The total length of the engine is basically determined by the bore, the bore pitch, and the cam gear train layout.
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Comparison of gear train layout in Audi R10 V12 TDI and R15 V10 TDI engines
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The total length of the engine is basically determined by the bore, the bore pitch, and the cam gear train layout.
Comparison of gear train layout in Audi R10 V12 TDI and R15 V10 TDI engines