It can fit, as the M11 is the same size as L10. Volvo did claim that they could not
do it, when the L10 engine was withdrawn from offer when the Olympian transited
to Euro 2 emission standard. However, Lothian Bus of Edinburgh attempted, and
successfully, fitted a M11 unit into one of their Olympians.
No, the only two things that the B10TL shares with the Olympian, Leyland or Volvo, are 1. the name, 2. the engine compartment. The chassis forward of the rear axle, in fact, comes from the B10L/B7L developed in the 90s.
The self-steer mid-axis of the Olympian is only there to reduce tyre wear. It does not improve its maneuverability at all, contrary to what many people believed. Removing that feature on the B10TL (and of course the follow-up B9TL) provides better maneuverability, and reduce the mechanical component which, as a result, reduce maintenance headaches.
The most important feature of the Olympian is actually the engine compartment, which is designed to reduce vibration from the engine by suspending it, rather than lying it on the chassis frame. This design continue to live on Volvo's B7TL and B9TL, as well as Dennis 2-axle Trident.
