Things I've learned this week...

   Let's see, I've learned how to adjust intake/exhaust valves; the proper way to hold a micrometer; what keeps bearing halves in place; the meaning of crush; and the difference between a turbocharger and a supercharger.
  
   The bearing crush (when you torque the case halves together) is what keeps the bearings in place when running.

   Crush- the outward force created by the portion of the bearing that extends above the housing bore when the bearing halves are set into place.

   Turbochargers VS Superchargers-

• Turbochargers are powered by spent exhaust gases, which are used to spin a paddle-wheel-like part called an impeller. The impeller is connected on a shaft to the turbine, which has vanes on it to compress the incoming air, thereby creating boost, or pressurized induction.A wastegate is built into the system to prevent over-pressurization by venting the exhaust gases away from the impeller. Usually, the turbocharger will be lubricated by pressurized oil-- critically important as the impeller/turbine assembly can spin at speeds in excess of 100,000 RPM.

                                  
                                Basic Turbocharged engine diagram (courtesy of Kellom)

• A supercharger, in contrast, is driven by an accessory belt-- much like the alternator, air conditioner compressor, and water pump. Internally, there are two (sometimes three) lobes that rotate, sucking in air and force-feeding it to the engine. The supercharger makes a very distinctive noise, which can be music to the ears of performance enthusiasts. (Note: a parasitic draw.) (Info courtesy of www.FordsChevy.com)

Cheers!