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Advice needed, Brand New C-18 tractive effort

4496 Views 64 Replies 14 Participants Last post by  RioGrandeFan
I have one of the early delivered C-18s from Accucraft.

I have steamed it inside on my garage layout at 50F and on my newly completed outdoor layout at various temps under 40F. For each temperature and layout I have also used the same consist behind my slightly modified Ruby.
I'm a little disappointed in the C-18 compared to the Ruby. But it comes down to 2 things that can be addressed but I need advice from experienced steamers.

The first being steam, it will produce steam, and pop off. But it will run low of water if I leave the bypass open and will have to stop for a few minutes to steam up again after pumping in water again. If I close the bypass to an appropriate position to maintain water, it will barely stay above 20 psi, due to both the drag of the pump and the cool water going into the boiler. This performance was seen on treadmills too.
The first attempt to remedy this will be to check that the jet isn't plugged. I'm suspicious of this since there isn't much reaction to valve position past 1/2 turn. This is ceramic burner. I've used Butane normally and recently tried switching to isobutane. Besides cold weather gas pressure, I never saw an increase in steam from either engine. Anything else to check?

The second part of tractive effort after horsepower is traction. On the occasion that I have a full boiler, water pump in bypass, and steam to 60 psi. When I open the throttle I get lots of wheel slip with not much acceleration. With the same consist behind my Ruby, it will do a burn out, spinning the drivers as fast as it can. But the whole train accelerates at almost the same speed as a controlled start with no slip. Once it's moving about half cruising speed the wheels will grab again. I know one solution is to add weight to the engine, but it already weighs more than twice the Ruby so the weight per driver should be similar. The only other question could be the wheels, my Ruby has 2 1/2 years on it. Does that wear on the wheels give it a better grip than the brand new C-18 wheels? I am being generous with the oil on links and eccentrics and bearings, but the oil on the drivers should be no worse than the Ruby, and I try to keep the rolling surface of the tire clean.

Thanks for any advice.
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I would be very interested in what yours looks like, does your brick glow, do you have gaps around it? How far do you end up opening the gas valve?
Here are the only pics of the fire I have. Tomorrow I plan to fire it up. I’ll be sure to take better pics of the fire.
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Your gaps around the burner don't look too far different from mine. But my brick never gets that color. No matter what method I try.
I don't think there is any difference in our locomotives at all. You have a gas flow restriction somewhere could be jet, debris in the gas lines, the brick, kink/bend in gas line or maybe the gas regulator valve on the tender. I know when I push down slightly on my gas regulator when fire is lit it will almost go out.

Has your fire ever been stronger since owing this loco?

I am not sure how far I open the gas valve. I open it until I have a nice strong blue fire maybe half turn. Tomorrow I will check that. I have been meaning to put indicator line on the knob so I can keep track of where it's at.
Here is my fire. Sorry there are so many pictures it’s quite the challenge to take good pictures of the fire.
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Thank you so very much!
That shows me exactly what I'm up against.

Looking back at my pictures from when I tested my burner on the bench, I never had the blue cones across the whole tile. At best I only had half the tile with cones. And at that my gas valve is wide open. I've been running with half the burner you have.
My new jets will be in a day or so. Once they're here I'll purge the whole gas system and test everything.
Push down the Gas regulator...
3 of my Accuctaft regulators have the same vertigal play
I installed a coil spring underneat which took care of the play
Push down the Gas regulator...
3 of my Accuctaft regulators have the same vertigal play
I installed a coil spring underneat which took care of the play
I would think gas pressure would push the needle valve up. I do notice a decrease in gas if I push the knob down, but it come back when I release. Or is there a floating seat that is picking up and the spring would hold it in place?

In my previous post, when I said gas valve wide open, I should have clarified that I was 4 turns out past where the flame stopped getting bigger.
I have my new jets.
I believe that solved the problem of making sure my engine has the capabilities it needs. Unfortunately though it now effectively resets my progress as a fireman for this engine and I have to relearn it all.

If I turn it down low the ceramic will start to glow.
It is also making a crackling sound because the flame is not stable.
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If I turn it up any it will get the little blue peaks and stop glowing.
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If I turn it up a lot it looks like this.
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I may pull the gap seals from beside the fire brick to see if it behaves different.

It sure looks like the jet was the problem.
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I think our fires look similar now. Glad to see it’s firing better.
I look forward to hearing if you can now keep the pressure up along with the performance.
Looks a lot better, though that white hot spot is concerning. Maybe need to diffuse below the brick some to balance it. How is the steam rate when its on a medium flame? If runnign wide open you will find yourself out of gas real fast.. I would expect no less than 35-40min runtime for that large of a a loco.
Last time I ran mine it took roughly 8 minutes to pop off pressure at this point I killed the fire, topped off the gas tank, re lit the fire and ran for 50 minutes. I was quite impressed with the run time.
Saturday two experienced steamers are coming to visit. Since the equipment is doing the right thing now, maybe I'll get some real performance with experienced hands at the control.

As to the fire diffuser, this burner is constructed with an open box, two solid brass rods about 3/8 inch diameter, on the center line at the 1/3 spacing is what the ceramic sits on. In the picture the forward one farther from the jet is visible as the dark spot. The near one is the first thing the jet hits and is right behind the bright white spot.

I should figure out a diffuser since the first half inch of ceramic never has any flame, the jet blasts right past.
I've been meaning to ask you, on your c-18 does your blow down on the sight glass leak? no matter how tight I close mine it leaks.
I finally ran again after all my recent attempts to improve burner performance.
I only ran in my garage with an ambient temp of about 60F (turned up the heat since I had guests).
While the performance was an improvement for me, my guests being experienced steamers with previous Accucraft Butane models were disappointed with the steam production. The telling observation for them was that while they usually have to make an effort to manage the burner to avoid blowing the safety, I have to stop and make an effort to build steam to pop off.

Their observations were that there is room to grow the ceramic burner in width, eliminating the need for filler material to plug the gaps, and that a diffuser may be needed to help the fuel and air mix more readily and evenly in the burner.

Another observation, this model has all of the elements that would make it favorable for alcohol conversion. The tender has 1/3 of it's body empty in the back, plenty for a fuel tank, has a blower, and what looks like a hole under the foot plate meant for the wicks tube.

I will continue to pursue getting this engine to fire nicely on gas, I may venture into building a new ceramic burner entirely. once I've achieved that, I may set this engine up to duel fuel. having the option to switch between Alcohol and butane just by switching the burner for the wicks.

My sightglass drain doesnt leak until I use it, then I have to reef it tight, it drips for a while but eventually stops.
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Go to some of 'billie 1906' older posts as he has loco builds with ceramic burners and has info on diffusers. I think he is your man for info on getting ceramic burners to operate right.
Mine doesnt pop off as frequently when I have my boiler on the full side. I am finding out mine performs best with half or a quarter full sight glass.

I still think Accucraft should have had a coal option just like they do for the C-25
Correct. We discussed that when examining the loco. The C-18 is the only gas-fired engine that I know of that was built for butane only operation that has a blower as part of its design…You think the Acc engineering group might have gotten a clue that their burner design perhaps needed revision based on that fact alone! Bill’s diffuser design requires no fan nor do I remember seeing a blower on any of his or Bowande’s engines for that matter. We suggested to shamelessly copy Bill’s design and/or redesign for dual operation with alcohol. I would defer the design of coal operation to Rob Lenicheck or someone of equal expertise to assess feasibility of that conversion.

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In looking into the burner issue I discovered a stainless flame baffle in the firebox. What is it's purpose? Is it to protect the crown sheet from the burner's direct heat? Could a ceramic burner melt the solder if the water level gets too low if not for this baffle? Or is it meant to force the flame a certain way to try an extract more heat?

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Item 27 in the drawing.
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While looking in the firebox, it appears that the top of the crown sheet is right under the throttle fitting. I never took any measuring tools out, but I would be leery of letting the water level linger below 1/3 sight glass on my loco.
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I am very interested in the purpose of the baffle as well.
Are you running blended fuel or just butane?

As far as the water level goes I deff hear your concern. The first few times I fired my c-18 within ten minutes I killed the fire because I was so nervous as to how much water was actually in the boiler vs what the sigh glass was telling me. My sight glass was very inaccurate. Since then I have drilled out the banjo bolts and seems to have really helped but I still don't really trust the glass. I've been told as long as you have water in the glass your good but if your on the low side you really need to baby sit. I have also learned how my locomotive sounds and performs with a full boiler and when water is getting on the low side. When my boiler is on the lower end I'm popping off pretty frequently and when popping off its pure steam, when my boiler is on the full side I can hear it from the stack and rarely pop off unless I close the throttle but when it does there is a good amount of water shooting out along with steam.

The manual says "If the level drops lower than the top of the water gauge nut, stop the engine and use the hand pump to add water."
My question is and may be dumb but where is the water gauge nut? I kinda thought the water gauge had a upper and lower water gauge nut? Hopefully someone can chime in here, I am still a noob.
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