Originally Posted by zetagoat
Originally Posted by TRChassis
Just wondering if anyone else has had an externally balanced 4340 crank balanced to internal specs and have the heavy metal fly out of the crank on the 11th pass. The machinist, if you want to call him that welded the piece into one of the normal balance drill holes not sideways on the counterweight like I have seen. Anyway the piece (1.5" long by 1.0" dia.) came flying out at 6,500 RPM through the pan, the diaper caught it but all 8 quarts of oil also exited and the motor seized, and is a total loss (BBC 496). The hole in the pan is almost 2.5". The machinist told me he had done many of those, and said we must have done something wrong. I wonder what we did wrong except for going to this lying, cheating machinist who took about 7 months to bore and balance our motor to start with. Any opinions?
Rick
You can install heavy metal vertically w/no problems @ all even in worst conditions it should never come out. Your guy did several things wrong, 1. he should of at the least, blended the outside edges with a tig or mig so that the corresponding metal would be attached to the edges all the way around. A tig works best because you can really put the edge in well and it looks good. 2. he just piled the mig on top and if you took a chisel you could knock the weld off the tungsten. 3. he thought he could weld tungsten with a mig, don't work. 4. I use a drill and ream fit, usually .003-.004 press fit the tig weld the outside edge over really nice. this is ofcourse if I have to put heavy metal in vertically. The ideal and proper way is to do it horizontally
When we press mallory in it only has .0015 to .002 press and it goes in some hard and your pressing mallory in with .004 press!! I would have to say with that much press it going to take alot of tons to get that in place and that being said you are going to bending the crank cause there is no real good way to support a crank pressing the mallory on the OD of the counter weight.
I don't think you would ever press a wrist pin is with .004 press!!!!