RE: Who is converting Toro trimmers?
 

Hi Scott, Just looking through the thread today and wondered if you have ever thought of trying the 2 bbl piston in a 1 bbl engine. I haven't compared them side by side lately myself, for compatibility, I am just thinking about the dome on the 2 bbl piston and whether it is enough of a dome to raise the compression in a 1 bbl cylinder? Think there could be anything worthwhile to this?

RE: Who is converting Toro trimmers?
 

I think Dave tried that. There is very little clearence so I think it hit the top of the cyl.

I see Ryobi has a 25.4cc blower out now, and a trimmer. It is the Toro engine. I got one. But it is a 1bbl version with only 1 ring.

RE: Who is converting Toro trimmers?
 

Hi Scott,
Another idea I know you and a few others must have thought of, and that is sinking the spark plug further down into the cylinders on engines. It should be easy to do for gasketed spark plugs and it looks as though the bottom thread of the spark plug hole never gets used on some of the engines I see. Of course clearence for the plug needs to be checked. I don't know if this will raise the compression very much, or help at all?, but has anyone tried this?
(I would be very surprised to come up with an idea that someone has not tried!)
John

RE: Who is converting Toro trimmers?
 

John,

Never thought of doing that. It may help.

Has anyone put one on EI yet. I did a couple so far. It makes these little engines very light. 2lbs 12oz W/O the EI unit. So even with it they are under 3lbs. Power was the same for me. The timing had to be set at 30+ deg. The stock mag is over 30deg at max advance. I tried at 28-30 and it did not idle well. At 33 or so it was awsome. The EI I used was Roy Sholl auto advance ignition.

RE: Who is converting Toro trimmers?
 

Scott what other Spark plug other than CMR7A can be used on yr engine?

RE: Who is converting Toro trimmers?
 

I do not think Champion makes a plug the same. I looked online and they didn't show one. I can get the plugs for $4 each and send you some if you would like.

RE: Who is converting Toro trimmers?
 

Hi Scott,
The light EI engine is interesting, even though we did have a discussion a few pages back in the thread about the negatives on doing this. A light engine as we all know will allow more airplanes to be used. What did you replace the flywheel with. We know there had to be something to provide a mounting for the prop hub and you probably needed a magnetic pickup or ? for the ignition adjustments etc., but my other question is, how smooth do these engines run without the flywheel? If the engine can still run smooth enough, my concerns about short crankshaft life might not be a concern at all. When you think of it, few of our engines will ever run for hundreds and hundreds or ? number of hours as a full scale aircraft engine does.
John

RE: Who is converting Toro trimmers?
 

And let us think about it this way: Those engines are designed for years of use with a clogged filter, improper lubrication, and poor cooling. The most important thing to me, what holds us back the most, is that they are designed to run on low octane gas with grass clogged cooling fins, high heat and a dirty plug. That LOW compression ratio that allows all that is what holds us back, in the 4 strokes most of all. We run ours with clear fins, lots of airflow, and can use high octane with a perfect mix of oil. If only there were a readily available source of higher CR pistons we would be able to fly allot more models on the same engines. I would love to fly my TopFlite giant mustang on a Honda GX50 4 stroke.

RE: Who is converting Toro trimmers?
 

Hi Subarubrat,
From what I have read over the years concerning Briggs and Stratton and other even smaller bore engines, regular grade gasoline has quite a bit more octane than any of these engines need. The volume of these small cylinders is minuscule compared to auto engines and the heat generated inside is a lot less also, and the heat is basically what determines the needed octane. We can raise the compression a bit, by machining a small amount off of the bottom of the cylinder and maybe by sinking the spark plug some also. Of course, the spark plug clearence needs to be checked. It doesn't take much with some engines to have the piston hit the top of the cylinder and by machining the bottom of the cylinder we are messing with the geometry of the crank and connecting rod, but it is usually not a big problem because we usually can't really machine much off the bottom of the cylinder. I recently have thought about sinking the spark plug also. I have heard of guys using Premium gas in these small engines and have wondered if anyone can prove the need. If you want to check out what seems to really be hot engines in the 40 to 50cc range, that are designed to scream, have you ever looked at the engines used on the mini pocket motor bikes? I have seen these engines on the net and they are pretty cheap. I was tempted to buy one, but I have yet to fly a gas engine. I fly glo engines and haven't decided on what to build for a gasser. I won't go over 1/4 scale in size so I probably won't need one of the "screamers" myself. Lets see if we can get some more comments on this.
John

RE: Who is converting Toro trimmers?
 

John,

The Toro ran great and had little to no vibration. Better on EI than with the flywheel. The prop hubs are different than the mag hub. It has the taper machined into it to center it up like the flywheel. It is actually stronger on EI than with mag because the taper is holding the hub and not just the threaded part of the crank. That is the weakest part.

RE: Who is converting Toro trimmers?
 

Hi Scott what is the price of your toro 25cc EI engine setup ready to fly.

RE: Who is converting Toro trimmers?
 

With CH ignition it runs $265 shiped. If you want any more info please email me directly.

RE: Who is converting Toro trimmers?
 

thanks I will :D

RE: Who is converting Toro trimmers?
 

Very interesting thread! I wonder how a Morris Hobbies Jerry’s Big Boy would fly with a Brillelli 25cc GT? How is the throttle response of this motor? Hey ramduster what do you think about a JBB with this engine? Would it be 3D worthy? Poco do you run all of the engines you sell?

RE: Who is converting Toro trimmers?
 

I have a thunder tiger 1.20 2 stroke on my Jerry's big boy and it is way more power than any body in their right mind needs:D. the JJB is a very light plane for its size. the 25 GT that I got from Scott last week is going on the red kangke monocoupe 90A. the engine is a very nice piece of work if it runs as good as it looks I will be in great shape.

RE: Who is converting Toro trimmers?
 

So by admission you are out of your mind ;)

I have not paid much attention to gas engines – I know that it is a 25cc engine what size glow engine would this engine replace?

RE: Who is converting Toro trimmers?
 

Yes I am or at lest that is what they say :D. the engine would replace a 1.20-1.60 2 stroke but be more heavy and a lot less money on fuel and no clean up after flying.

RE: Who is converting Toro trimmers?
 

To RCBOZO,

We do run every engine before it goes out. I figure it helps reduce the chance of a problem for the buyer, and makes me feel better about sending it. I would worry too much if I didn't hear them run first :)

Scott

RE: Who is converting Toro trimmers?
 

I know that the info I am lookiong for is somewhere on this thread but I can't for the life of me find it. Does anyone know what the taper on the shaft for this Toro is. I want to make a prop shaft for a friend who is converting this engine to CH Ignition and I need to machine a hub. I want to bore the hub to fit the exposed shaft when I remove the flywheel.

RE: Who is converting Toro trimmers?
 

I will find out for you. My buddy Mark does the lathe work on our engines so I will ask him.

RE: Who is converting Toro trimmers?
 

When Mark put the measurments in on a CAD program he came up with a 9 deg taper. If you get close it will still center up and run true. Also we usually run a set screw in the hub into the threads to keep it from moving. That is if you plane to run the EI on the front of the engine.

RE: Who is converting Toro trimmers?
 

Scott,
I have a tip for you about using setscrews on to a threaded shaft area. To use a setscrew without marking the threads, drop a piece of solder into the hole first. About as big a piece as you can get across the diameter of the hole. This holds very well, and doesn't damage the threads on the shaft. It is something that is done with reloading dies for ammunition. I have more than one hobby and sometimes you can transfer ideas. Try this and I think you will be surprised. If you need to take an engine apart later, you won't have to deal with rough spots on the threads. You tap the assembly, after removing the setscrew, to get it loose.


There is a thin line between a hobby and mental illness -- Dave Barry.

RE: Who is converting Toro trimmers?
 

That is a very good idea. Thanks, I will do that.

Scott

RE: Who is converting Toro trimmers?
 

poco242: Are you going to build a Toro 25 with the new lightweight flywheel that" bn120" is now making and selling? That may be a killer combo. Thanks Capt,n[8D]

RE: Who is converting Toro trimmers?
 

Capt,

I have heard about them, but the price is about $75 isn't it? For that it is better to loose all the weight of the fly and mag and go with EI. I guess if someone wanted to go with mag and loose some weight it would be fine. But it is only like 4 oz so for the money is it worth it? Not to me, but it may be to someone. It is a good idea. Does he actually make them for the Toro?

Scott