Another version of how not to build a model engine

Gallery, Projects and General > Project Logs

<< < (33/41) > >>

sorveltaja:
I've tested sparking plugs with those ceramic rings, and they definitely don't wear out as easily as ptfe.

On the other hand, as this engine is on the experimental state, even the spark plugs need to be easily disassembled and cleaned, if needed.

Using ceramics doesn't make that easier. Not to mention, that it's quite delicious delicate job to make parts from it, that fit.
Plaster anyone?

Big white is the resistor body, that was originally attached to an automotive ignition coil, that I use. Next is one of the spark plugs.
And the marble looking thing is just one of the rings, that I managed to hack out of that big white. Bluish colour comes from felt tip, that I used to mark, where the cut was made.

Conclusion at this point is, that the engine still runs at too rich fuel mixture, causing contamination on the sparking plug rather easily.

--------------------------------
Mad jack, somehow that cyl.bore/4 = carb bore makes sense, as it says, that I'd need to enlarge current carbs throat from 1.9mm(~0.075") to 2.6mm(~0.102").

Anyways, the engine already runs too fast with that 1.9mm carb bore, if allowed.

sorveltaja:
Today I disassembled the engine, and whole combustion chamber was again coated with bituminous black dirt :wack:.

It is now cleaned, and before going back to ordinary carburetor, I'm going to make the vapor carb, to test if it gives cleaner combustion :coffee:.

NickG:
S,

Somebody over on HMEM just finished an i.c. engine and used the vapour carb with really good results. He also tried the same tank / carb on his hit & miss engine and that ran really good too, so much so that he is making another jan ridders vapour carb for that too!

http://www.homemodelenginemachinist.com/index.php?topic=6352.105

Nick

sorveltaja:
Nick, thanks for the link :thumbup:.

I occasionally visit HMEM, but somehow I've missed that excellent thread.

sorveltaja:
I have started testing with vapor carb, and also discovered the blowback -phenomena.

Not a new thing, as the very first running test were made with same kind of carb.

Back then I tried the ball valve to prevent blowbacks, but couldn't get it to work.

But this time I'll be using adjustable spring loaded valve:

Valve needs to be lapped, and spring added. Also the bigger brass part needs some brass tube, as the whole thing is to be installed between the engine and fuel tank.

Navigation

 Message Index

Go to full version