Longboy's "SIDE SHAFTER" Model Gas Engine.

[dozerdroid]

Thank you for sharing, super cool.

 

[minh-thanh]

Congratulations !
I like the way you do the engine, make a the engine the way you want it
Thanks for sharing.

 

[awake]

Longboy, I am speechless. What a concept, and what a wonderful result! Well done!!

 

[Longboy]

Thanks awake! The geared crank concept worked so well with my SUPER TEE triple that it was worth a look/see on another project for this year with SIDE SHAFTER. I may come back to it with a different multi- cylinder layout in the future and maybe other modelers will try it. Sure gives some interesting attentions and visuals to open crankshaft engines.

 

[awake]

Aha! Now I will search for the SUPER TEE triple to see what you did there!

 

[awake]

Longboy, after reading the SUPER TEE build, and this one, my mind is buzzing with possibilities ...

 

[Longboy]

Looking at HMEM user "awake" and his Webster build. He made a carb from plans posted, developed by Chuck Fellows. I'm looking at them and started a quick project after hey/ nay the self made idea for a long time. I don't need the throttling valving as through the lean/ rich fuel feed........ will vary the RPM in a narrow but satisfactory range.

The SIDE SHAFTER now has the 4 inch steel flywheel. Slowed the engine down some. Trying this mixer on this engine as it is four cylinders and with the throttle open very slightly on the O.S carb here, the engine maxes out it's low RPM smooth threshold in the 1000RPM range. Conclusions and results of the home grown mixer to come.......

 

[Brian Rupnow]

Lovely bit of work Longboy. Engine runs very well and shows a lot of dedication. A piece of engineering artwork!!---Brian

 

[Longboy]

Lovely bit of work Longboy.................

Thanks Brian. Picked up a few ideas and methods over time here......some from your pages of know how!

 

[doc1955]

That is an interesting engine runs great. Very nice thanks for sharing!!

 

[Longboy]

The fuel mixer works well. Swapped it between a twin and SIDE SHAFTER and got the same response.

I made a duplicate right away and tried out on another couple of twins. The venturi is 5/32in. bore. The brass air jet for this engine is drilled 1/8 in. currently. With the needle near closed it will start and idle around 1100 and through enrichment settles back to 700 and stalls. This 400 rpm move is all over in a quarter turn of the needle screw with the eighth incher.

Along with a couple fixed bore air jets I made a variable jet. 10-32 set screw restrictor under a 3/16 hole. I'll take the fixed bore as you only need the fuel screw to vary the engine speed and each engine has its own carb anyway. Let's see what it looks like running with the 5/32 inch air jet.

 

[awake]

If I'm seeing right, it looks like you have only the needle adjustment, but no throttle - ?

 

[Longboy]

If I'm seeing right, it looks like you have only the needle adjustment, but no throttle - ?

Yes. Fixed air jets and variable fuel.....no throttle.

 

[Longboy]

Using model airplane carbs in the .15 size for most of my gas engines. They work fine in engines beyond their purposed thimble size displacement @ 15K RPM. Adaptable for my purpose, the settings more than what I need. You play with the air throttle and fuel mix screws as well as set the position of the needle valve in the fuel jet.......can drive you nutz on a fresh engine you are trying to trouble shoot. Looking at most hit/miss engines with one valve fuel supply mixers, sees to the needs of my steady idle, stationary industrial type models .

Some assumptions I made looking at the O.S. carb is the intake horn diameter. At about 5/16 inch and duplicated on my mixer. Fuel did not travel up the line too well. Too large an air horn opening with no throttle provision......no vacuum. Reduced to near the venturi bore as an air jet insert into the intake horn..........results turning very favorable. Seems that the air demand on models with intake port diameters close to the venturi bore can also be the intake horn diameter bore on a twin and quad cylinder engine running at similar idle speeds, 1000-1200rpm in my evaluation of a couple of engines double the displacement from another. Also apparent that the venturi effect takes place beyond the carb body, at the air jet insert. Got a whole world of ambient atmospheric pressure starting there and your intake manifold plenum takes care of the other end of the process.

This basic fuel mixer is easy to make. Single needle/seat fuel control. Fixed air jet insert into air horn control. Adapter to fit mixer to manifold.