Endurance test BMW K 1200 RS (Dekra to engine damage)

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Endurance test BMW K 1200 RS (Dekra to engine damage)

Last act

A neutral appraiser inspected the burst K 1200 RS engine

At 18,100 kilometers the endurance test BMW had K 1200 RS suffered major engine damage (see MOTORRAD 21/1997). The BMW diagnosis: The death was due to a lack of oil for which the editorial staff was responsible, so there were no guarantee claims. However, using the logbook, MOTORRAD can prove that the oil level was always correct. Reason enough to entrust the matter to an independent expert. A DEKRA specialist determined that there were several possible causes (see below), but that an absolutely reliable diagnosis is no longer possible due to the dismantled and cleaned parts. A MOTORRAD employee or the DEKRA expert should have been present for the final clarification when the engine was dismantled by BMW.

DEKRA: Expert opinion in the original text – last act

The main damage occurred in the area of ​​the first cylinder. Here all four valves were damaged by the piston, the piston itself was completely destroyed, the connecting rod torn off and twisted, the bearing cover broken, the crankshaft hammered and the engine block destroyed. The piston skirt of the second cylinder showed severe dirt scoring. At the connecting rod bearing of the third cylinder, friction has occurred between the bearing shell and the crankshaft. Here the running layer of the connecting rod bearing was significantly affected. The engine was destroyed while driving on the motorway. The engine was dismantled and examined at BMW in Munich. According to information from MOTORRAD, the BMW company diagnosed an interruption in the supply of lubricant due to a lack of engine oil as the cause of the damage. From a technical point of view, this diagnosis can be considered as the cause of damage, but it contradicts the engine oil level check carried out continuously by the vehicle owner, as explained above. From a technical point of view, it would be entirely possible that the short-term metallic friction between the bearing shell and the crankshaft journal could also have occurred during the 10,000-kilometer inspection and then, in the course of time, with an existing lubricant supply, would have expanded to the damage found. Black plastic compound has melted between one of the two connecting rod fastening screws and the connecting rod. The melting of the plastic compound occurred due to the large amount of heat generated when the engine block and the fairing were broken through. It is clear evidence that one of the two connecting rod fastening screws was loosened at the time of the damage. This may have been a consequence of the constant hammering due to the increased bearing play. However, it is also conceivable that the screw has loosened, increasing the bearing play and thus no more lubricious oil film could be built up, which then caused damage. Two fragments of the piston show clear traces of friction on the inside of the piston pin seat see. The same applies to the connecting rod cheek in the area of ​​the bearing boron. This is an indication that the connecting rod was not properly angled. This is also a possible cause of the damage that has occurred. Summary The cause of the damage stated by BMW is one of several conceivable possibilities for the damage pattern found. A definitive statement as to which of the possible causes was ultimately the cause of the damage can no longer be made due to the found, completely dismantled and cleaned condition of the parts.

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