[v8volvo]

The point is to reduce friction by using the oil (only on the threads and under the bolt head -- don't let any get on the surface between the cam and the sprocket, for obvious reasons...). If you reduce friction, then you can get the same holding power with way less torque on the fastener. The idea of my advice is to use *less* torque than the engine manual advises. The torque spec for that bolt is 85 ft-lbs, but if you use the above method, 40 or 50 lbs will be just fine, and it will be MUCH easier to get it back apart in the future. It also means you can do the job without requiring the special tool that you would need in order to actually get 85 ft-lbs on that fastener -- it is an S-bend wrench with a 19mm box on one end and an attachment for a 1/2"-drive big torque wrench or breaker bar on the other. If you are using oil and getting the mating surface super clean and dry, you can just use a regular 19mm box wrench (or better yet, a ratcheting box wrench with a flexible head -- makes the job even easier) and use much less torque than the book calls for, and have faith that it will hold just fine and not slip. Then you won't be cursing yourself the next time you need to take it apart, either.