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

hink

I have seen posts about this happening before any shop that is putting mallory on those holes shouldn't be balancing cranks thats for sure, There is only one way to put mallory in a cranks so it don't fall out!!

Costs money to go to school !!!!!

Here is the way we install mallory

fast75vega

X2......very well said

TRChassis

I agree this guy shouldn't be balancing stuff like that but he is a pretty big liar with a bigger ego. If I knew how to post the pictures it would really show how bad of a job he did. He says it is not his fault and said our tune-up caused the problem. I am out quite a bit of money but I have learned my lesson, and will go to either Sunset racecraft or Ohio crankshaft. This worthless lying machinist over here took about 7 months and charged about as much as those shops I mentioned. We are in a part of the country where good machine work is hard to find. Thanks for your post.

Rick

hink

Rick email me a pic and I will post it for u

hink

Here is a pic Rick sent me to post

TRChassis

Thanks Carl,
If it saves one person from getting the shaft on a deal like this it will be worth it.

Rick

zetagoat

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

TRChassis

It does look to me like he ground it off to the point that nothing except probably a piece of weld like tin foil was holding that part from coming out with all the centrifical force applied to it. Like I said the engine builder has an ego bigger than the moon so he will never admit he messed up but it is obvious he did. I have seen cranks balanced the way he did it but installed and welded properly as you said, he made a mistake but will not admit it. I made a mistake by taking it to him and should have gone out of town for sure. He was a friend but no more, money paid can be recovered but time + lost and track/race time lost can never be replaced.

Rick

hink

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!!!!