Rubber insulation failure sparked Hamilton's exit from Australian Grand Prix

ERJ staff report (BC)

London – A hairline split in the side of a rubber tube surrounding the Mercedes spark plug was the cause of Lewis Hamilton's retirement from the Formula 1 season opener in Australia, Jonathan Nobel reported for Autosport.

Hamilton was forced to withdraw from the race in Melbourne after his engine dropped a cylinder at the start of the race.

The team initially suspected a wiring issue was to blame, but it has now revealed that the real cause was a small split in the side of the blue rubber tube.

The tube is supposed to insulate the current flow into the plug, but the tiny split led to the spark cutting a hole clean through its side instead.

Mercedes believes that this hole developed over the Melbourne weekend (15-16 March) and led to the spark shorting onto the cylinder head on the formation lap – causing the engine problem.

Mercedes' F1 engine chief Andy Cowell told Autosport: "It is really frustrating.

"The hole was blown through the side of the rubber tube – and it shorted through the rubber boot across to the cylinder head.

"The hole was eroded by the spark jumping across. It meant that at low demand it was still working – so idle and the parade lap was fine – but as soon as it went to full load the spark would rather jump the rather large gap to the cylinder head than the [ignition] gap."

It is the first time that Mercedes had encountered such a problem throughout all its bench testing, track test and race running.

Following inspection of all the identical rubber tubes used by its teams in Melbourne, Hamilton's was the only one that had failed – although similar faults were discovered in tubes in Mercedes' Brixworth [Northants, UK] factory stores.

To prevent a repeat, Mercedes has refined the manufacturing process for the tubes to eliminate the seams where the fault developed – so they are now injection moulded – and it has thickened up the area where the hole developed.

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