DIY Two-Stroke Engine

"durabol" wrote

Has anyone made a 2-stroke engine from scratch? One may need to cast
aluminium, may need a lathe and milling machine with boring head and
hone or perhaps the boring and honing of the cylinder and bearing
journals could be farmed out. A commercial carburetor and piston could
be used. Two-stroke engines seem simple enough that home construction
may be possible, if not practical.

A direct drive engine will be that much heavier when you take into
account the weight of the drive reduction system.

I am assuming you meant to write "will _(not)_ be that much heavier",
right?

If so, when is the last time you saw a direct drive 2 stroke aircraft
engine? Not me. Closest I can think of is a model airplane engine, and
that is only practical because of the small prop sizes. If you put a large
enough prop on a 2 stroke to soak up 50 hp, you will have to keep rpm's way
down to keep from having a real noisy, inefficient prop. You keep the RPM's
that low, and you now have a real inefficient 2 stroke engine. That is why
all 2 stroke engines have gearboxes or belt drives to reduce prop speed.

You might do well to consider a 2 stroke supercharged diesel engine. You
make one of those, and make it scaleable by adding more banks of cylinders,
and the flying world will beat a path to your doorstep.
--
Jim in NC

Suzuki built a 650cc water cooled 2 stroke twin for Arctic Cat. I think
that engine is about the ultimate in big bore 2 stroke twins... At one
time I considered getting 2 of these and putting them in a small sports
car like a Triumph Spitfire but I've since moved to a state that does
emissions testing and that won't pass here...

Suzuki just about ruled the 2 stroke motorcycle market with their rock
solid reliable engines. You could count on a 75k miles out of a Suzuki
triple when the other companies' bikes would only go 15 to 20k miles on
a set of pistons...

There were also some big bore 2 stroke dirt bikes. I know all the major
players in the market built them but the one that comes to mind was a
500cc Husqvarna single. Sleeves, pistons ect are all available for
these bikes could be used to build your own. The easiest way to go is
to use someone else's engineering and machine work to build your engine.
That way the major parts to make would be the cases, barrels and
cylinder heads since the bike ones won't have adequate cooling. I
imagine that a 1000cc 2 stroke opposed twin would be pretty cool and
could be tuned to run at an RPM low enough for direct drive. However
it's not a good idea to put a prop on a built up crankshaft like all 2
strokes use and a belt drive or some such would be required.

I would highly recommend reading the 2 stroke tuners handbook if you can
find a copy. I have a PDF version but it's too big to eMail. Also talk
to Charlie at Superior Sleeve in Millwaukie, OR. Charlie has built more
custom 2 stroke engines than just about anybody alive today... If you
can catch him when he has time to talk, he will enlighten you a great
deal. It's been more than 20 years since I was building high
performance 2 stroke engines and I've forgotten a lot over the years...

Good luck and keep us posted if you go on with this project.

Tony

Morgans schreef:

You might do well to consider a 2 stroke supercharged diesel engine. You
make one of those, and make it scaleable by adding more banks of cylinders,
and the flying world will beat a path to your doorstep.

Hm. The flying world did not exactly beat any kind of path to the
doorstep of www.dair.co.uk, though they did exactly that. Wilksh company
wasn't far off, either, with equal lack of big success.

"jan olieslagers" wrote in message
...
Morgans schreef:

You might do well to consider a 2 stroke supercharged diesel engine. You
make one of those, and make it scaleable by adding more banks of
cylinders,
and the flying world will beat a path to your doorstep.

Hm. The flying world did not exactly beat any kind of path to the doorstep
of www.dair.co.uk, though they did exactly that. Wilksh company wasn't far
off, either, with equal lack of big success.

I suspect the two cylinders with 4 pistons is a bit unconventional, and will
have to work all the harder to prove itself.

I think the web page is about 10 years old, since much activity has taken
place. It looks like it is a bit heavy when you add all it needs to run in
an airplane, too. How about price? No mention of that, on the current
pages.
--
Jim in NC

"Morgans" wrote in message
...

I suspect the two cylinders with 4 pistons is a bit unconventional, and will
have to work all the harder to prove itself.

2 pistons per cylinder is not unconventional in the stationary diesel world.

Vaughn

On Mar 6, 2:44 pm, "Morgans" wrote:

If so, when is the last time you saw a direct drive 2 stroke aircraft
engine? Not me.

McCullough made two-stroke opposed four-bangers for miltary target
drones in several different sizes. Many of those were sold surplus and
found their way into several homebuilts and a lot of Bensen
Gyrocopters. I once owned one; the vibration was awesome, as was the
fuel consumption.

http://www.combatairmuseum.org/engin...ch0-100-1.html
http://media.photobucket.com/image/M...ctoshow026.jpg

And here's a video of one powering a Hummel Bird:

http://www.youtube.com/watch?v=ITB_dxbCTUk

Dan