Re: DSNG 476 and 478 status

Jon Walden Wrote:
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> Russ, John and Earl all explained the concepts of
> and pros/cons to the split bushing design that was
> once very common. This thread referred primarily
> to the crank pin end of the main rods, but the
> concept was the same for the wrist pin. I should
> clarify that the wrist pin end does not use a
> floating type bushing, but rather a simple pressed
> fit brass bushing.
>
> [ngdiscussion.net]
> 11148#msg-311148
>
> Replacing the split bushings for the wrist pin is
> not a concept put into motion by the D&SNG. The
> D&RGW had begun the process long ago. The main
> rods for the 473 are both stamped "Oct 1943.
> Burnham". The left side main rod for the 476 is
> also designed without a split bushing. It's a
> process we have simply continued as time and funds
> became available.
>
> -Jon

If I recall, about 1/2 the main rods in Chama are solid bushing rods. The rest are set up with for split bushings. When I first went to work in Chama, we were trying to make them "adjustable" and the result was lots of wristpin noise. They simply would not stay in adjustment. Eventually we came up with the "re-usable" bushing idea, where the bushing was bored to size initially, then when worn out, it was split, the center milled down, a new pin diameter bored and back in it went with the wedge always drawn up tight. No more banging. The added advantage of this type of wristpin bushing is if you need to adjust the length of the main rod you can shim on either side of the brass. On the solid brass rods, you have to machine an off center bushing if you need to adjust things.