| 1. Oil Contamination |
Chemical
Contamination
causes heavy wear of bearing/ shaft and excessive temperature .
The visual indications are very much the same as for Marginal
Lubrications. The most common cause is dilution of oil by fuel,
reducing the lubrication properties of oil.
Total Lack of Lubrication
for similar causes, will show similar damage, but more extreme.
Damage happens very rapidly! |
|
Fine Particle Contamination may not be noticed in
oil visually, but causes polishing of the bearing surface and tell tale
rounding of the outer edges. Often the compressor end bearing may be
worn to a taper on the outside diameter.
|
|
Large Particle Contamination
Oil borne large particles, may cause impact
damage and deep scoring as shown left. The bearing bore may also be
scored, usually to a lesser extent. The shaft and center housing are
usually damaged slightly less, being harder materials. The light scoring
shown below was caused by large oil borne contaminations. |
2. Lack of Lubricants |
Marginal Lubrication
when the oil supply to the turbo is reduced, (for instance when
gasket materials partially block an oil way or inlet flange).
Characterised by extreme discolouring of shaft journals (as shown).
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