One of the biggest problems on the diesel though is chain stretch which throws the timing off enough to kill the power output and fuel economy.
And that is reason enough to make the change. They sell off-set cam keys for this,
but the easy and best solution is a new chain. You can buy a repacement w.master link that , hooked to the old chain, threads
through the gears with ease. I use a bungee cord to keep tension on the chain and turn the crank by hand in the running direction.
Any that have done this will tell you it is not a big expensive job. It is also advisable to check the chain tensioner.