RE: Substitute for Ether
 

Hi Andy,

Really thank you for the help that you giving to me, im really appreciating..

Im converting a K&B .61 engine(all alloy construction, no iron) to run diesel, im machining a new head with deslocated contra-piston system. And i would like to use a certain fuel to test this engine, for i don´t have the doubt if is my project that is not working, or if is the fuel that is not working.. :eek:


When you talk of "oil", do you mean diesel or Castor/Mineral oil? Did you substitute the diesel by kerosene in full?

And did you tried put a small amount of gasoline in carb to first start? No results? Because in my mind, when you put gasoline in a overcompressed engine, the gasoline will enter in combustion very easy, because in a commom spark engine, the max compressio ratio that normal you can run is about 10:1.. then, i presume that when you put a gasoline in a non-spark engine with 22:1 of compressio ratio, it´s will enter in combustion very easy, by pre-detonation.. Am i correct?


Then, the basic formula that you suggested is: 78% kerosene(or diesel ?), 20% oil(castor, mineral.. 2 stroke oil ??) and 2% of cetane booster(is it easy to find? I usually find easy octane booster, that have the same smell of thinner) . I will try this mix to begin.



Ah.. and about WD40.. do you mean spray it in carb, or use the liquid form of it? WD40 is easy and cheap to find here.. :D



Cheers and thank you again,



Matheus

RE: Substitute for Ether
 

Gasoline will ignite in an overcompressed engine. The mixture has to be just right. It does not substitute ether. Besides most model engine are not near 22:1. The best property of ether is that it will burn in a wide range of mixtures. That makes model diesel easy to start when the normal 20-35% ether is mixed in the fuel.

I have run gasoline without ether. I do not recommend it. It's very hard to start and run.

You need:

Lubricant: Castor oil, mineral oil, synthetic, in order of preference. If the engine is of lapped design or you want the engine to last forever it must be castor.

Kerosene: Kerosene can be a variety of things but kerosene, lamp oil, charcoal lighter fluid, diesel fuel, stoddard solvent, among other things will work for the "fuel" component of the mix. It is important that it has a self ignition temperature of 200-220°C. Lower self ignition temperatures and boiling points are better.

Ignition Improver: Amyl nitrate, octyl nitrate, methyl ethyl ketone peroxide, and other things typically up to 3% will improve the way the engine runs. Start with a little and adjust until the engine runs well. You can leave this out all together many engines will run just fine without it.

Ether: Diethyl ether. As has been said if you want normal handling of a model diesel 20-35% is absolutely needed. By normal I mean start and run on the the same fuel.
A hot engine will run without it. The engine is harder to adjust, makes a little more power. It doesn't run quite the same as fuel with ether. The engines that I have run on etherless fuel have started on regular 35% ether mix to warm up, then run on fuel without ether. The best compromise, if you can get ether at all, is to make a small amount of starting fuel with 30-40% ether and fly on 5-20% ether. It still gives the cost savings, but improves handling quite a bit. if you can't get ether, I'm not sure. With a starter you can probably get an engine started on etherless fuel. But it will take quite a bit of compression and just the right needle setting. If you are not adding any ether you must add ignition improver, again experimenting to see what works.

RE: Substitute for Ether
 

Matheus,

I'm glad to help, truly.

I've owned a K&B .61 (ABC) as glow and it ran well and was durable. As diesel, you should consider the strength of the crankweb and pin and the sturdiness of the rod. I can't check those aspects as I no longer have mine.

Pictured, you can see the results of converting the Veco/K&B .19 to diesel. The crankweb broke at the pin. Pictured also is the crank from a K&B .21 which was installed and you can see the difference. You may have no problems with your conversion but in your best interests I felt compelled to mention it. As I recall, the K&B rod was of a robust enough design.

Oil refers to Castor or non-detergent (50?) Aviation oil. The Castor has been found to have ignition enhancing properties, I don't know why. You shouldn't use Pharmacy castor, you should use Klotz or Castor oil made for gasoline and methanol dirt bike engines and such. I use Klotz and it's of high quality and WILL blend with kerosene without ether. The only issue is if your fuel gets cold and this will cause the castor to drop out of the mix. As you never see below 12C, I'm sure you'll never have this problem.

I didn't try gas as a prime mix. I don't think it would work but you never know. Gas has a high octane rating which is the opposite of cetane. Octane means the tendency NOT to self ignite by compression. Gasoline engines are designed on purpose to ignite ONLY when the spark plug fires, so I don't think gasoline will be of any use in your diesel project.

I'm sure you have sources for Fibreglass resin. This uses MEKP as the catalyst. MEKP can be used as a cetane booster but be aware that it IS dangerous to the eyes. Even the smallest drop can do harm. Mixed in fuel it's highly diluted but in any case, it's not good to get fuel of any sort in your eyes.

May I suggest that you try the 78% kerosene, 20% oil and 2% MEKP. I've never used truck diesel and there has been some discussion about it for and against. Get kerosene if you can. Maybe you can get Lamp Oil? Pharmacy Castor may be used for a short time but as it is not de-gummed, extensive running with it may produce much carbon. We get lots of carbon already with our diesels so it may not matter.

With this fuel in the tank and as your prime, heat up the engine cylinder head with a heat gun or torch. Don't melt anything [X(]

May I suggest the following procedure. Run your K&B on glow fuel first, 5% nitro or even no nitro is fine. Break in your engine and adjust your carburetor at the same time. The glow settings on the carb will be close to what you'll need.

Then, with NO fuel in the tank, back off your compression screw to a low compression setting. Heat up the engine until it is very hot, too hot to touch. Apply three or four DROPS of prime and apply the electric starter. If the prime doesn't fire, increase the compression ratio a small amount and try again. You can do this three times before being concerned. The concern is that unburned prime is accumulating in the case setting you up for hydraulic lock and a bent rod or worse. If you don't get ignition at this point, tilt the engine with the exhaust pointing down and flip the prop a dozen times. You are trying to clear the case of any excess fuel. At this point you can apply the starter to it for a few seconds to complete the process.

Repeat the preceding until you can consistently burn off your prime. Throughout the starting procedure, remember to keep the engine HOT. Now fill you fuel tank and if you have clear fuel line, draw fuel up to the carb by choking and flipping.

Your engine should now start and keep running. For the first minute don't touch anything but listen to it carefully. You will likely be overcompressed especially as the engine comes up to operating temperature. You always want it to run for a minute or more to make sure the temperature stabilizes.

Now back off the compression screw, (less) and you should hear an increase in RPM. Do this until the engine slows a bit and then tighten it up to that sweet spot where it runs the best. Now pay attention to the needle valve. Unlike glow engines, Diesel engines can run too lean without much damage for a short time. You may be lean OR rich from the glow setting, sometimes it's hard to tell by the sound with a diesel engine. Just play the needle back and forth for maximum RPM. Once you have that, let the engine run for a minute and then adjust the compression again for more power. There is an interaction between the needle setting and the compression. You need to tweak both back and forth a few times to get the best setting.

Once you have those settings, you should not need to change them to start and even run the engine in the future. ONLY if you change your fuel formula OR you go from 35C down to 12C will you need to adjust both settings to any large degree.

Your mention of WD40 brings to mind that at one time, I did note that I got a prime run using it one time. I don't recall the engine or circumstances that this happened but I think it's worth a try. Perhaps 40% oil and 60% WD40 would be a good prime mix. The extra oil would give you good compression seal.

And that reminds me that you should be converting an engine that has good compression seal to start with. This is very important. Many do conversions to worn out engines because they don't want to risk breaking them but this is the wrong approach. You do need a good engine for this to work.

Hope all of that helps in a most worthy project. Keep us posted with your progress.

RE: Substitute for Ether
 

Andy,


I owned a HB.40PDP engine that had a similarly designed crankshaft, with the 'crescent' counter-weight...

It was my first 'real' engine (I consider Testors/McCoy and Cox .49 engines to be 'unreal'... and they also have the same crankshaft design...) and I managed to do the exact same damage, by using a Sullivan starter to attempt spinning an apparently hydro-locked engine...


This was not a Diesel, but a normal glow engine.


I fabricated a new crankshaft, that had a normal, 'anchor' counter-weight. It worked.
I managed to bend the rod back and it worked too.

RE: Substitute for Ether
 

Andy and Dar Dars "hydro lock" theory is most likely what occurred with the small area between the head and piston on some diesel conversions the engine can load up at an idle
with fuel in the crankcase when throttle is opened this slug of fuel may be enough to hydro lock the engine, this did occur on my irvine 25 conversion breaking the wrist pin and the damage continued from there taking out the liner and piston with severe scoring of both this engine had been running fine and it did happen after an idle for a period a extra head gasket may have prevented this but again only a guess martin

the crank and rods on irvine are pretty massive the wristpin is hollow
the engine was always hand started so hydrolock when starting was not the issue it failed when speeded up
my guess squish band area volume too small the engine has beev repaired and will put in 2 head shims have ordered a couple and will re run when installed

Also not being a machiinist I have relied on Davis heads for my almost all my conversions and sucess rate 100% with no failures save one when my MVVS 40 lost a c clip on the
piston the parts were replaced by Just engines it appears the groove on the piston was slighty under cut thus seating of the clip is not solid the new piston retained the clip with a solid
snap when installed and the engine is trouble free this was just a quirk and can happen a rare event on any engine

ON the fuel issue Davis, Burford, Pe Reivers, PAW, MVVS, Clutton all agree STANDARD ether mixes work without issues so much on that

RE: Substitute for Ether
 

Martin,

In fact, this engine failed in the middle of its second, 6 ounce tank. It ran well while it ran. Once I had the better crank and rod installed, it ran for an additional 2 X 6 ounce tanks to test for durability and all went well. It was done just to meet the challenge of dieselizing a non schneurle engine. Unfortunately, the new P/L set I got for it was quite mild in fit. I would have preferred one that was decidedly tight that I could break it in properly. It runs well but I'm sure it could deliver more power. On glow it's a honker.

About fuel and commercial mixes. What holds back a lot of potential converts is the very poor availability of diesel fuel. I'm in Toronto for a few weeks and I've called every single hobby shop and none carry diesel fuel, not a single one. Toronto is Canada's largest city, some 3 million or more. A substitute for ether was an attempt to allow the newcomer to get/make fuel more easily. There IS no substitute if you want your engine to do everything and that's that. But it seems that Matheus has zero possibility of getting ether from any source, even spray cans. So we try to help him in his diesel project. Who knows, relentless experimentation might get us to a place we never knew possible.

When I get back from Toronto, I'll try and do another run and post to YouTube. That may take a few weeks.

OK, I'm off to AJ Hobbies in Markham to see what I need,,, that I didn't know I needed it,,, till I saw it. You all know how THAT goes.

RE: Substitute for Ether
 

Hi Andy,

thank you again for all explanation.. I folowed all of your tips, in except of cetane boost, that i don´t found... is it crucial? I did a mix of 80% kerosene and 20% Castrol castor oil(very expensive this oil.. killed my pocket).

I got the engine hot, circa 100 celsius degrees, keeping a fire flame near of engine head.. then, i tried start using a eletronic starter(Hobbico 90), and it´s don´t have strenght to turn(turn very slow).. then, i tried by hands.. and no result..

Now, i don´t know if is my project that is not working, or if is the fuel without ether...

Ah..i tried used WD40(not this brand, i used Loctite SuperLub spray, that have same application), and no result too..


I think the compressio of engine is very good.. but sometimes, when i try turn to start, the engine "loose" the compressio and turn easy.. is it normal? Is it signal of engine burning the mixing and near to start?

I hope it is not internal failures..[:-]


Is a K&B .61 ringed engine, with mid-life..


Ahh.. other doubt.. my engine uses a high rpm tuned pipe(short manifold) and have worked windows(higher duration)(when glow, this engine turned a 11x6 prop at 14.700rpm).. is it affect diesel working?




Cheers and thanks for all help,


P.S: This is the thread of my engine project: http://www.rcuniverse.com/forum/m_62...tm.htm#6278147




Matheus

RE: Substitute for Ether
 

Matheus,

A ringed, diesel conversion. Now THAT I never thought to try. Reason is that the only ringed engine that I have, is a wonderful Webra .32 and this one has a Dykes ring. With no electric starter, it's hard to start. Only when cold with a load of oil will it snap over and start on a prime. Hot, it needs a starter every time.

So, a well run standard ringed engine may be giving you some problems when hand starting. The only other thing I can think of is that your head leaks compression somewhere.

In any case, I'm afraid that you'll have to get an electric starter that will spin over your engine strongly although I would have thought any standard starter would turn over a ringed engine easily.

BTW, thanks Dar, for the heads up. Duly corrected.

RE: Substitute for Ether
 

Matheus,

Forgot to respond to the question about the necessity for cetane booster. YES, it helps a great deal. I can't recall if I had any luck with just kerosene and oil. You must have diesel engines in Brazil, they can't ALL run on ethanol, can they? Anyplace that sells diesel fuel for trucks should have cetane booster.

It just occurred to me, this moment, that I was told by Jack at AJ Hobbies that diesels don't work well when you get up too far in size. Forgot what size he referred to but believe it was anything above a .40?

What about that, guys?

Maybe the OWT that big diesels don't run well , is something that needs to be looked at. There may be a fuel issue, my suspicion is that with the really bigger engines, lots of ether or cetane boosters may not be a good idea. Come to think of it, I wonder if that had something to do with my gasser blowing the case when it fired off.

More back burner stuff for when I get back up to full speed.

RE: Substitute for Ether
 

Yes, I agree that too much ether in a large diesel might not be the best thing. Experimentation will tell the truth. I looked over some numbers for am ST .90 conversion on DDD's site and it appeared to make less power and torque as a diesel. The heating due to compression is better in larger cylinders, this accounts for tiny 0.1CC needing at least 40% ether. SO the opposite must be true to a degree in the other direction. Excessive ether would result in backing off on the compression ratio and the associated drop in power output.

RE: Substitute for Ether
 

I had a look at the MSDS for the Super Lub. It's hard to tell what it is. The msds seems to list a proprietary mixture as it is not specific.

This might be raw fuel in the cylinder washing away the sealing oil. It could also be a sticking piston ring.

What is exhaust duration? Raising the exhaust port will reduce the maximum compression ratio that can be achieved.

If you are not using ether you must use some ignition improver. Please refer back to my post above. I do believe that Andy did get an engine to run on plain kerosene and oil, but I don't think it worked well.

You must use a starter to start the engine without ether. If the engine is above 60°C it should run on kerosene. The needle valve must be set very close. Start closed and gradually open the needle. If you flood the engine the first time, turning the needle does little good. Start the engine at 1/4 throttle.

RE: Substitute for Ether
 

-ugo

RE: Substitute for Ether
 

Greg,

Good point about the needle valve. With glow, the norm is to start off rich and lean out. With diesel, this might really hurt. Starting lean means you'll not likely load up on fuel as you work to find the right mixture. The diesel, unlike gow, will run safely for a bit when overlean. But that doesn't mean that it's a good thing either. Just not as dangerous.

As I mentioned, I'm in Toronto, as big a city as you can get in Canada. I've searched on the net, asked by email, inquired at gas stations and hobby shops and even contacted the University of Toronto. No one knows where to get B100 Biodiesel. I can make it but what AM i making, I have no commercial product to act as a benchmark.

Any of you Torontonians, if you have any idea, please let me know. We're here for two more weeks.

BTW, I DID find a source for Denatured alcohol. It's ethanol spiked with 15% methanol to keep you from making real cheap liquor at home.

This is another idea for a hybrid fuel but IS a departure from the OS product. And I'm just plain ole curious to see what the difference is between ethanol and methanol when run on the same engine and formula.

RE: Substitute for Ether
 

Andy I tried B100 and had poor results with it.

Also as to the 40% either for small engines: I have been doing quite well with my clan .098cc on regular Davis plane mix which I don't think has 40% either but it does have a nice pistion liner fit.. I always start that with an elcetric starter though. I don't think it is possible to start it by hand - at least I can't...

RE: Substitute for Ether
 

Re the B100. I'm willing to pay shipping cost for a few litres. Can you link me to your source? No Hazmat, I'm told.

RE: Substitute for Ether
 

I just buy it at the station around the corner.....

Their name is Pacific Biofuel and I'm sure they have a website.

Here it is:

http://www.pacfuel.com/

I could get you some if you need me to.... It doesn't burn too well in model airplane engines though...

RE: Substitute for Ether
 

http://modelenginenews.org/faq/fc_diesel_ops.html

Information about fuel for fixed compression engines. While not specifically useful for our discussion here, it has some tidbits that might be interesting to some.

RE: Substitute for Ether
 

Thanks Greg,

The article explains some of my experiences with using 40% ether, 40% kero and 20% oil. Using that fuel, a worn out Norvel .15 would run beautifully using just a disk under the head and exactly ONE copper gasket. I installed three or four and kept deleting till I had a good run.

This engine was worn out and even when cool had little snap over. Applying LOTS of high ether prime, (the fuel) I could easily get a hand start despite that. The reason that it ran so well on just one gasket was that there was appreciable wear in the rod and also, the upper deck of the cylinder was a bit taller that the piston at TDC.

The interesting thing was that the engine was first run without a muffler. It started easily and throttled well. When I installed a muffler, RPMs dropped a bit as expected but throttling became less effective and reliable. Adding a muffler is like throttling with an exhaust baffle. This drives the high end lean and you need to open the main needle a bit. Despite having an adjustable mixture for idle, this didn't compensate perfectly and all the good went slightly less good.

Chevy,

I'm afraid that I've been preoccupied with some serious family issues the last half year or so. Otherwise, I'd have taken you up on your offer sooner. I may be clear this fall, so I may be able to revisit the Biodiesel experiments in a limited way. I still need to know how my homebrew fuel compares to the commercial product. And I must say that I meant to say that I'd pay for shipping AND the cost of the fuel. Not much needed, just a quart. Please PM me if you still have some.

RE: Substitute for Ether
 

ugo

RE: Substitute for Ether
 

Ugo, yes I saw that the author did not take into account stoichiometry, although he did mention that the most power was made just before the engine quit rich.

I'm not sure what he means about storing magnesium. Little if anything is made of magnesium, and I don't have any experience with it. The only thing I found in my searching is that water is a big issue due to galvanic action. I suppose storage issues refer to keeping as much moisture out as possible. Contaminated oils might also be a concern?

Andy, I thought it was interesting how he described the needle action of the ether only fuel and how some oils showed a tendency to prevent detonation.

RE: Substitute for Ether
 

Greg,

Yes, lots of ether as in 50% to 100% does some kind of magic that makes everything better. And so, we find that mineral oils enhance ether's properties. I have some Cool Power OIL that I've been dying to try. With kero AND Biodiesel. All in due time.

RE: Substitute for Ether
 

Hi Andy,
After a good deal of "messing about" I have come to doubt the use of castor oil in model diesel fuel.
Well... certainly in the percentages we use.

Whooooaaaa heresy !!!!!

I find that as the percentage of castor is reduced and replaced with an equal amount of something else then the engine starts running noticeably more smoothly. I think you also noticed this when using some modified olive oil... the engine appears to run that bit more happily.

Castor oil is not naturally able to mix with kerosene, it requires ether or else it seperates out of the mix. This being the case it might suggest that something which does mix naturally with the kero will behave differently. I am guessing here but I think..... the high level of castor oil has a slightly adverse effect on combustion. Is that due to the evaporation of ether in the hot engine ?

I wonder if the castor, which doesn't want to be in there with the kero anyway, has an effect on the vapourisation of the kero... which is noted as being a difficult fuel to vapourise anyway.

I sure as heck don't know for certain but I do SEE and HEAR the difference when the castor is reduced and substituted by i.e. modified olive oil.

I think you will find that mineral oil works O.K to replace some of the castor, but to my mind, the engine seemed to run somewhat hotter and with a drier exhaust than when sustituting some castor with the olive oil. My best results come from using castor, olive and mineral combined.

I was off flying again today and it was a good day... apart from forgetting to take my lunch !

Using a PAW .15 with RC throttle and a 2 oz tank I got the following...

1st flight 22 minutes
2nd 29 minutes
3rd 24 minutes.

Fuel was my 10% ether mix which just required a couple of primes with 30% ether fuel to start.
As usual the compression was 1/2 turn LESS than that needed for starting with 30% ether.
Once the engine starts it pulls the 10% ether fuel from the tank. About 15 seconds and the compression needs backing off 1/4 turn, after another 20 seconds or so the compression is backed off another 1/4 turn and it's ready to go.

I have NEVER had to increase compression with my low ether fuel mixes.

Differences in fuel consumption were due to the amount of time at full throttle... approx 50% of the total flight time on each flight. The engie would run well at full throttle, come down to 1/8 throttle for just stooging around and after several minutes would again pick up to full throttle, without any hesitation or barfing.

The "work" continues and the results are pleasing That's 1 hour and 14 minutes actual engine run time today and that makes 5 hours or so on this engine while using low ether fuel. I want to get quite a number of hours on this particular engine to prove it holds up. All being well I may start looking at 5 % ether then, that will be some time next year I guess as I want to prove each step down in ether content before moving to the next. The 10% ether content looks very viable (and also economical).

By heck, you sure started something when I read your first post way back when... it's been interesting so far and I have made headway ... from initial testing to extended flying :)

Reg

RE: Substitute for Ether
 

Reg,

It's been quite a journey for all of us and I'm much gratified that those such as yourself had been inspired to "give it a go" and dabble with fuels and oils and formulas. As we've all proved, there's nothing new under the sun and yet, we've come to understand that there may be a better way than CURRENT established dogma.

Way back when I wouldn't have considered that the oil we used had anything to do with combustion. Lubrication, of course, but not combustion.

I'm hoping that this has also inspired the industry to do a little dabbling and if they could come up with a superior fuel at lower cost,,,, all the better for all of us. :D

RE: Substitute for Ether
 

This has been an interesting thread but I'm not sure we've found anything new, just ways to make our engines run on non-ether fuels. That said I was wondering if anyone has tried using Ethanol in with kero as a fuel that could work with a glow plug. The catalyltic action of the ethonal and platuim glow plug could replace the ether for starting. The ethanol should mix with the kero were methanol would not. This might give the power of a diesel with the cheaper and easyer fuel mix. Some of the guys that have run glows on diesel fuel might be the place to start. I don't know what concentration of ethanol we can get but I think something with say 40% pump ethonal, 40% kero and 20% synthetic oil (can't use castor as without the ether it doesn't like kero) might be a starting place.

RE: Substitute for Ether
 

There is a along long running thread in the Engine Conversion thread on running converted Gas engines with glow plugs and various mixes of alcohol and gas. see:

http://www.rcuniverse.com/forum/m_1267448/tm.htm

most promising mix for the gas engine conversions is to use 1 part 10% nitro 10% oil glow fuel to 3 parts (or was that 2 - I forget) premium gas and replace the plug with a glow plug. Many good reports.

Read the thread - it is long much like this one with many interesting insights and tidbits of info.

cheers, Graham in Embrun near Ottawa Canada.