Lil Brother Hit & Miss from Minicastings

[gbritnell]

Hi Bill,
I have the 'Little Brother' that I built from Paul Briesh's castings many years ago. I also have a smaller copy of it that I called the 'Little Brother's brother'. A couple of things I did to mine which you might check out. When Paul built and sold the castings he never called for piston rings but I added them to mine. Next thing is the original cam design allowed way too much dwell on the points so I changed the profile and the last thing is the spark plug port is drilled and tapped at right angles to the combustion chamber port. Along with that it's deeper than a standard spark plug can reach and what happens is when you first start it and the plug starts to heat  up it will form condensation on the plug and foul. You then have to pull it out and dry it off. Once the plug is warm it's no problem. To get around that I made my own plug with a long reach to go all the way down to the combustion chamber port.
If you have any other question when you get to that point please don't hesitate to ask.
gbritnell
Here's the Little Brother's brother.
<a href="https://www.youtube.com/watch?v=9z-EBXX8jJQ" target="_blank">http://www.youtube.com/watch?v=9z-EBXX8jJQ</a>

[Jo]

... but stay tuned to this space as I doubt I will be able to keep my hands off the castings for long... must have caught that malady from Jo

Snap 







No quite snap mine is the air cooled version 

There is nothing more desirable than a set of model engine castings in spring: they are a promise of good times to come 

Jo

[Roger B]

Thanks Bill. 4 1/2" flywheels I think are outside my working envelope. Someday though...
Someone tell me I'm wrong. Can I do this on a mini-lathe?
 

In general yes, the limitation will be low speed torque which will depend on which generation of motor and drive board you have. I have turned a 5" (125mm) flywheel on a 65mm centre height Hobbymat.

[cheepo45]

Looks like a fun project!
I like the 4 1/2" flywheel size engines.
 They are not too heavy to move around, but they are big enough to be able to make most of the parts without a microscope!
I.C. engines are more of a challenge to get running right, but I love hearing the pop, pop, pop!
cheepo45

[b.lindsey]

George, thanks for the tips. I may well be asking more questions as the project progresses.

Jo, I should  have known you would have these castings lurking somewhere around the shop Only goes to prove my earlier point that I caught this from you!!  But yes new castings are good anytime and I still have several squirrled away as well, end even more plan sets filed away.

Scott, your Gade was under consideration but I like the look of the water cooled hopper engines too. The Gade is still on the list and I agree that this is a good size for lots of reasons.

Thanks to all for the interest, I try not to keep the build waiting too long. I'm not big on two projects at once, but this may just be too tempting 

Bill

[Jasonb]

I'll be following this one along too Bill, typically for me I have the bigger Hired Man castings which have a lot of similarities. May still be able to tempt you to do a Gade, I'm about to start writing up the 1/2 scale one I've been working on.

J