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Author Topic: Cheap imported hit-miss engine  (Read 455 times)

DJoksch

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Cheap imported hit-miss engine
« on: August 11, 2021, 12:11:52 am »
I bought one of these inexpensive hit-miss engines from China for fun.  Water from the hopper leaks around the press fit cylinder as it runs and the piston rod bounces from side to side on the crank shaft.  This is correctable so I can’t complain for the cost.

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RedRyder

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Re: Cheap imported hit-miss engine
« Reply #1 on: August 11, 2021, 06:47:14 pm »
These are a whole lot of fun for the money.

If you don't put much of a load on it, you won't need any coolant.

I would suggest you consider softer governor springs and retard the timing to at or just after TDC.
To test you can remove one spring.

Have fun!

Gil
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St Paul Steam

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Re: Cheap imported hit-miss engine
« Reply #2 on: August 11, 2021, 09:21:46 pm »
Many, many of us have some version of Jin's hit & miss engine ,they are a lot of value for the money I couldn't/wouldn't build one for his price. Have fun with yours.
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Bruce, St. Paul Indiana, USA
"Originality thrives in seclusion free of outside influences beating upon us to cripple the creative mind."
  Nikola Tesla

70Rcode

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Re: Cheap imported hit-miss engine
« Reply #3 on: August 12, 2021, 04:34:10 pm »
As Gil mentioned,....don't use water or bother fixing the hopper leak....Def not needed for most use..Most focus on getting the basic Running dialed in with a slower speed....A real pleasure 4 the buck experience watching it pop & Miss along!!
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DJoksch

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Re: Cheap imported hit-miss engine
« Reply #4 on: August 12, 2021, 06:56:06 pm »
I saw this engine and could not resist. I think I will make spacers to stabilize the connecting rod on the crank shaft and change the governor springs as suggested to slow it down. My next project is a Breisch Associated model.
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70Rcode

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Re: Cheap imported hit-miss engine
« Reply #5 on: August 13, 2021, 08:53:23 pm »
New engine Loose Con rod ?? ..Haven't seen much of that on these engines !! ...My side clearance rus around 10 thou & all it's  clearances controlled by the 2 brass (or bronze) bearing Shells length & thickness...Custom fabing some new shell inserts might be easy "invisible" fix...
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DJoksch

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Re: Cheap imported hit-miss engine
« Reply #6 on: August 15, 2021, 06:37:40 pm »
I finally decided to correct the rod problem.  The connecting rod was loose on the bearing shells.  After removing the rod cap, I discovered that the bearing shells covered less than 2/3 of the crank shaft. Should be an easy fix. 
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70Rcode

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Re: Cheap imported hit-miss engine
« Reply #7 on: August 15, 2021, 10:23:18 pm »
That would be a good opportunity to drill an oiling hole thru rod Cap & bearing shell for a good pressurized "squirt" of Sae-20 before run sessions.....There's no good assured con rod lube access from facrory....
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DJoksch

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Re: Cheap imported hit-miss engine
« Reply #8 on: August 16, 2021, 09:12:46 am »
Good point.  When I flooded it, fuel backed up into the water hopper so I will address that.  It should become a nice little engine when I’m done.
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70Rcode

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Re: Cheap imported hit-miss engine
« Reply #9 on: August 16, 2021, 05:37:35 pm »
Other than a really bad leaking head Gasket....How does fuel (gas) get backed up into the water Hopper ??
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DJoksch

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Re: Cheap imported hit-miss engine
« Reply #10 on: August 18, 2021, 04:12:41 pm »
I’ll take it apart this weekend and determine the problem source.  I see that the cylinder is pressed into the frame with the hopper.  I think this engine slipped past quality control.
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70Rcode

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Re: Cheap imported hit-miss engine
« Reply #11 on: August 19, 2021, 11:45:28 pm »
Yes,...your's does seem way below par considering all those significant issues...My M-90 arrived about as nearly perfectly machined Functional & cosmetically Blemish free as possible & after nearly 2 yrs of weekly running, Compression is still good & i'm still very pleased with original
 purchase decision...Traditional, basic & required Cylinder/Piston lubrication access issues seems totally lacking & Instruction Manual ignores...I drilled out both Con rod & Main bearing Caps (and bearing shell) with .060" oiling holes & still Debating whether to convert existing top rear cylinder Decorative 3mm cap Screw to Drip Functional by drilling an oiling passage thru steel cyl Liner above piston...That Piston Oiler hole mod would be Highest Risk-to-reward (thoughts of broken off Carbide drill bit stuck in cyl Liner nightmare) Proceedure so far attempted !!!.....One day (after a few cold ones) just gonna get it done !!
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