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Discussion in 'General Engine Discussion' started by minh-thanh, Jul 19, 2018.
Thanks Mechanicboy !
I'm doing it again. Maybe it would be better...
Very interesting book ,thanks for sharing.
I has the book i bought a lot of year since.. then i build the first glow plug engine and later model diesel engine of my own construction and from some plans.
Common novice errors are the design of transfer ports and exhaust ports that do not work efficiently that the engine is very difficult to start up or loses a lot of power when the engine is running. I would recommend Scnuerle porting system fig. f and fig. g (fig. g: the boost port is lower than two other transfer port) or exhaust on both sides and transfer port front and rear fig. d which works best for first model engine builder. I have experienced it from my own mistakes when I designed transferport / exhaust ports.
And much easier if you have a reed valve in the back cover where the carburetor is mounted on back cover since timing is not critical (timing is fully automatic). The reed valve is locked with spring lock ring same as Cox engine to example. The reed valve can be made of plastic sheet or beryllium copper sheet (difficult to buy, then i used the plastic sheet as valve, last very well). Rotary valve in the crankshaft also works very well. If you want to make engine with reed valve, ask me then i give you a plan of back cover with reed valve.
Reed valve is fairly simple to make. I make it experimentaly from 0,05mm steel and plastic foil with same result.Engine with RV have very good starting ability ,but it have one minus.It often start running in reverse direction.
Hi Mechanicboy !
That's Great !
Please send for me : firstname.lastname@example.org
Many thanks ,Mechanicboy !
Minh Thanh, e-mail not necessary.. I'm showing the photo and drawings of reed valve. It's not difficult to create the back cover with reed valve as you see at my drawings. The engine can run in both ways also you can use the engine as traction or pusher in the airplane to example.
The engine was my first diesel engine, created on Unimat Emco 3.
Crankshaft from shock damper from car. Crank case cast from old water pump for car. Piston from camshaft (cast iron), cylinder from drive shaft (high tensile steel).
You could fit bronze front bearing, lap crank shaft to it
Thank you for your pictures ! They are clear and easy to understand
Thank you very much !
Keith whiddett !
Thanks for your suggestion.
I will try to do well...
The way the fuel is going into engine isn’t your problem. You are losing crankcase compression through the front housing. Fit bronze bush to front of housing and lap it to crankshaft don’t worry if it’s a bit tight it will bed in. Do you have electric starter? To turn engine over fast this will help. Do you have good compression? Also the porting in cylinder must be correct to the drawing.
Hi Keith whiddett !
- The way the fuel is going into engine isn’t your problem : yes . But I'm thinking: I'll try to do everything as plan (I'm not sure because it depends on what I have, the machinery, my experience .... ), if it's not running I'll follow the Mechanicboy's scheme on the reed valve, I just need to adjust the back cover with the reed valve. I need it to run, and when it runs I will understand more about it...
- You are losing crankcase compression through the front housing. Fit bronze bush to front of housing and lap it to crankshaft don’t worry if it’s a bit tight it will bed in : That's a good suggestion.
- Do you have electric starter? To turn engine over fast this will help : yes , i have electric starter
- Good compression :yes , it has compression, but I don't know how to determine good or not? because it was my first engine
- the porting in cylinder must be correct to the drawing : I will check it again.
Thank you very much !
Remove glow plug and connect battery it should glow bright orange. I think the fuel going in to engine might be blown out though front bearing because because fit not good enough. It should go into crankcase and blown up through the ports. Be carefull with starter it can bend con rod if you get to much fuel in cylinder
Bit more done today, all day doing crankshaft and propdriver!!!!
Hi all !
Can I use the this fuel for my engine ?
Yes, it's this as model glowengine fuel.
Thanks Mechanicboy !
updated on my engine
Today, I made bronze bush for front house bearing
AND, it ran for 25-30 seconds, twice.
I unfix it agian, check it ... I noticed the shaft is not good and it does not fit perfectly with the front of housing, I will do the new shaft and try to fit best with the front house bearing,. I hope it will be okay
Thought that was the problem
Hi All !
Now it is very easy to run, but when i unplug connect battery it stops. I do not understand why ??
Your engine has very low idling RPM and glow plug filament probably cools down between ignitions.
Try four stroke glow plug.
Anyway amazing low idling on your two stroke baby - congratulation.
Yes it runs well.I must say that your engine is different than i expected.
Ordinary glow engine if it stops when battery is disconnected, it is caused by too rich fuel mix or low compression ratio...But in this method of carburation i dont know.
Small two stroke also needs plenty of oil for cooling and lubrication. Literarly say oil must spray from exhaust.
It’s two rich mixture on idle and it’s not two stroking, you need to lean it out so it runs faster. But not for to long with A fly wheel, it needs a propeller for cooling and much lighter will run faster. Propeller size 9 x 6 or 9x4.
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