What jumper settings have you set on the drive? Are the connectors seated properly when you've connected the drive up?
Have you tried powering the drives up in a PC to ensure they powerup and can be seen properly by the BIOS?
When you switch on, can you get into the installer's menu and houskeep?
I have a 4R120L0 in a v1 Sky+ and it works very well, runs very cool, & is silent, no fan needed. I'm a bit surprised at you having problems, it may well be something quite simple I hope.
Furthermore I believe your 4R160L0 is the drive used in the Sky 160, and I have seen a post from another user here using your drive, so I think this info should also be reassuring.