British 0-4-0 Toy Locomotive: he said

[spuddevans]

Keep at it Zee, we're all routing for you.


On my Paddleducks build, when trying to get it running I found that the key for me was to identify and cure as many points of friction as I could.

I know you will get it going, just stick at it a little at a time.


Tim

 

[hobby]

Succesfull build so far never the less, when I built my first engine, I had no idea what was binding or why, it didn't feel like anyuthing was binding, it spun freely, and the timing was set on, but a last ditch effort, I took 3in1 oil, and lubed everything that was making contact and every concevialble pivot point, and then it began to work more aqnd more smoothly to the point that it actually started running, if I knew that, I wouldn't of had to rebuilod the valve 3-4 times.

Did you give everything a good oiling?

 

[zeeprogrammer]

Thanks Pete, Tim, and hobby.

I've used oil...different types at different times. Maybe sometimes too much.

So long as there's a question to answer, I'll keep at it. (Well...up to a point. If I have to machine new cylinders and pistons...I'll probably put it aside. Heresy I know but I just don't have the time and my anxiety to move on is starting to boil over. ;D )

I certainly see steam...and there's been improvement each step of the way.
No 'good' reason why it can't go.

There are 3 areas I'm looking at next...

Safety valve. Least likely. But maybe there's a leak that's preventing pressure to build. I don't see anything coming out though.
Phasing of the drive wheels. Possible. It's not near enough to 180.
Binding at the crank pins. Most likely (I can sometimes see it as the wheels stop).

Sorry for the plodding...thanks everyone for hanging in there with me.

 

[kcmillin]

Zee,

have you tried putting less water in it?, giving it more space to store the steam that is being created.

Kel

 

[shred]

I have no adjustment on the pivot pin springs. You just tighten the pivot pins down until the end seats against the frame. Having said that...no one can accuse me of having perfectly concentric pivot pins that fit the perfectly concentric holds in the cylinders.

I was thinking the springs that hold the cylinders to the port blocks, sorry.

Anyway, in the spirit of step-by-step debugging, step 1 should be "how much steam pressure is there?". If the answer is "enough", then you can move to debugging motion problems. If there's not enough, you need to fix that before the motion parts will even try to move, no matter how perfect they are. Any old hardware store pressure gauge can work, just put a loop or u-trap in the airline so it doesn't get blasted with live steam.

I know, it's a pain in the rear to faff around with gauges and plumbing when all you want to do is run the thing, but after resisting and pulling my hair out for days, I finally broke down and did it, it turned out to be vital to getting my little loco running.

 

[zeeprogrammer]

Thanks Kel. What I need to do is fill the boiler full, then dump it into a graduated flash so I can measure how much it holds. (Really Zee? Couldn't you just calculate the volume? It's just a cylinder. Sheesh.)

Shred...right...the springs that hold the cylinders to the port blocks. But the pivot pins only go in so far. The pivot pin has a head to it that is larger in diameter than the part that goes through the spring and then the diameter drops further to get through the port block. Then it ends with a screw for going through the frame into the stretcher. That last diameter I mentioned is larger than the hole in the frame so it stops there.

What I was referring to was the head. It's only about 1/16 thick. If there's too much play between it and the cylinder then I think the cylinder can 'wobble' against the port block. That would create a space between the port block and the cylinder and let steam leak. Why I don't have this problem with air (if it is a problem), I don't know.

If I get a chance, I'll run by the hardware store this afternoon (while making a wine run).

just put a loop or u-trap in the airline so it doesn't get blasted with live steam.

Ah! I had wondered why I see loops on pipes feeding a pressure gauge. Thanks for that.

 

[zeeprogrammer]

A little video showing the cylinder to port block and crank pin.

Thanks to Costner for lending the voice...but he got the script wrong. First reference to 'crank pin' should be 'pivot pin'. :big: That's what happens when you pay in beer.

 

[Deanofid]

I thought it was William Hurt..

I don't know why it would make a difference on that part in the binding department, whether it ran
on air or steam. (I mean I really don't know.)

I can't help thinking it just hasn't got up to steam pressure, but I've lost track now. Has it made
enough to pop the safety in your testing yet?

Dean

 

[bearcar1]

I thought it was William Hurt..

:big: :big: :big: :big: :big:

Frazier Thomas ? ! ? ;D

Z', were you able to obtain a pressure gage on your 'refreshment run'? I have to agree with Dean, it just seems like there isn't enough 'poop in the chute' (as they say in farm country)


BC1
Jim

 

[zeeprogrammer]

Hi Jim n' Dean...heh heh heh

I thought it was William Hurt..

Frazier Thomas ?

I said who it was. But thanks...that should cost me less beer next time. :big:

.................

Yes...I got the pressure gauge...not that I needed to. (re: Shout).
But I lack tubing. Fittings I can probably make. But I haven't taken the time to figure out how to connect everything so there may yet be a surprise for me. (Goodie...I like surprises. Don't you? ;D )

Tried looking for some tubing at HD today...but diameter is too big I'm thinking.

Celebrating grand-daughter's 1st birthday tonight. Tomorrow, 'she' has me going to a tile store. Then it's off to work work.

This is not going as planned...

 

[doubletop]

Zee

I'm on the 'you need to check the pressure" team If you've got a digital thermometer you could use that to measure the pressure. Maybe make a modified steam dome with a gland to get the probe securely inside the boiler.

Steam tables

Temp - PSI
Deg F
212.00 - 0.0
216.32 - 1.3
219.44 - 2.3
227.96 - 5.3
240.07 - 10.3
250.33 - 15.3
259.28 - 20.3
267.25 - 25.3
274.44 - 30.3
287.07 - 40.3
297.97 - 50.3

If your meths burner isn't chucking out enough heat somebody has already suggested you could give it a hand with your gas torch and get the safety to blow.

Those pivots look free enough you are going to be able to rock them like that, its the way they work. The crank pins not being exactly 180 out is a red herring I'd say 180ish should be fine. Put the wheels with the pins at top and bottom and not at the end of the strokes. If its got enough pressure they should at least kick a bit.

So more heat required

(it occurred to me do you have Meths in the US? That denatured stuff sounds like its been neutered and has no lead in its pencil.)

 

[Deanofid]

DT;
Denatured alcohol is what methylated spirits is called in the U.S. Denatured doesn't mean "neutered".
I don't know where that idea came from. It means it's been made un-drinkable. Ethanol with enough
methanol to make it poisonous.

Dean

 

[doubletop]

DT;
Denatured alcohol is what methylated spirits is called in the U.S. Denatured doesn't mean "neutered".
I don't know where that idea came from. It means it's been made un-drinkable. Ethanol with enough
methanol to make it poisonous.

Dean

Dean

Sorry was meant to be a bit tongue in cheek but that must have got lost somewhere across the Pacific ;D

Pete

 

[Deanofid]

Ha! I thought you were serious, Pete. -Natured.. neutered. Kind of sound alike.
Good joke, once it soaked into my tiny brain! ;D

Dean

 

[Blogwitch]

Zee,

When you build engines, most will run on air quite merrily. Put steam to them and things go bottoms up.

The first things that I adjust or look at when that happens is the pivot points.

Everything has to be perfectly square, say the crank pin to the wheel, the big ends to the crank pin, is the hole thru the big end exactly square?, is the cylinder face square to the big end hole?, is the port face exactly square to the crankpins? Another major thing, when the port faces are working together, the angles can change as the port faces separate slightly during normal running, so you have to build in a slight allowance for that. The way I do that is give a couple of thou clearance on the big end to crank pin, in other words, a slightly sloppy fit.

You will find that these things are not really super critical when running on air, but as soon as the hot stuff is introduced, even a tiny deviation from square will cause untold problems.

I had the same problem with a batch of engines I made, they ran fine on air, on steam they locked up. It was eventually traced to the big end holes being about 2o out of square. It was then that I made a jig that guaranteed squareness, and remade 12 big ends. The engines then ran perfectly.

Just a suggestion.


Bogs

 

[zeeprogrammer]

I'm assuming we're talking about setting a gauge to the complete system. Right? Not just the boiler. If just the boiler then I'm testing the safety valve. I did that with the mountain shock bike and placed the boiler under water so I could check for leakage. (That's not to say I messed up since and the valve needs rechecking.)

So if the gauge shows insufficient pressure...then it's a leak(s) or insufficient heat.

If it's a leak then it could be the safety valve, the port block to cylinder junction, or the piston. But if it's a leak...then I think air at low psi wouldn't have run the engine.

If it's insufficient heat...then I'm thinking flawed design and I'll be ***.

If the gauge shows sufficient pressure...then it's binding. And the most likely culprit are the crank pins. Maybe pivot pins...

Another major thing, when the port faces are working together, the angles can change as the port faces separate slightly during normal running, so you have to build in a slight allowance for that. The way I do that is give a couple of thou clearance on the big end to crank pin, in other words, a slightly sloppy fit.

That's where my thinking has been the last several days.
Thanks Bogs.

 

[shred]

I'm assuming we're talking about setting a gauge to the complete system. Right? Not just the boiler. If just the boiler then I'm testing the safety valve. I did that with the mountain shock bike and placed the boiler under water so I could check for leakage. (That's not to say I messed up since and the valve needs rechecking.)

So if the gauge shows insufficient pressure...then it's a leak(s) or insufficient heat.

If it's a leak then it could be the safety valve, the port block to cylinder junction, or the piston. But if it's a leak...then I think air at low psi wouldn't have run the engine.

What you're really wanting to test is the steam generating ability of your burner versus the leaks in the system.

Not only can it make steam, but can it make it faster than it gets used or leaks out. Air from the compressor is about infinite, so it can refill what leaks out almost instantly. Getting it to run on low pressure is the first step- the second is running it on low volume.

The meths burner is pretty tried-and-true, so I think there's probably not a fundamental design problem. I suspect you'll find a leak/fit problem somewhere, but this debug flowchart starts with 'is there enough steam?'.

You might also try putting 5psi air into the system and sinking the whole mess in a bucket of water and seeing where air leaks out as well.

Another thing to try would be hosing down all the joints with soapy water once you have a fire up for several minutes.

 

[zeeprogrammer]

Not only can it make steam, but can it make it faster than it gets used or leaks out. Air from the compressor is about infinite, so it can refill what leaks out almost instantly.

That makes it clear for me. Thanks shred. I think I knew that but didn't pay it sufficient attention. If it's leaks, it's the safety valve, port faces, or piston. I sure hope it's not the piston.

Is it also possible that I'm too quick to make it run? By spinning wheels and rolling on track could I be letting the steam out before sufficient pressure builds? I had noticed at one point that after letting it sit a while I was getting good steam (leaking from the ports but by that time I was afraid I was running out of water and shut things down).

 

[arnoldb]

Is it also possible that I'm too quick to make it run? By spinning wheels and rolling on track could I be letting the steam out before sufficient pressure builds? I had noticed at one point that after letting it sit a while I was getting good steam (leaking from the ports but by that time I was afraid I was running out of water and shut things down).

That sounds like what you could be doing wrong Carl. Fire it up and let it sit a while - till you hear the hiss of steam coming from the ports or the safety valve. Then push it slowly forward and backward - just two or three inches at a time; at that point you may get water coming from the exhaust because of condensation in the cylinders. Once the water clears from the cylinders it might take off and run.

Good Luck!

Kind regards, Arnold

 

[kcmillin]

I agree with Arnold 100%.

That water you see is normal, as far as my experience that is.

When the boiler is reaching temperature there is condensation in the steam lines and cylinders, along with the splashing water in your boiler there will be some water.

How much water are you putting in the boiler? Don't quote me on this but I think there should be at least 40% of the boilers volume reserved for steam storage.

Think of your "Little" air compressor's tank, and then compare it to your little Loco's boiler, then think of how quick your air compressor cycles when your running it on air.

That little boiler has a big job to do.

Perhaps someone with more experience in the matter can "Shred" some light on the water to air ratio of the boiler.

Kel