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0050 - Recognizing dust damage to the pistons and cylinder liners Engines OM 364, 366, 366 A/LA, EURO I

Typ ra · téma 03.00 · verze 9503 · 1995-01-15

Platí pro:

Není k dispozici v jazyce „cs“; zobrazeno v jazyce Angličtina.

Zařazení

Funkční skupina 1 Motor › 03 Pohonná jednotka › 03.00 Všeobecné — Řada 364 (modely 918)

Platí také pro motory/převodovky: 356 901, 356 902, 356 903, 356 904, 356 905, 356 906, 356 907, 356 908, 356 909, 356 910, 356 911, 356 941, 356 943, 356 944, 356 945, 356 946, 356 947, 356 948, 356 949, 356 951, 356 952, 356 953, 356 979, 356 983, 356 986, 356 987, 356 989, 356 990, 356 991, 356 992, 356 993, 356 994, 356 995, 356 996, 356 999, 366 941, 366 942, 366 943, 366 999

03-0050 Recognizing dust damage to pistons and cylinder liners

Note

If oil consumption is high or if the engine fails, it is often not clear whether the damage results from dust or from normal wear and tear.

Possibilities of recognizing dust damage

Severe deposits of dust in the elbows of the intake passages at the clean air end (between air filter and engine) are a clear indication of dust damage. A very fine coating is permissible on engines with an oil bath air filter.

The stem contact pattern of a piston and the honing pattern of a cylinder also provide indications regarding damage resulting from heavy concentrations of dust.

0050 - Recognizing dust damage to the pistons and cylinder liners Engines OM 364, 366, 366 A/LA, EURO I

Piston without dust damage

The stem contact pattern of the piston is large in appearance and the machining marks are still clearly recognizable withing this area.

Note

The machining marks around the circumference are intentional recesses which are filled with oil and contribute to improve the lubrication.

0050 - Recognizing dust damage to the pistons and cylinder liners Engines OM 364, 366, 366 A/LA, EURO I

Piston with dust damage

The contact pattern at the stem is matt in appearance and the machining marks are completely worn off within the contact surface. In an advanced state, slight seizure marks already exist on the stem and the piston rings are sharp-edged.

0050 - Recognizing dust damage to the pistons and cylinder liners Engines OM 364, 366, 366 A/LA, EURO I

Cylinder liners without dust damage

The honing is recognizable over the entire contact surface - more or less clearly depending on the type of engine. The honing may be partially eroded at the reversal point of the first piston ring.

0050 - Recognizing dust damage to the pistons and cylinder liners Engines OM 364, 366, 366 A/LA, EURO I

Cylinder liners with dust damage

The machining marks from honing are visible only very weakly or not at all.

In an advanced state, a wear shoulder can be felt at the reversal point of the first piston ring. Poor sealing of the intake passages at the unfiltered and clean air ends (upstream and downstream of the air filter), grooves or chafing points at the intake hose, increased dust deposits, entraining of dirty oil from the oil bath air filter (if excessive quantity of oil used), installation of non-approved start pilot versions and such like can cause dust damage.

When performing servicing, it is therefore necessary to carefully check all the intake pipes and connections so as also to determine any concealed leak points or cracks.

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