Crank pilot concentricity
Is there a tolerance for concentricity of the pilot at the rear of the crank? I set the forged crank from my 340 up in the lathe to check it out and make it a little easier to polish the journals. Before doing that, I turned an T-shaped insert with a center pilot to go in the bronze bushing on the back end of the crank so the center in the tail stock could support that end. The insert was a snug slip fit in the bushing which seemed to be like new inside. Dialed in the snout end to two tenths run-out on the #1 journal. I am getting .006" run-out on the #5 bearing journal, which seems to be a touch high. This is saying that the trans pilot is not in the center line of the crank. There is maybe 1-1.5 thou max from the setup. I don't have a steady rest to support the tail end by the bearing journal so I'm working with what I have. Crank has been ground 10-10 and I wonder if that maybe contributing, if it wasn't centered when ground?
Is this enough run-out to worry about, if it is truly there? I'm going to be putting an A833 behind this motor when it goes back together.
Is there a tolerance for concentricity of the pilot at the rear of the crank? I set the forged crank from my 340 up in the lathe to check it out and make it a little easier to polish the journals. Before doing that, I turned an T-shaped insert with a center pilot to go in the bronze bushing on the back end of the crank so the center in the tail stock could support that end. The insert was a snug slip fit in the bushing which seemed to be like new inside. Dialed in the snout end to two tenths run-out on the #1 journal. I am getting .006" run-out on the #5 bearing journal, which seems to be a touch high. This is saying that the trans pilot is not in the center line of the crank. There is maybe 1-1.5 thou max from the setup. I don't have a steady rest to support the tail end by the bearing journal so I'm working with what I have. Crank has been ground 10-10 and I wonder if that maybe contributing, if it wasn't centered when ground?
Is this enough run-out to worry about, if it is truly there? I'm going to be putting an A833 behind this motor when it goes back together.
