I see this all the time, how is this done?

 

You can get a tool to bolt to the balancer that you can turn with a wrench or breaker bar, or you can get a tool that turns it by the flexplate/flywheel teeth. Some people turn it by the balancer bolt, which how a lot of balancer bolts get broken off in the crank snout.

Any way you do it, it's a lot easier if you take the plugs out first.

 

I guess this is to relieve pressure right?

There was no real reason for this question, just wanted to know how it was done.

 

Right, otherwise you're fighting compression while you turn it.

You can also bump the engine over with the starter, either with the ignition switch or with a switch clipped onto the starter.

 

I wouldn't recommend turning by the balancer bolt even though its easiest way. I do it but also take all my plugs out and usually have my plenum off.

Still not good...

 

[QUOTE=CamarosRUS]I wouldn't recommend turning by the balancer bolt even though its easiest way. I do it but also take all my plugs out and usually have my plenum off.
QUOTE]
There is a tool sold at some automotive stores that you install on pulley attached to your balancer. You just remove the 3 bolt on the pulley (make sure belt is off) install tool and install the 3 bolts back on the pulley. The one I have allows me to use a 1/2 drive or a 1" socket to turn the engine. As CamarosRUS has stated, it would unwise to turn the engine using the actual balancer bolt.