Crank walk?

[myneon]

I saw some guys on another site discussing crank walk in regards to turbos. Can anyone here explain to me what "crank walk" is? I would have asked one of them but did not feel like going through the process of registering at yet another message forum. Thanks for any help!Later!

[TheCamel]

Crank walk describes the movement of the crankshaft within the block along the bearing journals. Instead of just rotating as normal, excessive crank walk moves the crankshaft against the journal on non machined areas of the crank. Basically this is ussually taken care of ny adding a different sized thrush washer on the front of the crankshaft, as this washer begins to wear the crank begins to move forward and back along the crank journals causing excessive bearing wear and leads to crankshaft failure. The rotating mass of an engine is really a feat of engineering, and a slight vibration, detonation, or other outside force can cause this to happen prematurely. Worst case scenario is that the rotating mass begins to put undue stress on the main block journals, the connecting rods and wrist pins. In the case of most import engines the rotating mass is spinning roughly at 7000-9000 RPM at redline whereas the V8 boys are spinning roughly 4500-6500 RPM, as you can see the spinning inertia of each engine is different, now adding a turbo to these engines creates even more stress, and stress finds the weakest link. Think of pistons as the most clausterphobic thing in the world, they are trapped within the cylinders and looking for a way out. They attempt to escape through the valves only to be pulled back again by the crankshaft. As the crankshaft wears out the pistons and conecting rods lose their grip on them, and BOOM the piston finds a new home, along with the engine oil and the coolant. Now Murphys law has some play in this too, because it ussually happens at the least oppertune moment. I hope this gives you a better understanding on what you were asking, I know it is vauge, but its the best way I could explain it in laymans terms.

TC

[myneon]

Thanks man I appreciate the reply. I think I have a pretty good understanding now.