BME

Kioritz, is the parent company of Echo. Kioritz is an engine company in Japan that needed a vehicle to sell their engines so they formed Echo in the US located in Chicago. I have been to the factory in Chicago and it was a real cool place see. I was able to see new protoypes not in production yet and with my engineering friends help I would know when new engines were coming out before the distributors did. I even had the opportunity to test some before they went into production. I have a brand new back pack compressor with a twin cylinder engine they made that was never put into production. I was able to learn about their production line too. When a unit is being assembled and one bolt get stripped or cross threaded or a tiny flaw exists the whole unit goes into a big roll off type dumpster. I probably dont have to tell you what a engines converters dream that was to dig through that dumpster and get every engine I wanted for free!


Keith
BME

wvarn1957

My Feedback: (3)

Keith,

I really have no sure way of determining the age of these engines. As I said I got them in a Harris county surplus auction last year. One of the employees at the pruchasing warehouse said that the county maint dept usually replaces about every three years. That would put these in the 4+ year range.

The carb is a Walbro WT 74A E3. I have converted one of the engines and it runs pretty strong--- 20 X 8 MA wood semitar @ 6950.

Thanks,

Will

BME

Well I have converted the Echo 23.6cc engine with the longer stroke crankshaft. I did gain some power but I was hoping for more. The engine weighs 1lb 15 ounces and it turns the 16x8 APC at 9100 rpm on the first run up. It should get about 200 more with break-in. Funny but I find they dont want more than about 25-26 degrees timing. I am going to try a bigger carb and see if it gains more.



Keith
BME

Flypaper 2

Working on racing snowmobiles I find the higher the compression ratio, the faster the burn rate, therefore the less spark advance, because maximum pressure comes sooner. Also the smaller the bore the less spark advance because of the less distance the flame front needs to travel.

mikenlapaz

Keith,
What an informative site and list of products! Your instruct manual is now downloaded for reference. I used it for guideline on initial runs of a ryobi recently.

There is much cautioning made in articles and instructions on all carb adjustments not to get too lean and overheat the engine. April 2002 issue Model Airplane News has informative article COOL IT on Temperature Tuning, but it deals only with glow engines. I figure most of the principles apply to gassers as well. What head temperatures, at plug area, is considered safe operating temp for gassers.

'After Break-In Oils: prefernece is mineral oils, less plug fowling' . Is the addition of castor oil, even in small % a DO NOT USE thing for some reason? The M A News article mentions it for glow but how about with mineral or synthetic in gassers? (This is all new to me, just a student learning)

BTW, The BME site location is listed in Keith's profile. Impressive!

Magneto

Kieth,
What set up do you use to machine the piston top and base of the cylinder on the 23.6? Thanks, Dean

mlevings

My Feedback: (14)

I just picked up a busted echo GT160A trimmer. I can't find any info on it. Does anyone know what size it is. It is vary small, possibly 16cc? It should make a very lightweight small engine.
I finally found a local mower shop that is willing to work with me on getting some conversion material. I gave $5 for the trimmer and a Poulan 33cc chainsaw. Not too bad.

Mark

Flypaper 2

T'is a 16 cc

mlevings

My Feedback: (14)

What a day. I also found a Stihl dealer that gave me a great running FS80 (25.4cc) trimmer with a broken shaft, a great running Stihl 025 chainsaw that had been run over by a truck, and a large 60+cc cutoff saw that ate a ring to play with all for $20. The cutoff saw has a scratched up piston, but the cylinder looks good and there doesn't seem to be any other damage. The top ring is still good and the saw has great compression. I can't wait to fire it up and see how it does. I just have to remove all of the bits of broken ring from the crankcase.

BME

The subject of head temperature is very subjective. I personally do not like anything over 220 degrees. The cooler it runs the better. If you can get it to run at 180 or so it will live a very long life. What I see on overheated engines besides the obvious is that rings can loose the their spring tension. I have taken a few engines apart that had been run very hot and found that the ring could be pulled from the piston like a piece of copper wire. Anyone who has played with engines knows that a normal piston ring is easy to break usually with a piece flying across the room. I also find that if overheated the oil cooks in the ring grooves and eventually leads to stuck rings. If you have much discoloration or staining of the piston below the rings you have compression blow by. The we recommend a mineral based oil because its not as slick as some synthetics and it allows the rings to wear into shape of the cylinder. Modern super slick synthetics can cause a thing called ring skip or what appears to be a shiny glaze over the rings. These engines never fully break-in or develop full power.

Magneto:

I use a lathe to cut the piston. It takes several cuts to form radius on the crown of the piston. You are trying to match the radius of the combustion chamber. I also use the lathe to cut the cylinder base down. I have what we call a spud that slips inside the bore of the cylinder. Its just a round mandrel that is a couple of thousands smaller than the cylinder bore. We indicate the mandrel in the lathe to make sure it is running true then slip the cylinder over it and put pressure against it at the top of the cylinder with a live center. Then cut the base with a left hand cutter tool.


Keith
BME

BME

Ran the stroked 23.6cc Echo again today. I put the carb from a g-23 on it and gained some power. Its now turning a 16x8 APC at 9300. Vibration is starting to show up at this rpm. It needs more counterweight on the crank to spin this fast. I think I will go to the 17x8 APC to drop the rpm down and pick up some thrust. These figures are with a stock box style muffler.


Keith
BME

captinjohn

mlevings: You are one lucky dude. You must be in the right area. The small engine shops around here won,t give you the time of day. Lots of quick easy $$$ is what they seem to have on there mind. Capt,n

mlevings

My Feedback: (14)

Captinjohn, so far so good. One of the shop owners was an old r/c pilot. He flew back in the 70's. That made all the difference. He was a bit surprised to hear how big some of our aircraft engines are getting.

mlevings

My Feedback: (14)

Here is a shot of my echo 160 trimmer engine. I guess it is 16cc. I didn't like the stock ignition setup so I am converting it to electronic ignition. This thing is tiny. I still need to finish smoothing up the case and mount my magnet and sensor and it will be ready to test.

mlevings

My Feedback: (14)

Here is a shot of it next to a 25.4cc stihl trimmer. You can see how tiny it really is.

ZAGNUT

My Feedback: (1)

in the start of this thread i talked about removing the oil seals on the 21.2cc in order to reduce friction, well i ran the engine today and power is up by about 150 rpm, not much but every bit counts.

i now want to try some of keith's mods on this engine so i put the degree wheel on it to see where to start. here's the timing measured in duration:

exhaust- 132 deg.
intake- 116 deg.
transfer- 94 deg.

keith recomends:
exhaust- 164 deg.
intake- 144 deg.
transfer ???

in order to raise the compression to the max i need to lower the cylinder 1.5mm, no problem except that i'm going to lose a lot of that piddly 94 deg. on the transfer ports.
i'm thinking of cutting down the piston crown but only where it meets the transfers in order to gain back the lost duration.
anybody try this before? keith?

dave

av8tor1977

My Feedback: (6)

Hi everyone,

Wow, this RCU is great huh! Hey, I have a Kioritz GT 160 AE engine that after reading this forum I'm guessing is 16cc. (Haven't taken it apart to measure it). Can anyone confirm this size? CH ignition is expensive for my low buck project, so I'm going to stick with the mag. Any advice on how to make or where to find a prop adapter? What size prop would be good for this cute little engine? About what size plane would it fly? (I realize it's quite tiny for a gas engine, but I'm dying to try it anyway.)

Thanks,

Av8Tor

ZAGNUT

My Feedback: (1)

for some info on hubs search this forum for the "machining help" thread. if you keep the flywheel all you need is 30mm dia. alum rod threaded all the way through and long enough to replace the flywheel nut and still have enough threads left over for the prop bolt.

the 160 is indeed 16cc and would probably do good with a 14x8 or 15x6 wood prop. it would probably make the same or more power than the featherlite 18cc so see what they use.

echo recomends 32:1 mix for the 160 as opposed to 50:1 for their larger engines when using their brand of oil (synthetic?), maybe because this engine is lacking needle bearings on the upper end of the rod.

dave

Volfy

My Feedback: (23)

You'll find that the smaller the engine, that larger the weight of the ignition parts count in the overall percentage of the RTF package. My 25.4cc Kioritz engines weigh over 3lbs with magneto (bare engine is only 2lbs). I doubt your 16cc will be much less than that. If you don't want to go CH Ignitions, I suggest you convert it to glow to keep the weight low and get a much needed power boost. These needle bearing equipped gassers run great on 5% oil 95% methanol, so fuel cost is low and no more mess than if running on gasoline.

Otherwise, you'll end up with a 50 Oz. engine that has the same power as an ordinary .70 4stroke glow.

av8tor1977

My Feedback: (6)

Cool, thanks for the info guys. Another question. If I use aluminum bar stock to make a prop adapter, will the threads will be strong enough to retain the flywheel, and prop?? Also, is there any problem with the adapter coming loose when starting since the direction you turn the prop is in the same direction to loosen the "nut"?? (I'm thinking of it loosening when you start the engine, since you will be "whacking" the prop in the direction that would tend to loosen the flywheel attachment.)

I posted some pics of my wife with a plane of mine, and us flying on the beach here in Mexico in the "clubhouse" section under "something to be jealous of guys", in case any of you are interested.

Thanks again,
AV8TOR

av8tor1977

My Feedback: (6)

Also, interesting idea on the glow conversion for this engine. What type of oil, where to buy methanol, and where do I source a glow plug that size?

AV8TOR

mikenlapaz

Loctite everything. If possible drill some small holes in flywheel and pin adapter to it. Make sure it is bolt/nut is tight. It is not pleasant to have them come off as the engine starts! BTDThat!

mikenlapaz

go to alcoa web site for ideas on proper series to use. 6061 is not a good choice. Seems like maybe something in 2000 series

Volfy

My Feedback: (23)

About loosing your nut, it's the same thing with your glow engines, or most any RC engines for that matter. i wouldn't worry about it.

You use the same RC glow plug. You just have to get a plug adapter. You can make one from an old spark plug or you can buy one from CH Ignition or B&B Specialties.

I buy methanol from a local racing fuel distributor here. Ask around the race track in your area. As for oil, either castor or synthetic will work - same as regular glow engines. I always use at least some castor, but I may be old-fashioned.

av8tor1977

My Feedback: (6)

Sure appreciate all the help guys. Thanks a lot. One thing that bothers me if I keep the original mag ignition, is that the mag coil mounting up high seems to be right in the way of the cooling blast from the prop for the engine. Can I re-key the flywheel 180 degrees out, and mount the coil down low, or will this throw off engine balance?? Is the mag "zero balanced" and engine balancing handled inside? Also, what kind of voltage does the mag send to the coil in case I decide to design my own Hall Effect trigger system with a battery, and using the stock coil? Anyone know?
AV8TOR