Is there a woodruff key used on crnk pully 1992 volvo 740?

[Ric Lang]

I removed crank pully. I see a keyway on pully, but there is no key. I cannot believe the crank pully bolt will hold the pully in place without a key. How do you ensure the timing marks on pully won't slide away? If there IS a key, where do I get one? Volvo dealers say they have NO such key listed in their parts manuals.