So I ordered all the springs and stuff i needed to preload my kj's rear bearing assembles it and waaaayyyy tooo tight. shaft would turn but not spin. a little history is i bought all the components i could off an ebay guy. then i found JM Precision and bought their preload spring and a wave washer. after researching their shaft tunnel is extra long so the spring wont work for me and seems too stiff anyways. so i called a known reputable U.S. turbine dealer and they were gracious enough to sell me a shim kit. I always thought the depth of the bearing grove in the shaft tunnel was just to house the spring to preload the outer race to keep it from spinning when the shaft tunnel expanded. but the company that sold the shim kit tells me they only shim to set the height of the compressor wheel. so im confused at the preload theory and also the setup. I also have the version 2 shaft tunnel that i thought i read didn't need preloading but then how does the outer race not spin? if someone could shed some light on the theory i could figure my own setup out based on that. P.S. i do have Kamps book but there's sooo many KJ designs I just need theory of why and i can finish designing my own. Thanks