I just talked with a friend that has a small engine sales and service. He says that Stihl is comming out with a 4cycle ignition engine that will be lubed lilke a 2 cycle ...something like a ys four stroke on gas with ignition. I think we are on the way to that dream machine-right Kevin M? Captinjohn over and out!!

I LOVE the idea, but I will be very suprized if the engine will ever be light enough for an aerobatic plane. Should be AWESOME for scale planes though. 'Course it will be quite a while before they hit our market.

Jeff

Honda came out with a 4 cycle weedeater back in the early to mid 90's and it was a big flop. I got out of the small engine business a couple years after that so maybe it made a comeback. I know I haven't seen one since those days but who knows...

If the EPA gets their way all 2 strokes will be history. I suspect though that any small 4 stroke will be internally lubed to avoid pollution implications.

Vince

EPA was the reason that Honda first developed a 4 stroker weed beater. They were the first to produce one and while it was cool as crap it ran like that too.

Be interesting to see if the oil in gas feature allows much lighter weight than the Ryobi and Honda sump types......keep us informed .......

I know this engine will not be ready to install in a RC plane. That is where we all come in. People with ideas on how to get it to work for our requirements can possibly convert its use RC for Planes. That may be different carb or ignition or whatever. Have patients, and a open mind. Look around at all the neat accomplishments made already. Thanks CaptinJohn

shindiawa has had the new technology engine available for a while now:

http://www.shindaiwa.com/c4tech/index.html

The Shindaiwa, is basically the same setup as the YS four strokers - but using reed valves -not a rotary valve.
The engine sucks in and stores -in a plenum, the intake charge - This happens on each stroke - tho the engine fires on every OTHER stroke.
So -- the plenum holds a charge, waiting for the intake valve to open--which is above atmospheric pressure --I have no idea how high this pressure is - but on the YS it can be as high as 6 PSI- I redesigned a YS to accept a tuned length plenum -a few years back - documented it - no one was interested - as it made the whole thing pretty large - anyway - this technology does work - just depends on how much time/ space/ money etc - is poured into it.

Only engine I ever saw that had a nylon cam......

good quality nylon--

That Nylon cam saves weight? Maybe cost also! Why do we not see more ceramics in cylinders or sleeves? Some small glow engines have them. Thanks Captinjohn

Off the path a bit but briggs/Stratton tried the nylon cam for a while but ripped the gear teeth out of them.

Nylon cams, sheet metal cams, bearingless engines are the result of some idiot trying to reduce cost. It sure seems like low cost wins out over proven technology and good quality way too often these days.

The Shindawa (YS gas motor) sure looks interesting. I would propose that someone make one as a boxer twin with a flathead design (valves in the block) to narrow the engine. With the crankcase supercharging, it needs a low compression ratio anyway - low compression works fine with a flathead design as it unshrouds the valves. Roller tappets on an induction hardened steel cam, cam riding in needle bearings.

A flathead -- with the intake in the block and the exhaust stacks out the top .
Waaay back when - some guy redid flathead Fords - using a reverse grind "Tucker " cam --which had the intake manifolds on the sides of the V8 and the exhaust stacks went out thru the ports originally used as the intake ports.
At least the exhaust did not heat the block.
I don't know how many of these were done but it was in the mid 1950's -
Much of the "new engin stuff goes back into the 1920's or earlier - About the only new design was the Wankle .
The ring a ding setup with the piston on the same plane as the crank and driving thru bevel gears is also an old -- but inefficient layout -
I ran a flathead Ford that really smoked (no pun)- and ran with the then new OHV Chev V8s- but truly efficient designs - have a way of rapidly moving to the front of the pack - that's why most of these other setups go by the wayside (as did my Ford)

Has anyone thought of making their own gas/ignition single cylinder four-stroke by utilizing one jug from the RCS 5-cylinder radial?

Looks like the Stihl is going to beat out the Shindiawa..... CaptinJohn added photo

This is the reply I got from Stihl after asking if I could just buy engines;

Hello Mr. Cluff,

We are in receipt of and thank you for your message. Our engines are
manufactured strictly for use in Stihl manufactured products. They are not
sold separate of a completed unit. Thank you for your interest.

Sincerely,
Paulette V. DuPree
Co-ordinator, Customer Services
Stihl Incorporated



Sounds like it's time to go to the dealer and tell him my weed trimmer is broken and could he please order me a new engine for it.

Birddog: I got the same reply....from Stihl Corp.

Guess they don't want to waste time on folks like us huh? I did stop by a local John Deere tractor rental shop near my house, they have a new line of chain/weedie engines from Italy, verrry lightweight and Ferrari looking, asked about just the cylinder, piston set and crankcase, they want $220 just for a few parts, the complete chainsaw was about $200. If possible check that engine out, looks like a good liteweight performance 2cycle engine.