Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines
The Regular Stuff: Chat, Buy, Sell, Off Topic, etc. => General Discussion - Scale Model Gas Engines - Hit & Miss - Throttle Governed - Non-Compression – etc => Topic started by: DJoksch on August 11, 2021, 12:11:52 am
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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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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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Other than a really bad leaking head Gasket....How does fuel (gas) get backed up into the water Hopper ??
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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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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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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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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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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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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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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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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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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.
https://youtu.be/9QZCkTXffvM