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Author Topic: Help Making Doll Run Better  (Read 1368 times)

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Help Making Doll Run Better
« on: March 14, 2024, 04:29:58 pm »
The Doll 365 runs sluggishly on both air and steam at what I would consider to be normal pressures (15-20 psi). It never really takes off. It's fairly worn, and I guess that's most of the problem. When I got this engine there were assembly issues which I hopefully sorted out and corrected properly, but those fixes didn't greatly improve performance. There is no obvious binding and the crank rolls easily by hand. The only adjustment I can think of is the length of the threaded valve rods, as the valve eccentric timing is fixed.

The attached videos are at full throttle.

Your suggestions and tips will be greatly appreciated.


Happy Steaming!
 



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Re: Help Making Doll Run Better
« Reply #1 on: March 14, 2024, 05:05:11 pm »
I noticed the inboard eccentric rod and piston valve are canted toward the boiler.

You might try to position it more upright. I suggest doing this while the engine is running. This way you know right away if it helps.

And.. I don't know if will help but it's so easy to try.

It does appear well worn. Try to eliminate any steam leaks on boiler, site glass, valves, pipes, oil cup, etc.

That is as much as I can offer looking down from 30,000 feet.

Best of luck and please keep us updated!

Gil
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Re: Help Making Doll Run Better
« Reply #2 on: March 16, 2024, 02:36:03 pm »
The engine has a definite knock. While stationary determine which journal is sloppy.  I like to take very thin clear plastic to make up the slop. The kind from blister packaging.  Better would be very thin brass sheet or foil.

I suspect your piston rods are worn. A way to check for that is thick steam oil. Dripping some on it, will improve the running momentarily.
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Re: Help Making Doll Run Better
« Reply #3 on: March 17, 2024, 10:57:08 pm »
Quote from: CBWho on March 16, 2024, 02:36:03 pm
The engine has a definite knock. While stationary determine which journal is sloppy.  I like to take very thin clear plastic to make up the slop. The kind from blister packaging.  Better would be very thin brass sheet or foil.

I suspect your piston rods are worn. A way to check for that is thick steam oil. Dripping some on it, will improve the running momentarily.

I have a stand alone 365/1 engine just like this… and mine is also sluggish.  Dropping steam oil onto the piston rod DOES in fact make it run better momentarily, thus what you said, worn piston rods.
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Re: Help Making Doll Run Better
« Reply #4 on: March 19, 2024, 10:39:42 am »
On these older German engines, whenever you see brass piston rods, they're worn.
The nickel plating is worn off. The plating isn't that thick, but with the plating
gone the brass which is softer, wears faster. 
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Tommy

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Re: Help Making Doll Run Better
« Reply #5 on: March 19, 2024, 12:19:34 pm »
Quote from: Woe is me on March 19, 2024, 10:39:42 am
On these older German engines, whenever you see brass piston rods, they're worn.
The nickel plating is worn off. The plating isn't that thick, but with the plating
gone the brass which is softer, wears faster.


Does this cause power reduction because the steam is escaping past the piston rod seal to the cylinder cap?
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The steam engine has done much more for science than science has done for the steam engine.”

― Lord Kelvin

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Re: Help Making Doll Run Better
« Reply #6 on: March 19, 2024, 06:10:35 pm »
It's blow by and these simple engines cannot have the glands packed.  There must be blow by on the pistons themselves.
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