Brass loco throws traction tire... Thoughts?

[mmagliaro]

I know this is an OLD thread, but I have been working on some of these PSC K4's, and I can now attest to the fact that indeed, you can unscrew the center crankpin just by screwing it out counter-clockwise.  You gently turn the eccentric crank
with your fingers while holding the driver still with your thumb.  It is best to get the center driver positioned so
the crankpin is at the dead bottom.   I removed the shell, so the cylinders could flop
around, which allowed just enough play to unscrew that crank without disassembling anything else.

A couple of pairs of tweezers, optivisor, and lots of patience.

You do have to be very careful not to lose the spacers that are on that crank screw.  After it's out, you can slip
a new traction tire right on there and then screw it all back together (another tricky operation best done
with the engine on its side, in strong light, on a white sheet so you won't lose pieces if you slip).
I used a Kato GS-4 traction tire.  It seems to be working well so far (not throwing off and it is getting some
grip).

[peteski]

So, were you able to re-tighten the crank pin with the eccentric properly lining up?  Like I mentioned it should be possible, much earlier in this thread?    Or did you have to use locking compound on the crank pin to properly locate the eccentric?

[Dave V]

Thanks for the heads up.  As I was earlier in the thread, I'm still reluctant to do this, but the Bullfrog Snot doesn't fill the slot evenly and there's a corresponding reduction in traction as well as a slight gallop.

Max or Peteski, I may need some help if I jack this up!   

[mmagliaro]

Indeed, when I put the crank back in, it got very tight right at the correct location, which I expected.
Try to visualize:

- the center driver, with crankpin hole at dead bottom.  The eccentric crank (the short
crank arm that is rigidly soldered to that crankpin)  is pointing straight up vertically.

When I unscrewed it and screwed it back in, it ends up in that exact same position and is very tight, so I'm not
worried that it will unscrew from the hole (although I have not run it enough hours to confirm this).

[kelticsylk]

Dave, I may be late to the party but I tried something similar to BFS with the same results.

Possible solution...
Plasti-Dip can be purchased in a spray can. Not wanting to tear my L1s apart I masked off everything but the rear wheels and with the wheels turning sprayed on an even coat. I wrote it up on the blog...

http://kelticsylk.blogspot.com/2013/10/almost-instant-tractive-effort.html

[peteski]

Max or Peteski, I may need some help if I jack this up!   

Dave,
I think that I can speak for Max and Victor when I say that neither one of the three of us would refuse to to help you fix this loco, if you jacked it up.  Heck, you can send it to me (with the new tires) and I can replace them for you. 

[mmagliaro]

Dave,
By far, the hardest part of the job is putting the crankpin back IN.   There is a spacer bushing under
the head of the crank, and another one between the side and main rods, so you have (from bottom to top):
Side Rod, bushing, Main Rod, bushing, crank.

Getting that little "sandwich" to stand up over the hole in the driver while you get the crank in there and
turn it 1 or 2 turns to get it started is very tedious indeed.  (Bright light!  Towel or sheet so if the parts spill
all over, you don't lose them!)

Specifically, I removed the screw through the pilot truck first (which removes the truck, frees the cylinders, and
basically makes the whole engine come apart, which I'm not a fan of!).  Then the two little screws
at the back of the cab, and off comes the boiler.  Now, you can rotate the worm by hand to get the crank hole
at the bottom.  Grasp the engine and squeeze the center driver with your thumb so it won't turn, and then
use your fingers to turn the eccentric crank counter-clockwise.   It was fairly tight, but I never felt like I was
"forcing" it to get it to move.

Once it moves a little, you can ease it round and round with tweezers.  it will be a little tight at one spot in its
rotation because the rod/link are just long enough to let it go around, but it will go without breaking anything.

Incidentally, this is my first hands-on foray into a PSC K4.  I must say I am not a fan.  The list of horrible design
elements in this engine is long and painful.  But I'll make it go -  one way or another.

[mmagliaro]

Dave,
I think that I can speak for Max and Victor when I say that neither one of the three of us would refuse to to help you fix this loco, if you jacked it up.  Heck, you can send it to me (with the new tires) and I can replace them for you. 

+1
Jack away, Dave.  If you really do get stuck, give me a shout.

[mmagliaro]

After fully restoring this thing to good order (wow, it can run under 5 mph and everything, and with the
original motor no less...)   I'm not impressed by how it pulls.
I lined the center driver TT groove with a strip of masking tape, and put the TT over it, to get a little
more rubber on the rail so to speak.  It did help. 

But it can only pull 6 passenger cars up a curved 1.7% grade.  That's really about its limit.  On a level, it can do more, of course.

Dave, you say yours is a "stump puller".  How many heavyweights can you pull with that thing?

I should also add that I have loaded it up with tungsten and lead so that it's weight is 92g (stock is 76).
The drawbar has been redesigned so it is loose and floppy (no more lifting of the engine from the stiff tender).
The pilot truck spring has been replaced with a longer, very light, flexible one so that the pilot truck
stays put on the rails, actually conducts current reliably, but does not lift the engine.

Springs, links, weight, tire.   Maybe 6 uphill is all I should expect, but I wanted to ask before I bothered.
It does run pretty nice.  When I got it from my customer, it was typical PSC K4 - meaning it wouldn't run more than a foot without stalling.

[mmagliaro]

Okay.... it was just the traction tires.   I put a thin strip of tape into the groove first and put the tire over that.
The GS4 tires are a little too profile for this engine.

After that, it's gang-busters.  Pulled a 9-car up the grade without the slightest slip.

But BEWARE.  The motor in this tiny beast, or more appropriately, the tiny motor in this beast can easily be overwhelmed.
It's rare that I end up with an engine with enough weight and traction that it won't slip before the motor can't take
anymore, but that's the case.   Just watching the ammeter climb, I'm sure I'd kill it if I pulled, say, 12 car trains up grades
on a regular basis.  It normally hovers around 100-125 mA , but it goes over 200 to even 250 with a very heavy train,
and the Mashima spec sheet on this motor actually says the current rating on this motor is only 85 mA.

[Dave V]

Max,

She actually has a Kato GS4 motor in her and with both traction tires doesn't flinch with a full heavyweight train (express box, B60b, 2 RPOs, and 4 sleepers) even in curves.  Since the loss of the tire, forget it.

I've not had a chance to tinker with her recently but I'll give it a shot one of these days.

[mmagliaro]

Max,

She actually has a Kato GS4 motor in her and with both traction tires doesn't flinch with a full heavyweight train (express box, B60b, 2 RPOs, and 4 sleepers) even in curves.  Since the loss of the tire, forget it.

I've not had a chance to tinker with her recently but I'll give it a shot one of these days.

Thanks for the update, Dave.  Once I got good traction tire rubber in my repair project, it pulled great.  I am not remotoring
this one as it would drive the cost up too much for this customer.  A GS4 motor, eh?  Not a bad idea.  I was going to use
a Mashima 1015.    The original motor isn't too bad.  It is just a little underpowered for the high gear ratio in that thing.

[Dave V]

Max,

Sorry to mislead...  Had to go back and look at the e-mail traffic back when Lee and Victor had her under their collective care.  The motor is indeed Kato, but not from the GS4.  It's supposed to be a 5-pole from their "Chibi" Pocket Line traction motor:

http://global.rakuten.com/en/store/mokeiyabigman/item/kato-11-104/

I've not had her apart to see if that was indeed the final configuration.  She went through a number of surgeries before going to work for the Juniata Division.

[mmagliaro]

Well, to finally close the book on these...

I got these two back together.   Ya know, once you fix all the shorts, change out traction tires so it doesn't rock,
fix all the springs so it stays on the track, add lots of weight up in the nose so it has better traction
and doesn't lift up, and fix the electrical pickups, these things aren't half bad.

Unscrewing the cranks and putting GS4 tires on them makes a world of difference.  The key is to put a thin strip of
masking tape down in the tire groove first and then put on the tire, so it has just the right height for good traction
without making the engine rock.

These are just with the original motor and with the original half-axle pickup system in the tender.  I wish the motor had more
torque, but I was trying to
not do major surgery on these.   But with a little pulse in the DC power, they can run well under 5 mph  (which implies that
on DCC, they would also do it)

[peteski]

Well, to finally close the book on these...

Not so fast Max - Dave still hasn't fixed his loco, and this thread was started for Dave's ailing model.