Logic board swap problems with severe overheating

Hello, I have recently had to buy a new logic board for my 2011 MBP A1278 i7 . I decided to try a risky upgrade by buying a 2012 A1278 i7 logic board and putting it into the 2011 body. I researched it and I knew the board would fit . I am using all existing components from the 2011 i.e heatsinks, fan. Now my problem is the machine over heats to the point of shutting down and giving me three beeps . This happens very very fast . I had to install a fan controller to ramp the fans to max speed so I can use the laptop for simple tasks as watching YouTube. The internal fans seem to not pick up speed on their own and the CPU temps just go through the roof .

My question is , is there any different between the models components like the heatsink or fan ? Would buying a 2012 heatsink and fan fix the problem? Or is there anything else I can do to fix the situation? After rebuilding the computer (I had to replace the LCD also) the webcam does not work and I read somewhere that there is a sensor on it or something ? Any help would be amazing as I am very close to setting the macbook on fire.

Stephen