Early in the development of the L-1011, Rolls-Royce has significant problems with the RB211-22C engine resulting in several design changes that delayed the introduction of the L-1011.
This led to the bankruptcy of Rolls-Royce and the near bankruptcy of Lockheed.
Delta hedged their bets by ordering 5 DC-10-10 airplanes and stayed with the L-1011. Eastern tried to start wide body service by leasing 3 747-100's from Pan Am, but their reliability (or lack of) did not help Eastern at all.
Then further major reliability problems with the RB211-22C, including a fan disc burst in December, 1972 and Eastern losing the first wide body ever in the Everglades west of Miami at the end of December did nothing to help L-1011 sales.
The changes to the RB211-22C became so significant that the engine was redesignated the RB211-22B. I don't know why the "B" succeeded the "C", but it did.
Until the RB211-524 engine came out, the RB211 was not considered a very good engine.
had the same problem with the JT9D-3, but for other technical reasons, and the JT9D-7 series were much better engines.