K-line question for the old-timers

[mpzpw3]

I have an MP-15 engine from K-line, that I bought probably around 1989. It is a pretty good runner, but the shell "wobbles" on the frame considerably. Back in the day, I remember the magazines had a fix for this, but can't remember what it was. Seems like shims or washers were used between the trucks and the frame, but not sure. Does anyone know how to fix this problem? It is a nice running engine, just wobbles something terrible.

[ADCX Rob]

The truck mounting posts need to be shimmed from inside the loco to tighten them up some.  Most of the wobble, though, is from the wheels/traction tires.

Rob 

[otftch]

As in the previous post install a small flat washer under the clip that secures each truck.Don't make it so tight that it doesn't turn freely.I've also glued a piece of foam rubber on each side of the top of each truck to absorb some of the motion.Again not a large piece.It will wear off eventually but if you inspect it occasionally you can catch it before it comes apart.NOTE;the later trucks have a small bump on each side on top of the truck to help this wobble.I glue the foam right on this bump.

                                         Ed

[brianel027]

It isn't the shell that is wobbling, but the frame itself on the trucks. The sheet metal frame hasa downward indentation where the hole is that the truck mounts into. There is a metal piece from the truck that inserts into the hole and is held in place with a "C" clip washer. There is also a curved slit cut into the loco sheet metal frame, where a folded "guide pin" from the truck slips into this slit.

To cure the wobble you can use a thin washer between the frame and the "C" clip washer to tighten up the play here which can cause wobble. You'll have to experiement here to find a washer that tightens this up while allowing the truck to still pivot freely.

Also be sure the "guide pin" is clearing the curved slit and not rubbing against it at the far ends. You can also insert a spring with a washer on top of it over this "guide pin" below the frame, between the truck top and the bottom of the sheet metal frame. I use springs that I pulled from an old junk computer keyboard. The washer helps to keep the spring from working itself into the slit.

The spring over the "guide pin" may help reudce wobble, and will absolutely help reduce derailments from the front truck when the loco is pulling a long train.

Traction tires will not cause this wobble, unless they are well worn or improperly on the wheel. K-Line over their history had the traction tires all over the place: on both wheels of the same axle, on differing wheels on the same side, and diangionally one of the left wheel and another on the other axle on the right wheel. I typically remove one traction tire from each truck and re-adhere the other traction tire with 3M carpet tape. Removing a traction tire will help reduce slow down and engine "growl" noise on tight 027 curves. If I add weight to the loco, I may remove all but one traction tire.

On the point of traction tires, these locos with DC can motors in the trucks (be they Lionel or K-Line) are made by Mabuchi and though they are decent motors, may not necessarily run at the same precise speed. When you have two motors that behave a little differently and then have traction tires on two wheels on both trucks, this can also help cause more locomotive "growl" noise on curves. On the Lionel MPC locos with a single open frame AC motor, the traction tires are on the same side of the truck on each axle.

Even removing all traction tires and leaving the wheels as is with the traction tire groove in the wheels will not cause wobble, though it can cause some bouncing due to uneven track or over switches. All my Lionel Industrial Switcher locos have the single traction tire removed. But I add a substantial amount of added weight to these. I'm amazed at how well they pull now, even without the traction tire - but the added weight helps with this.