Where can I find Information on how to modify my OS 40 and 46LA engines to get the most power? Are there porting procedures?

The LA series are really an economy engine and aren't suitable for high performance applications. I don't know of anyone that has done extensive modifications on them. Your best bet is to buy a FX series engine (or in the case of the .46 the AX). These are high performance engines with ball-bearing supported crankshafts and schnuerle (sp?) porting. You will get more performance per $ that way.

There was an article in Fly RC about timing an engine. Basically, it involves the percentage of nitro in the fuel, the heat range of the glo plug, prop and the cylinder head temp. This will require some experimenting to find the right combination for optimum performance/power from your engine.

The least expensive (and least frustrating) way is to get yourself a decent ball bearing engine. Thunder Tiger PRO, Evolution, OS and possibly the GMS engines will provide substantial power/performance gains with prices from around $65 - $115 for a 46 size engine.

The LA series (and other bushed bearing engines) are normally economy engines and do not lend themselves easily (or cheaply) to performance modifications.

Hi GarMan,

Yeah I think getting an OS 46AX or other cheaper bearing engines is
the way to go.. Just read up on them here and talk to people at your
club, Loads of information that will save you some $$$$ in the long
run that will get you the best bang for your buck..

That being said, I have a LA-46, which has ran great and still does.
I was trying to get alittle more power.. I checked the muffler on
mine and the tail pipe exit was slightly smaller on the chamber end
so I drilled it out to be the same size as the exit, "I did not enlarge
the tail pipe, just made the entire length the same size. I did the
same on the engine inlet to the muffler. I then removed the baffle,
which gave me a "slight" power increase.. But after the baffle
removal the engine would leave about 1/4 tank left in the tank, So
I reinstalled it.. I did "slightly" increase the baffle exit hole and I
drilled out a few extra holes around the tail pipe.. Now I did get a
gain, But it was ever so small.. But it was free with little work!!
If you do try this the main thing is to make small changes to
make sure you keep enough pressure to M.T. your tank!!

Does all that Davis Diesel hocus pocus work?

The advertisements seem unrealistic. Really, converting a .46 to a .60 or whatever it was?

I was hoping when I read the advertisement that I could get plain ole diesel at the gas pump but I read somewhere here that the engine needs RC diesel.

Hey, I'm not sure about the hocus pocus.. But Diesel's sure do
keep some of the bugs away.. At least it does at our field..

Yes RC diesel is different.... But you sure save on fuel cost..

What do you guys think of the Tower Hobbies 46 ABC with 1.75 BHP @ 16,000 rpm? It seems to have the most bang for the buck at $74.99.

Lordy where to start. Yes you can port an engine and improve its performance. Clarence Lee has been doing it forever. But you can go the other dierction in a heatbeat also. Best to not play with the ports too much. I have tinkered with one engine I have. It was a hunk of slag anyway. I did get a modest increase in power. Wasn't worth the hassle.

The davis Diesel mufflers do work. They are tuned mufflers. They act like a minature pipe. They in effect create a vacume at the exhaust port when the fresh fuel comes in. Sort of like a supercharger with no moving parts. Do a search here on "mousse can mufflers". You use an empty mousse can to make your own coustom tuned muffler. Some fabricating is required. But they really do work.

Lastly you could try more nitro and a colder plug. You would get more power this way.

The best solution however is a new engine. An Irvine, OS FX/AX, Enya ect. I hear the tower engine is strong. And a good price as well. I do know that An MVVS with a tuned muffler is an animal. I have a 40 and it just plain honks. The newer 49 should reall pull whatever you want around with authority. And on 5 or 10% nitro to boot. Good luck whichever way you go.

Mark Shuman

Raise the exhaust port so that the opening timing is over 160 degrees.

Open up the carb.

Open up the intake port on the crankshaft as well.

You can get a lot of power but usually at the expense of all of the low end performance, you may not even be able to taxi the plane.

Have fun

Gar - The best trick mod for any OS LA engine is to sell it and get a better engine to start with. The LS are great engines for beginners becaue they are darn near idiot proof and they are cheap, but monster power they don't produce. I suppose you could grind ports to gain some power, but it probably isn't worth the effort.

As for calculating HP@RPM vs $ to find the best engine... don't bother. The HP numbers are meaningless the way the manufactures test the engines. Don't feel bad, we all did the HP/RPM/Price thing when we first started, but believe me, it means nothing. My suggestion for a user friendly small glow with more umph than the LAs would be to get one of the hot BB OS engines and feed it 15%-20% fuel. If you want a hotter plant at the expense of a slighly more difficult setup, look at a YS45 with tuned pipe and feed it 30%. I ran that combo a few years ago.... smokin! Not as much power as an all out racing engine, but it was impressive for a 45. Don't bother looking for HP/RPM ratings on the YS... they don't even bother to publish them, but it will out turn a OSFX/AX anyday.

If you really, really, believe that you will need all the horsepower potential that you can get from a small glow engine, go out and spend a whole bunch of money on a Dubb Jett racing 40 with a tuned pipe. Expect to blow a glow plug every other run or so, and they will be special glow plugs that will be rather pricey. Also expect to be tuning the pipe all the time in the never ending search for the "perfect length" for maximum. You can also plan to be spending a lot of time figuring out how much to shim the head for the fuel you intend to run. You might also have to mix your own to get it "just right".

While you are doing all this, your friends will be out having fun flying with their stock engines and thinking you're nuts.

The other option is to go purchase a good .60 size engine to get more power. Cheaper, faster, and easier.

The Tower engines are a good value and do put out excellent power for the price. Only down side of you can call it that is that some of the engines have an air leak somewhere. This means that the engine can't be shut down even with the carb barrel completly closed. This problem isn't on all the Tower engines, just on some that are produced. The carb barrel also turns rough on some Tower engines. I bought a TH 75 which was rough turning. There was a bit of extra material on one part of the barrel housing which I polished out with a Dremel and now it turns as smooth as my FX engines. I love my FX engines but they are pricy. Thats why I went to TH for the 75 engine

Is this the same leaking problem that I've been reading about on the GMS engines? By the way, who manufactures the Tower Hobbies engines? It's not GMS is it?

The Thunder Tiger 46 Pro is nearly as powerful as the OS 46 AX at a much lower price. A good value for the money.

And listen to JownW about HP ratings. The manufacturers all try to outdo each other in HP, and do their evaluations with props that are much too small to be practical. (They'd fry the engine in a few runs.) These evaluations are also done way above the maximum torque ratings, which is what would actually be useful to know. Unfortunately, very few (if any?) manufacturers list torque in their advertising. []
Dennis-

Torque is good, I think I'm a 4 stroke convert now.


Andy