Kato Mikado help needed..

[x600]

 I know there is a few here that can help and it's got to the point that I have to ask.
At a recent show, I had noticed that my favorite Mike had a hitch in its stride and was also running
erratically. My thought was that after 26 years and countless scale miles it might be overdue for a good
service. When I got it on my work desk, I found that one of the valve gear slide arms was broken and the
valve gizmos were flopping around. This was going to take a deep dive into the whole mechanism.
 I'm not intimidated as I have had this engine apart before (although not as deeply) and also have worked on Con Cor Challengers and Big Boys back in the day......
 I managed to get the entire Loco apart, and before reassembling cleaned and lubed all the moving parts, being very careful to note where everything went and the order of assembly. I was able to glue the valve slide part together and even got all the side rods, valve gear and drive wheels back where they belong. the mechanism was tested with a battery before I started to completely reassemble the rest of the body. Here is where the problem arose. The front pilot assembly and the cylinders do not lock in their proper position. The cylinders can move up and down slightly and the pilot deck is floppy up and down. This is after all the related parts are installed. I have another Mike and examined the assemblies side by side to make sure I wasn't missing anything and disassembled and reassembled it several (10-15) times. The Mechanism works fine when tested but the old girl jest ain't right.

To make a short story long, This engine has a great deal of history and sentimental value to me.
 It was from the first run and was a demonstrator back when we had the train store. It also traveled to countless shows and conventions, including San Jose, Louisville and Portland. Sooo... If any of you have any suggestions, pointers, thoughts, or ideas on thread drift, I'm willing to listen.

Thanks in advance,

Greg O.

 

[mike_lawyer]

You shouldn't be able to move the cylinders up and down.  One thing I learned from assembling and disassembling the Mikado is you have to be careful to get the cylinders, pilot, and the part of the frame where the cylinders attach all lined up correctly.  They can easily get misaligned, throwing everything off. 

If everything is aligned correctly, the next thing I would check is if the one cylinder that moves up and down is damaged on the inside. There is a partition on the inside of the cylinder that keeps it in place.  Make sure that is not damaged.

We're you able to get a new slider for the valve gear?  I have extras if you need any.

[x600]

Thanks for the reply, Mike

That explains alot, I didn't know about the partition inside the cylinder.
I'll attack it again tomorrow and see what I messed up.

I was able to ACC the broken slide. It seems to be holding together well.
I'll let you know if it doesn't.

Greg O.

[mmagliaro]

Any chance you can post some clear really close-up photos of the underside where the cylinders and pilot assembly are?
As a matter of fact, more than once I have reassembled a Kato Mikado and had this problem, but I cannot remember what the problem
was.  All I can remember is that it LOOKS like it is assembled exactly like a working one, but it isn't, and this
causes the flopping cylinders problem.   I will try to take one apart tomorrow and reproduce the phenomenon.

[x600]

Here are two pics. one from the bottom, one from the side which shows the Cylinder assembly doesn't meet up with the pilot assembly at the steps. 

The cylinder assembly clearly needs to be lower, but it is sitting on the pilot tabs which is setting on the frame. It appears that it is the same location when I compare with the other engine.

My next move is to check the inside of the cylinder to see if the partition is somehow broken or I am missing something.

Thanks Mike and Max for your help

Greg O.

[x600]

SUCCESS!!!!  I saw the tiny "rib" on the inside of the cylinder that hold the tabs on either side of the Pilot off the bottom of the cylinder. This rib holds the pilot off the bottom of the cylinder leaving a small gap between the bottom of the cylinder and the frame mounting "tab". When I held the cylinder up and slipped the tab on the side of the pilot in below the rib (or partition) on either side, it locked the pilot tight against the frame when the pilot truck assembly was reinstalled. Pointing out the partition was the key here Mike, Thanks!!!!
 After my 6th cup of coffee to calm my jitters, I was able to put her back together and give her a little test run. She's now ready to double head a 50 car hopper train with her sister around the nTrak layout this weekend at the GTS in Puyallup. I hope I don't have to do this again fo another 26 years.

Greg O.

[mike_lawyer]

Great to hear Greg, I was glad I could be of help!  It is easy to get the cylinders misaligned with the pilot on the Mikado, I have done the same thing before by accident.

If the slider for the valve gear ever becomes a problem again, I have new ones in my parts box that I can send to you for replacement.  I keep a stash of extra Mikado parts to service the Mikados I have on my roster.

[x600]

Thanks again, Mike, I'll keep that in mind. Its the grey double rail that the rod slides back and forth on.
It seems to be holding up well.
 I took the two engines out onto the oNetrak "Time Waster" that I have set up so I could run them in together and found out that I put the motor in bass ackwards, so there will be no double heading this time.
 I hate being the same age as old people! 

Greg O.

[peteski]

Ah yes, "senior moments". I'm having more and more of those too. 

As for the repair, that part is made from some sort of slippery plastic.  It is unaffected by solvent cements, and while CA or epoxy might seem to hold the glue joint, I suspect the bond is not very strong.  Plus the glue area is likely quite small.  While I hate to say it, I suspect you will experience another disaster in the future (when you least expect it of course).

If someone offered me a new replacement part from  their stash, I would jump all over that, if you know what I mean. 

[x600]

I have to agree with you, Pete. The part is sort of locked into place so the really isn't much stress on it.
I did the band aid thing because I wanted to get it back together.  I'll put a few hours on it this weekend and that will determine if I need to replace it. I'm wondering how it broke in the first place.

My wife keeps telling me to act my age, nope, not gonna do it.

Greg O 

[peteski]

So what exactly does a person your age act like?  Obviously whatever you are doing is working, so keep on doign what you're doing. 

If you do take it apart again, could you take a photo of the repaired part and show where the break is?  I'm curious to see that. I agree with you that under normal operating condition there pretty much is no stress on that part  Very little friction or force. Is it possible that some foreign object got into the valve gear and caused the extra stress which broke it?

[Lemosteam]

I have to agree with you, Pete. The part is sort of locked into place so the really isn't much stress on it.
I did the band aid thing because I wanted to get it back together.  I'll put a few hours on it this weekend and that will determine if I need to replace it. I'm wondering how it broke in the first place.

My wife keeps telling me to act my age, nope, not gonna do it.

Greg O

If it comes apart again I highly recommend you use UV resin glue instead of ACC.  The nice thing about it is excess can be wiped off before the joint is secured while the the resin is still liquid.  it also allows for perfect positioning, and hardening takes place in a free state so no chance of the two parts moving just before applying the UV light.

[x600]

Thanks, John, I will keep that in mind for gluing delrin parts in the future. For this particular part
I would just replace it, having the opportunity to do so.
 


Pete, here is a photo of the assembly before I properly installed the cylinders.
The two horizontal rail that rod and valve gear slide on are connected as one piece behind the black vertical "keeper". the bottom rail was separated from the top rail at the bottom of the vertical connecting  the two rails. The black vertical piece holds the slide rails in place. I hope I explained it clearly enough.
I can't imagine how it was broken, but the grey vertical bar attached to the slide was out of its upper
slot and hanging down. When I started to remove the entire drive assembly, that's when I noticed the
broken rails.

As far as the age thing, I will be posting an item I built to address one of the problems that many of us
"more experienced " modelers share.

Thanks again for the  input.

Greg O