BMW B58TU Reference Manual page 14

B58TU￿Engine
2.￿Engine￿Mechanical
The￿main￿difference￿between￿the￿chain￿drive￿compared￿with￿the￿B58￿engine￿is￿the￿move￿from￿a￿two-
part￿timing￿chain￿drive￿to￿a￿single-part￿timing￿chain￿drive.￿Deflection￿via￿the￿intermediate￿shaft￿on￿the
top￿timing￿chain￿and￿the￿second￿timing￿chain￿is￿no￿longer￿needed.￿The￿chains￿used￿here￿are￿8 mm
sleeve-type￿chains.￿Because￿the￿intermediate￿gearing￿is￿no￿longer￿needed,￿the￿number￿of￿teeth￿on￿the
crankshaft￿(23 teeth)￿and￿the￿VANOS￿adjuster￿(46 teeth￿each)￿has￿also￿changed.
Chain￿track
Comparison￿between￿chain￿track￿of￿B58￿engine￿and￿B58TU￿engine
Index
A
B
1
2
3
4
5
The￿way￿the￿combined￿oil￿vacuum￿pump￿is￿driven￿via￿a￿separate￿drive￿chain￿from￿the￿crankshaft￿has
not￿changed￿compared￿with￿the￿Bx8￿engines.￿Only￿the￿change￿of￿the￿chain￿tracks￿has￿changed:
The￿drive￿chain￿of￿the￿oil￿vacuum￿pump￿is￿now￿in￿front￿of￿the￿timing￿chain.
Dropping￿the￿second￿timing￿chain￿offers￿the￿following￿benefits:
• Improved￿acoustics
• Lower￿space￿requirement
• Reduced￿weight
Explanation
Chain￿track,￿two-part￿timing￿chain￿drive￿B58￿engine
Chain￿track,￿single-part￿timing￿chain￿drive￿B58TU￿engine
6-cylinder￿engine
Upper￿timing￿chain
Timing￿chain
Lower￿timing￿chain
Drive￿chain,￿oil￿vacuum￿pump
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