It might be worth while to see if you already have an Offset Woodruff Key installed.

Also at 300K you might need an new Timing Chain Tensioner Rail. I think the Crank Damper needs to be pulled to get at the lower Pin.

I have also seen pictures where the Timing Chain Tensioner spring has the sides of the Coils worn. You would need to remove the whole Timing Chain Tensioner assembly to change the Tensioner Rail.

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84 300D, 82 Volvo 244Gl Diesel