My first gasoline engine

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Joined
Feb 3, 2021
Messages
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Location
Schifferstadt, Germany
Hallo Kollegen,

Ich bin neu im Forum und habe bereits mit leuchtenden Augen gesehen, welche schönen Motoren hier sein werden. Bisher habe ich immer Heißluftmotoren und auch etwas mit Dampf erhalten. Jetzt habe ich vom Bau eines Benzinmotors gehört. Da ich keine Ahnung von Benzinmotoren habe, habe ich Einfluss auf den Motor, den Jürgen Heinen wahrgenommen hat. J. Heinen entwarf den "HEMO-Tracker" als Einstiegsmodell. Ich habe allerdings ein paar Modifikationen gehört. Die ersten Teile sind fertig, aber es ist noch ein langer Weg, bis der Motor fertig ist.

Hier einige Bilder vom zentralen Stand:

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Hallo, ich hab mehrere Trucker gebaut. Einer hat sogar ein Modellflugzeug angetrieben.
Du hast eine sehr schöne Ausführung gebaut.
Gruß Rudi
 
Ich habe mit Stirling angefangen und bin zur Verbrennung übergegangen und war von Anfang an ein glücklicher Motorenbauer. Viel Glück bei Ihren Fortschritten!
 
Hallo Rudi,

das interessiert mich natürlich. Gab es Ihrer Meinung nach bestimmte HEMO Tracker-spezifische Probleme, die mir bekannt sein sollten? Ich möchte, dass mein Tracker mit einer Glühkerze und einer Zündkerze läuft. Das Zündsystem verwendet die Leiterplatte eines Lichtbogenfeuerzeugs. Kann für ein paar Euro gekauft werden. Deshalb habe ich bereits eine Nockenscheibe und einen Mikroschalter für ein elektrisches Zündsystem bereitgestellt. Ich bin erstaunt, dass dieses "Schwergewicht" sogar für Flugzeuge geeignet ist. Es könnte auch viel einfacher gemacht werden.

Hallo Longboy,

Ich habe auch Heißluftmotoren und ein bisschen etwas mit Dampf für viele Jahre gebaut. Je kleiner desto besser. Jetzt möchte ich auch einen Benzinmotor bauen. Ich bin gespannt, ob ich das kann, denn ich habe nur schlechte Werkzeuge von Rotwerk.

Grüße, Günter
 
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Hello and a happy new year everyone.

After a long time I was able to continue building my first internal combustion engine. He's ready to walk for the first time. Unfortunately, it doesn't show the slightest sign of ignition. Because I have no experience with internal combustion engines, I don't know what it could be. So I have to rely on the help of experienced combustion farmers.
I'll describe the current condition of the engine, maybe someone of you can help me further:
The basic structure of the engine is largely built according to the "HEMO" Tracker "plan by Jürgen Heinen. The carburetor is also built by himself, based on drawings from the Nemet Lynx - 15cc SOHC engine.
Piston diameter 25mm, compression 8: 1. The compression is good in my opinion, because it offers great resistance in the dead center. The valves are ground in with various lapping powders. Opening of the valves: 2mm, valve clearance 0.15mm. Ignition: glow plug, fuel: Aspen 2.
Controls: inlet opens 10 ° before TDC, outlet closes 10 ° after TDC. Overlap therefore 20 °. The valves remain open for 200 ° each time.
I don't trust the carburetor. When I blow about 1 bar of air into the intake funnel on the removed carburettor, a fine spray mist comes out of the outlet when the throttle is half open. This can be made clearly visible with a white sheet of paper held in front of the outlet. But if I install the carburetor and the motor with the cordless screwdriver for about 10 seconds. turn, the combustion chamber remains dry. I'm afraid nothing is gassed there.

Do any of you have any good advice on how to test that the engine is igniting and building up pressure? Can someone sell me a used, working carburetor for this 10cc engine?

Greetings Günter
 

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Decrease your valve overlap. Compression at 8:1 seems too high. I pressurize my cylinders with a rubber tipped blow off nozzle to the spark plug hole off the air compressor at very low PSI and turn engine over for compression pressure and intake vacuum draw if the valve timing is near correct listening for the valve closures to the proper crank positions.
I'm finding on my home made carbs that the correct way to test carb draw on the fuel is to supply a vacuum at either end, air horn or manifold side, instead of blowing air thru either end of carb. Use you carb like a straw with a clear tube on the feed valve in a cup of water and suck. Then try to blow thru and see if it picks up water thru the feeder tube. Only works on my carbs by vacuum. Just a mystery of the Venturi principle via the carb bore diameter differential I guess. Used .10-.15 carbs available on Ebay all the time.
 
What have you set the ignition timing to?

If fuel is present on the spark plug then fuel is getting through. You will have to play with the mixture and ignition timing.

Also look for air leaks between the intake and carburettor. A quick test is timing put some oil on the joint. If the motor runs you have anair leak.

Cheers,

Andrew in Melbourne
 
What have you set the ignition timing to?

If fuel is present on the spark plug then fuel is getting through. You will have to play with the mixture and ignition timing.

Also look for air leaks between the intake and carburettor. A quick test is timing put some oil on the joint. If the motor runs you have anair leak.

Cheers,

Andrew in Melbourne
Andrew, he states it is glow plug ignition. Doesn’t say though how he is driving the glow plugs re batteries etc, also the fuel Aspen2 is petrol(gasoline) not methanol so maybe something is lost in translation ?
 
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Thank you colleagues for your support.

Hello longboy,
the translation of google is unfortunately very bad. I still have to have the text translated, then I'll answer.

Hello Andrew,
I put a glow plug in. To start, I have a tool for clamping and an integrated battery. So there is no defined ignition point. I will check the tightness of the carburetor to the engine again.

Hello gadabout,
Aspen2 was recommended to me by a colleague here in Germany. He says he runs all of his glow starters on Aspen2. Would you recommend another fuel?
 
Yes , you need a model engine fuel specifically for glow engines , one that is methanol based with oil added, there are particular ones for model four stroke engines as well . Try a local hobby shop. It will not start using a petrol/gasoline based fuel.
 
If you have a glow plug type ignition, as others have said, you need to run methanol fuel typical of radio control (RC) models. Fuel is typically sold at RC hobby shops. You may have fouled the wire heating (glow) element of the plug if running gasoline so may not function properly. Maybe best to have a new plug handy. Fuel tank height (hydrostatic head) is important for the carb to draw fuel properly. Suitable ignition voltage & current capability is important for the glow plug to ignite fuel. You can get battery based glow ignitors that fit the plug, or just the plug/harness & connect to your own power.

Here is some information on timing (glow/methanol)
Cam Timing Methanol Glow Engines

Here is some information (post#6) regarding (glow/methanol) carburetor sizing sizing
Looking for inexpensive carb for trial running of Seal Major 30cc
To experiment & get it running, maybe you can get an RC carb & at least isolate the issue of your carb.
I was going to suggest Conley (Perry carb) because he has a wide range of sizes, reasonably priced etc.. But for some reason the web link is not functioning. Anybody know if he is still operating? I just bought some carbs a few months ago.
http://www.perrypumps.com
Alternating you can probably find a used carburetor, as long as its in good condition & appropriate throat diameter.

If you want to see timing, compression ratio or other data on commercial RC glow engines, this is a good resource
http://sceptreflight.com/
 

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Hello fellow colleagues,

a colleague sends me a suitable carburetor and a hot glow plug. As an alternative to Aspen 2, I now also have methanol fuel. I also use a glow plug starter with plug and battery.
I will now follow your advice as far as possible. I will tell you about the results.

Greetings Günter
 
Hello Günther
I am living very close to your home. And we know each other from the Sinsheim Exhibition. If you want i can help making your engine run. And we can talk German, this might help. Btw, beautiful little engine.
Greetings Stefan
 
Hallo Günther
Du hast Post bei Yahoo.
Gruß erstmal Stefan
 

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