Compression test?
 

Is there any way to check compression on a engine that isn't in a vehicle? What would I need to do?

you can't really test the compression without it in the motor. What you can do is look through the exhaust port of the alluminum housing and look at each apex seal as it passes past the port. With the spark plugs installed, turn the motor and listen for a pop as you turn to each face of the rotor.

If it has a transmission and a starter out of the car, you could mate the the engine to them, and use a battery to spin the enigne. Check it with a compression gauge like that.

Yeah. Battery hooked to negative terminal on the starter, should run it about 250rpms. That's a good base to check it on. Make sure you take out the valve in the compression tester, or it will not bounce at all.

Do I have to have the transmission connected? Also if I test this way, what numbers should I look for?

Yes, that's what the starter hooks into. Unless you're Superman and can hold a starter onto a flywheel. :)

Yeah, now I feel stupid. Okay, so what should I look for with compression if tested this way?