Shouldn't have to reset the pump timing unless it was adjusted to account for the stretch at some point...even then it would probably be close enough. My advice would be to replace the chain and time the pump if you know how. Otherwise just replace the chain and tensioner, I've seen a few 240D chains break and it is not good.

The chain is relatively easy to replace by (this is over simplifying but...) cutting the old chain, attaching the new chain to the old one, turning the engine by hand until the new chain is in place, separate the old chain and crimp the new one together.

Good luck!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer