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Electronic solutions to modifying glow engines of all sizes to gasoline

Old 12-31-2023, 01:51 PM
  #2051  
Raleighcopter
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Could cat's engine be running lean because it's cold and the ring isn't as tight as it would normally be?

Originally Posted by 1967brutus
Everything plays a role, but so far I have not yet seen much influence from an engine running 80 degrees HT all the way up to 135 (this is the range I pass when doing a tow, and it never requires any correction)So I think the main influence is fuel viscosity making the engine a bit leaner.
Diesel (only a slight bit more viscous than gasoline/oil mix) easily changes a half to a full point of CentiStokes on a tempperature change of say, from freezing to 20 deg C, and that is noticable in things like pumping speed or filter differential pressures.

So yes, I think the viscositiy is the main issue. But that is relatively unimportant, because both engine running temp and fuel viscosity are affected by the same parameter: ambient temperature.

It could be worth a try. You progged your own driver, it should be easy to do an experiment. Tthe nasty thing is, it takes a minimum of 6 months to change progging, test in summer, then wait for winter to check the veracity of the claim....

The 20 minutes WOT on 8 oz, I think is pretty close. I have a variable timer as an emulation of a fuel gauge, and it is set at 13,5 minutes for aprox a 25% reserve fuel. Since I can "tune" my fuel curve, this timer is "fairly accurate" regardless of throttle position. So I am inclined to say that yeah, you probably would be running 20 minutes on a single 8 oz tank.
Old 12-31-2023, 03:36 PM
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Originally Posted by Raleighcopter
Could cat's engine be running lean because it's cold and the ring isn't as tight as it would normally be?
Which ring exactly?
Old 12-31-2023, 04:49 PM
  #2053  
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Originally Posted by 1967brutus
Which ring exactly?
I was thinking piston ring. Are there other rings?
Old 01-01-2024, 02:16 AM
  #2054  
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Originally Posted by Raleighcopter
I was thinking piston ring. Are there other rings?
I suspected you would mean the pistonring (because indeed, what other rings are there?), but I don't see a connection between ambient temperature and ring sealing performance, great enough to affect mixture...
Hence my confusion,

I mean, the engine is running a bit cooler (Chris said he did not see the CHT above 120 deg C, while typically, mine reach about 135 in flight on a dutch summers day) but that means EVERYTHING is running a bit cooler in proportion.
Rings don't so much seal on their shape and dimensions per se, but more on the running surface being mated to the liner, and on the combustion pressure getting behind the ring, pushing it against the liner.
Just gutfeeling, but in this scale, and in aircooled engines I don't think that the influence of running temperature has any noticable effect on ring performance, to be honest.

I know that in the large marine engines, temperature changes affect ring performance but more in the sense of increased wear and greater chance of mechanical ring faillure. But the conditions under which those rings perform their task are barely comparable with what our rings encounter, both in absolute temperatures and pressures, as well as in the chemical environment they live in. What is more: Those engines have controlled linertemperatures (liner dimensions basically being constant), active piston cooling keeping the piston dimensions in check, while ring temperatures change with load, combustion temperature and pressure, and thus their dimensions vary, as opposed to our little aircooled engines where everything more or less expands or contracts a bit more in concert.

Mind you, I am just extrapolating here, because I don't think there is much research on this particular subject (plenty of that on the large engines, but very little WRT our toy engines), therefore as said, just a gut feeling, I could be wrong.

Last edited by 1967brutus; 01-01-2024 at 02:19 AM.
Old 01-04-2024, 08:34 AM
  #2055  
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Originally Posted by 1967brutus
I have mentioned this in the glow section as well, but I will repeat it here: It has all appearance that the ASP engines are making a comeback.
Your website name (sanyeengine.com)

IMHO excellent news because these engines have proven to be absolutely suitable for gasser conversion, and they were cheap enough to make a conversion directly from NIB cost effective compared to purpose built gassers like the Saito FG series. What is more: So far my ASP engines to this day still have a 0% score WRT mechanical faillures or even issues, and most of them even have a 0% score WRT deadstick landings.

So far, nothing has been confirmed yet, but I notified JustEngines, I should hear back from them soon enough.

Looking at the structure of the website (the product categories), it suggests that the new owners of Sanye are also considering gasoline engines, but nothing is mentioned about it yet, and of course it is anyones guess whether that will be new designs or simply adapted versions of the existing glow engines, or even if they are going to be "small" gassers (like typical glow territory) or if they will aim at the large scale market. Time will tell, heck, at the moment, it is said production has resumed, but nobody has seen any actual new production engines to begin with.

Now I woukd be highly surprised if Sanye would be the first manufacturer that would get carburation really properly right (not even Saito achieves what we achieve with our electronic conversions), so we still have purpose and application for the solenoid stuff, but at least, there will be affordable small fourstrokes again.
This rumour has in the meantime been confirmed as actually true. It is an entirely new company, nothing to do with the old Sanye, but they took over tooling, molds and rights to the name(s).

If I understood correctly, Both ASP and SC branded engines will be produced.

Let's just hope they won't skimp on quality.
Old 01-04-2024, 10:58 AM
  #2056  
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In their "about us" paragraph they state they took over S.Y. engine production in 2021... indicating "Southern Sanye" company was already an established business... possibly the same founders from the original Sanye company, just reforming under another business name... which would make sense, and being the original founders would have the production experience to manufacture these model engines... Otherwise, a new company learning the manufacturing process, there will be QC / manufacturing delays.
Old 01-04-2024, 11:44 AM
  #2057  
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Originally Posted by John_M_
possibly the same founders from the original Sanye company, just reforming under another business name... which would make sense, and being the original founders would have the production experience to manufacture these model engines... Otherwise, a new company learning the manufacturing process, there will be QC / manufacturing delays.
This is what I got from Andrew of JustEngines:

On a different note, I heard back from the new Sanye people. They are completely different from the original company but are beginning to scale production. They have told me they are going to deal with J Perkins only for the UK which is a bit disappointing, but we will stock what will be SC engines as they become available. We will also hopefully be able to source more spare parts.


So no, not according to him. I can imagine his dissapointment since he more or less was one of the biggest worldwide retailers for ASP.
Old 01-04-2024, 03:52 PM
  #2058  
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Originally Posted by 1967brutus
This is what I got from Andrew of JustEngines:



So no, not according to him. I can imagine his dissapointment since he more or less was one of the biggest worldwide retailers for ASP.
So I take it JPerkins doesn't ship internationally... I found two url's for jperkins / j-perkins , both selling hobby stuff, but not a lot of info on them other than they're exclusive UK / Ireland Distributors...


Old 01-05-2024, 10:03 AM
  #2059  
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Originally Posted by John_M_
So I take it JPerkins doesn't ship internationally... I found two url's for jperkins / j-perkins , both selling hobby stuff, but not a lot of info on them other than they're exclusive UK / Ireland Distributors...
Perkins is said to become the sole distributor of the ASP brand for the UK. As it is now, I did not see any announcement on their website, and their engines listed were dissapointingly few.
There will be different distributors in different countries is my guess.
The SC brand, I gather, serves for retailers that don't want to go through a national importer/distributer.
If I understood correctly, JustEngines CAN stock up on SC and SC branded parts, and like back then Magnum and ASP, these parts should be identical and exchangable.
But I would not be surprised if the US will have one, or possibly two distributers as well. As, would I expect, most larger EU countries.
Old 01-05-2024, 04:42 PM
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Thats what I figured as well... I would be suprised if Horizon Hobby becomes the North American distributor, but possibly Planet Hobby, they do import various hobby products globally... that's where I purchased the gaui f50 from.

I'm sure parts will be interchangeable, just have to see what their timeline will be on the 160... they do mention about improving enhancing the quality, which will be interesting to see what they come up with.

Last edited by John_M_; 01-05-2024 at 04:45 PM.
Old 01-05-2024, 04:59 PM
  #2061  
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They should build my controller and Chris's throttle body carb and they should give us free samples to test them out
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Old 01-06-2024, 04:53 AM
  #2062  
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Well, say what you will, but wouldn't it be great if the new company would, for example, rework the molds for the fourstrokes to have larger cooling area, add a magnet to the prophub and two threaded holes for a sensor bracket, and put some effort into developing throttle bodies?

I know there ARE allready a few glow engines out there, that have a fattened up sector on the front bearing seat, for apparently exactly that purose of fitting an ignition sensor.

Old 02-16-2024, 03:36 AM
  #2063  
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Hey guys, look what I got....

primarily for adjusting the carburettors of my bikes, but definitely going to try measuring the exhaust gas quality of our toy engines.
Not because it is somehow better, but because I would like to LEARN... which numbers make an engine run good, and which don't. What range of mixtures actually are "acceptable", what effect results from which modification, etc etc.

Most important of course: WOULD such a device be "usable" or not?
Remember folks, we're testing this so you won't have to

Haven't even unpacked the thing yet, but here's what I think: Most likely it will be pretty difficult to get consistent readings, and most likely an adapter of sorts will be necessary in order to get reliable and repeatable numbers.

But hey, I won't know unless I try, right?

It can take a while before I'll get around to it, but will keep you guys posted as soon as I have any data.

Edit: on the trusty old Ducati, it seems to work fairly decent and repeatable.

Last edited by 1967brutus; 02-16-2024 at 05:19 AM.
Old 02-16-2024, 05:27 AM
  #2064  
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That's pretty cool, Bert. Gunson also makes a product called "Colortune" that works good for getting jetting and tune close to optimal. Some final tweaking still required.
Old 02-16-2024, 07:16 AM
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Originally Posted by Glowgeek
That's pretty cool, Bert. Gunson also makes a product called "Colortune" that works good for getting jetting and tune close to optimal. Some final tweaking still required.
I heard about that, but not sure if I remember right... IIRC that is a glass sparkplug or something like that, right? That you can tune by the colour of combustion?

In a minute or so, gonna try if I can get a decent reading on my little gasoline powered launch.
5 cc (.30 cu.in.) at fixed 1500 RPM... Curious if that is going to work...
Old 02-16-2024, 07:33 AM
  #2066  
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Originally Posted by 1967brutus
I heard about that, but not sure if I remember right... IIRC that is a glass sparkplug or something like that, right? That you can tune by the colour of combustion?

In a minute or so, gonna try if I can get a decent reading on my little gasoline powered launch.
5 cc (.30 cu.in.) at fixed 1500 RPM... Curious if that is going to work...
Yes, you set the mixture by flame color. Blue with a occasional flashes of white seems to work as a good starting place. I hear Ethanolated fuel change the color perspective a bit but I have not tried that. I lost mine in a robbery along with a triple tier Snap-on chest full of Mac and Snap-on tools.

I look forward to your CO testing, especially results from one of your "tweaked for flight" conversions.
Old 02-16-2024, 10:34 AM
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Originally Posted by Glowgeek
I look forward to your CO testing, especially results from one of your "tweaked for flight" conversions.
First test with the small launch engine SEEM to indicate that the results CAN be useful.
At least, once I managed to figure out how to get a halfway decent reading with such tiny amounts of testable gas (about 1/6th of a cu. ft. per minute is not much), I also immediately learned that a change in setting, with this measuring principle, takes TIME to effect a change in readout.
I also learned that this engine too, needs several minutes to stabilize its behaviour after a change in settings.

The engine is externally governed, which means that when changing the needle setting, the governor immediately counteracts, so the RPM stays the same, the exhaust note stays the same, and tuning by ear becomes totally impossible. The only tell tale signs basically is the stability of the governor output signal (how much the throttle servo has to correct to keep the engine on set RPM).

Long story short, it took me about 10 minutes to get a reading I could thrust. It turned out that CO level was very high at 10% before adjustment.
It took 5~6 minutes of carefully manouvering with the needle to get the CO level down to 2,5~3%, and once that was accomplished, it took another 3~4 minutes before the new setting took effect and the throttle servo gradually became less nervous and active.
Exhaust effluent also became near invisible and a lot less smelly.

Going to let the engine cool down completely, then do a 2nd run on the same settings.
I expect a bit of a stubborn engine as long as it is cold, because I had the needle leaned out about 7 or 8 clicks, leaner than I can remember it ever was...

What can I say? It SEEMS to be a viable way of adjusting model engines, but I still have to figure out a way to get good exhaust gas sampling on a plane engine (I expect the propwash to be a practical difficulty to overcome).
Old 02-16-2024, 10:54 AM
  #2068  
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build a chamber that attaches to the exhaust pipe and connect the exhaust gas monitor to the chamber. make it small so there's less volume/dead time in the readings. make it big so there's minimal added backpressure to the engine. make it small so it travels easily. make it big so you don't lose it. i guess the only constant here is to make it. is that good enough direction/input?
Old 02-16-2024, 11:17 AM
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Bert, this is probably obvious to you but sitting here thinking, I ask myself, why would one of Bert's engines be running heavily rich? Do marine props unload? Does it vary with surface speed? Maybe the engine doesn't unload at all in the water at 1500 rpm? I mean, I can see running rich on the ground to compensate for unloading in the air but I honestly don't know the first thing about marine applications.
Old 02-16-2024, 11:52 AM
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Originally Posted by Raleighcopter
build a chamber that attaches to the exhaust pipe and connect the exhaust gas monitor to the chamber. make it small so there's less volume/dead time in the readings. make it big so there's minimal added backpressure to the engine. make it small so it travels easily. make it big so you don't lose it. i guess the only constant here is to make it. is that good enough direction/input?
All options passed my brain, haven't picked one yet...
The device claims to be "pumped" but actually it isn't, not really. It has a diaphragm chamber with non return valves, and it relies on the pressure pulses of the exhaust gas to make that membrane oscillate. The clicking noise indicates positive gasflow to the measuring cell. But the thing definitely needs something.

So most likely I will make something like a small T where the feed from the engine is opposite to the line towards the device, so the pressure pulses directly hit that "pump" thingy. Should not be too hard. More like it needs to be dimensioned such that I can hook up a great variety of different engine sizes.

I'll figure something out.

In all fairness, I expect the aero engines to run pretty decent. I more hope to be able to get some sort of "baseline measurements" from that, that possibly would allow to for example set curves such that CO levels remain by and large constant over the entire throttle range. But honestly, I first have to learn what kind of CO levels these engines feel happy with.

I don't expect needing one to set up my engines, but it COULD be that I will be able to provide additional info. I have seen a few people now that for one reason or another never managed to develop the "ear" to tune an engine. Perhaps for those it can be of help to figure out how to set up a fuel curve using this or a similar device.
It's not a cheap device, but also not prohibitive expensive. I don't know what these things cost in the US, I paid about 200 Euro. Fair bit of money, but I am going to use it on the Ducati as well, so I figured it was worth the money anyway.
Old 02-16-2024, 12:15 PM
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Originally Posted by Glowgeek
Bert, this is probably obvious to you but sitting here thinking, I ask myself, why would one of Bert's engines be running heavily rich? Do marine props unload? Does it vary with surface speed? Maybe the engine doesn't unload at all in the water at 1500 rpm? I mean, I can see running rich on the ground to compensate for unloading in the air but I honestly don't know the first thing about marine applications.
That is a good question, and the explanation is fairly simple: The engine is governed. It does not change speed or exhaust note when you adjust the mixture. So you won't hear anything.
It is literally as if you are blindfolded in the middle of a room, and you only know you're at the wall when you bump into it, but as long as all the walls are outside of arms length, there is no way of telling where you are: Left, right, centre, it's all the same untill you reach a limit and then the engine stalls.
Measuring the exhaust gas "quality" for the first time ever allowed me to make targeted adjustments.
The only thing I knew were "lean=> hard sudden stops" and "rich=>stops that more or less announce themselves" but inbetween, as long as the engine was running, no way of telling where I was. Because of the "lean hard stops", the natural tendency is to err on the safe side and that's how I ended up with a rich running engine.

Of course, there are tell-tales like the colour of the oil residue, or the pollution level of the spark plug, but those indicators literally take HOURS of runtime to reveal themselves, and are at best suitable for confirmation, not as a basis to make adjustments.
Old 02-17-2024, 09:56 AM
  #2072  
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That's a neat little co analyzer Bert... what did it cost you if you don't mind me asking... if it's accurate, will give you a lot of info on air / fuel mixture combustion efficency... I have one of snap-ons handheld 5 gas analyzers, only issue with using it on premixed fuels, you have to protect the probe end from the oil contaminating the tip... I tried it on the GF40 with the exhaust tube placed inside a glass jar and the probe end separated by some cotton wool... it seemed to work well, just the cotton slowed down the sensors response time, but for carburation, not really an issue.
Old 02-17-2024, 04:02 PM
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All in all with delivery it was about 200 Euro, and it's a single gas tester (only CO). But it is said to be maintenance free. No cleaning, filter replacement, wearparts or anything.
It has a built in moisture separator.
Stated accuracy is about 0,5% but it reads in 0,1% increments.

So far only tested ONE engine, but it allowed me to "adjust the unadjustable" from the get-go, and I learned a bit about fuel linearity that I had no way of knowing otherwise (this engine has "accoustic" carburation (fully analog, no solenoid enhancements or anything), and with a bit of luck, I will be able to get an improved fuel linearity by tweaking the air restrictor that maintains fuel draw when the throttle opens.

Without that restrictor, the carb lost draw when the throttle opened, causing the mixture to lean out and in turn this required an overly rich mixture at zero load. Not good.
The restrictor cured that as far as I could tell, but apparently I overshot the linearity a bit. Gradually opening the restrictor while repeating measurements might result in an even better tunability.
Old 02-18-2024, 05:33 AM
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That's a reasonable price Bert... the readings are + or - 5%, from the 1% scale, still accurate enough to tune with... any mention or precautions regarding oil vapor using pre-mixed fuels, or 2 stroke oil injection... the water separator will catch some oil vapor, but I would still take measures to protect the sensor from oil contamination.

It will also show a change in CO with base ign timing changes, especially with your custom cam profile grind & valve timing changes you made with that particular putt putt boat engine... post another video when you get it all setup, I enjoy watching your boat projects.
Old 02-18-2024, 09:12 AM
  #2075  
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Very interesting project branch Bert... I think this could be very helpful it finding the set on those hard to tune conversions. I have noted a few times that these conversions have a wide band of acceptable "running" adjustments that will only show secondary issues in the form of dirty exhaust or running changes with Ambient and engine temps excursions to high our low. The ability to tune and observe actual mixture conditions is a very good capability.

On the item of the sample not being actually pumped - do you think one of the little air pumps I use for tank pressurization might be of use?


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