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Congratulations, that sounds just like it should and clearly this thing wants to run, start was so easy 
Opposed Twin I.C.
- Thread starter Brian Rupnow
- Start date
Help Support Home Model Engine Machinist Forum:
Thank you George and James. Someone has asked that I post a few still shots of the finished engines, so here it is.---Brian.
RonGinger
Well-Known Member
Nice job Brian. Let me be the first to ask, So what do you do next? I can not imagine not having a near daily read of your latest adventures. How about something more scale, like an old VW 4 cylinder?
Thanks Ron--I have the notion that having successfully built singles, twins, flatheads, and overhead valve engines that my next build is going to be a two stroke. I have seen Jan Ridders 2-stroke plans, and they don't really appeal to me that much. I have seen a number of people on the forums who have built them but are unable to make them run without modifying them in some way, or else never get them to run at all. I need to find a proven design for a 2 stroke that doesn't exceed my current machining abilities.---Brian
Here is a nifty little trick for "old school" engine builders like myself, who still use a 12 volt battery to power the ignition on their engines. Rather than have a big ball of wire wound up with the engine when it is not in use, or two separate leads with alligator clips, I purchased a microphone connector plug at Sayall Electronics. Half of it mounts into a bracket on the engine, and half of it can be attached to the wire leads which run to the battery. The connections are solder type and can be easily connected with a small soldering gun. The lowest number of connector pins available are three, but that's not a big problem---Just use two, one for the hot wire and one for ground. The two plugs only fit together in one orientation so there is no danger of plugging it in wrong.
Cogsy
Well-Known Member
Runs like a dream Brian. Definitely would like to build my own one day.
I have just went in and reloaded the final Youtube video, using a different format to get a crisper, cleaner video with no fuzziness. It is much clearer now.---Brian
Got my laser tach out this morning and took a few readings. The lowest idle rpm without "faltering" seems to be about 1175 rpm. this surprises me a bit because it SOUNDS slower than that. The highest rpm seems to top out at about 4000 rpm, but remember, I am running with almost zero advance on my ignition timing, and it is fixed. My timing doesn't advance as the throttle is advanced.
I went up to Princess Auto this morning and bought a package of 10 "supermagnets" for $6.00 ---These things are incredibly strong in their attraction to any ferrous metal and to each other. I used a .344" diameter endmill to put two shallow pockets into the top of the angles which make up the framework of the engine, and two pockets into the underside of the polished brass top plate, then used J.B. Weld to anchor the magnets in place. I certainly hope I have the magnets in the correct way so they attract and not repel!!! This should take any rattling and clattering away when the lid is setting in place on the engine. I might need three men and a bulldog to get it off to oil the engine with my squirt-can.--- J.B. Weld takes a terribly long time to "set up", at least 24 hours, so I won't know until then if I have the magnets in the right way or not.
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canadianhorsepower
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You will need a Bull Dog to pull it up Rof}Rof}
to make your life easier slide it to one side then pull Magnet don't have any shear power
Good thought Luc---But, as you can see in the picture, the lid sets down into the top of the engine and can't be slid to one side. However, if I need a bulldog I'll give my ex wife a call----
I sneaked downstairs this morning and filed/sanded the excess j.b. weld away and tried the brass top plate for fit. It snaps into place very solidly--and is easy enough to remove that I won't need the bulldog!!!.---Brian
This is it!!! The polished brass top plate with the embedded magnets fits snugly in place, doesn't rattle when the engine is running, and yes, I can lift it up to remove it with my fingers. This will be my last post about this engine unless I am answering a question in response to someone. It's been a fun ride!!!---Brian
I have been asked on one of the forums I post on about the temperature of the engine, and how effective the fan blades on the outside of the flywheel are at cooling the engine. I had a devil of a time hunting down my remote sensing laser pyrometer, but I found it hidden in the bottom of a drawer. (It's not something you use all that often.) The engine will run exactly 10 minutes at a fast idle on one tank of naptha (Coleman fuel). Temperatures were taken during the last minute of the run. The cylinders run at 150 to 170 degrees F. The base of the exhaust stacks measure at about 185 degrees F. The ambient air temperature in the room is about 65 F---(I had my office door open to keep from gassing myself.) I would say that the cooling vanes on the flywheel are very effective with readings like that.I checked my tachometer against the readout on my lathe, and the tachometer agrees within 3 rpm of the readout on the lathe, so I guess that pretty well confirms that the lowest idle speed of the engine is around 1200 rpm, although it certainly sounds slower than that.
Longboy
Well-Known Member
Beautiful easy runner!Thm: Enjoyed the video. What kind of "mileage" or run time does your fuel tank provide for your twin? ------Dave
It runs 10 to 12 minutes on the amount of fuel in the tank.
