine
study. The top half represents the samples taken from the starboard engine using
petroleum; the bottom half reflects samples taken from the port engine which used
Each green-shaded row represents an oil change. Both engines were run on petroleum
for 100 hours just prior to the test to compare their wear patterns (Sample 1), which
are fairly similar.
Symbols: Fe (iron), Pb (lead, from leaded gas), Cu (copper), Cr (chromium), Al (aluminum), Ni (nickel),
Ag (silver), Sn (tin), Mo (molybdenum), Cd (cadmium), Sb (antimony), PC TS (% of