Micro 12VDC Generator with a Cox .049 Sure Start Diesel Engine

Started the engine ONLY. NO GENERATOR. Used a tiny, around 3 inch propeller for high RPM spring starts. Bent the piston rod 20 degrees! Must get a new piston and piston rod from Cox.

What happened. Stay tuned for more. For now, only briefly :

1. A few months back, as posted, I attempted to start the engine with bad fuel ( bad oil ) and a heavy propeller with, most importantly, a POWERFUL mains connected electric drill. There were floodings. This was the same way and almost the same setup I broke the pin of the original Cox crankshaft. Davis Diesel crank is strong and did not break. Good news. Unlikely to have bent the pin although I do not have a way to check this accurately without a disassembly.

Most likely, the piston rod started to bend during these power drill starts.

2. Reset the piston very well, almost without any clearance. As mentioned by someone else in the forum, with high temperature this may not be a good idea. I will not reset the new piston and the piston will remain reset by the factory.

3. Used more powerful fuel with slightly more Kerosene. Unlikely this to be the reason.

4. The spring of the Fuel Needle Valve was very week. Thus, when the engine started, the Fuel Needle Valve started to spin. Had to be kept by hand. Did not adjust other settings and the engine worked at a huge power and speed. After the run, I pulled the spring to make the Fuel Needle Valve more stable in vibrations.

5. The engine ran hot. I think but I am not sure, the temperature expansion coefficient of the piston and the rod is greater than this of the cylinder, thus, when overheated, the piston may see a huge resistance from the piston. Looked at the cylinder and the piston for scratches. Did not see any, though.

6. Preheated the engine with a torch cigarette lighter before and during spring starts. Unlikely to be the reason but may. Was not very hot but the torch was pointed at the exhaust in a single point only. This point was hotter. Hopefully not much but may have been.

7. Did many high RPM spring starts with the tiny propeller. Some of them with flooding. Done this before. No problem. However, in case the piston rod had just been slightly bent from the power drill start, this may have contributed.

8. This is the first longer run with the Davis Diesel crankshaft. Was worried of tolerances and the hexagonal propeller plate and the clearance thereof. Everything looked perfect. Thus, the new crankshaft and the tolerances was not the reason.

9. I did too many screw ups.

Good to be back, though! Happy to wear the old spice balm and Eau de Cologne made of Ether, Kerosene, Castor Oil and Cetane Booster!

Also, been watching too many UFO documentaries to notice something I would like to share. UFO's are thought of emitting huge electromagnetic and electrostatic field, strong enough to stop a traditional car gasoline engine with a coil, distributer, spark wires and spark plugs. Realised Cox Diesel does not have any of these nor anything electrical. Therefore, no UFO would be able to stop a Cox Diesel Engine! They start and they run for as long as there is fuel.

oh wow
i still havent broke anything even though i start electric all the time

btw i started building my second diesel engine
and i got it to run
but i cant get the compression high enough (little misproduction in the diesel heed)
it is fun to recoil start a cox engine
and my own hardend crankshaft is holding up great

robot797 wrote:oh wow
i still havent broke anything even though i start electric all the time

btw i started building my second diesel engine
and i got it to run
but i cant get the compression high enough (little misproduction in the diesel heed)
it is fun to recoil start a cox engine
and my own hardend crankshaft is holding up great

Great to hear.

The power drill I have used is incredibly powerful and can rotate even the most flooded engine. The pressure on the parts is huge.

I can either use a battery powered one or this one very cautiously, only when there is no flooding.

Or don't prime it
Start spinning the engine and add fuel to the choke tube
Or block it for 1 sec to draw fuel
When I wanna start my generator I start spinning it and then I pressurize the tank for a bit
And then it starts

Wow, just discovered this, interesting and it's Gunna be a long read.

When it's time comes I will be making the glass fibre hulled perkasa MTB type RC boat.

I would need recoil start for the merci 61 glow engine but have thought about IC/electric as reverse would be easier.
Looking for suitable petrol engine, strimmer type again ic/electric as reverse needed, may be electric start also.
It's Gunna be a bit heavy but just thinking and making notes at this stage...

Coxfledgling wrote:Wow, just discovered this, interesting and it's Gunna be a long read.

When it's time comes I will be making the glass fibre hulled perkasa MTB type RC boat.

I would need recoil start for the merci 61 glow engine but have thought about IC/electric as reverse would be easier.
Looking for suitable petrol engine, strimmer type again ic/electric as reverse needed, may be electric start also.
It's Gunna be a bit heavy but just thinking and making notes at this stage...

have fun reading
its good to see that people find this interesting

Coxfledgling wrote:Wow, just discovered this, interesting and it's Gunna be a long read.

When it's time comes I will be making the glass fibre hulled perkasa MTB type RC boat.

I would need recoil start for the merci 61 glow engine but have thought about IC/electric as reverse would be easier.
Looking for suitable petrol engine, strimmer type again ic/electric as reverse needed, may be electric start also.
It's Gunna be a bit heavy but just thinking and making notes at this stage...

I would advise against diesel, unless, you have excellent, company made fuel. Even then, you may have a great difficulty to start the engine with the recoil spring. To use the recoil spring, you, best, use a glow plug engine, as you have said you would. However, when starting up, the engine should not have any load, electrical or mechanical. You may wish to think of a possibility to use an RPM engaging or a manual clutch.

Hi ssb,

My prefferance choice would be petrol fueled engine. My prefferance choice of electrical generation would be brushless 3 phase alternator utilising a rotating transformer for field coils control, hence controlled output, similar to vidio head and the Yamaha xs250 alternater.

Vidio players can yield useable parts as can hard drive motors but still formulating ideas and making notes.

The real work starts when at that stage with bench tests and runs, matching generated to load, control and probably many other "problems" to overcome.

This ic/electric method of powering this boat project is probably easier than a mechanical "gearbox" for reverse gear. Even thinking of electromagnetic clutches...

Some outboard motors use electromagnetic gear selection in the prop driver under water gearbox.

A long thread to read and lots to learn.

I reconment is getting a good brushless rc motor (it also can be the starter XD)
also keep in mind that if you want 10V at 10000rpm you need a 10Kv motor
the closer you are to the right voltage the easyer it is to store and use it

my diesel generator has a random motor but it spits out voltages between 30 and 60V
that is why I never powered anything with it

In larger model its possible To use a variable pitch propellers the prop is able To reverse the flow circulation without changing direction but For this smal engine ????

davidll1984 wrote:In larger model its possible To use a variable pitch propellers the prop is able To reverse the flow circulation without changing direction but For this smal engine ????

look up a kitchen rudder
it is way easyer then a variable pitch (and cheaper)

Well here is a beautiful invention I have already seen but without really knowing what it was wow sure i can use this system wil allow me to go back wit my boat if i want without to mutch trouble i can fit this system i tink

Adding a generator to an engine is the easy part. You now have to come up with some electronics to control charging the storage battery. Some form of throttle control for the generator relating to demand would also be desirable.

gkamysz wrote:Adding a generator to an engine is the easy part. You now have to come up with some electronics to control charging the storage battery. Some form of throttle control for the generator relating to demand would also be desirable.

boost buck converter set the amps to something the engine can pull
and set the voltage to something the batteries like

problem solved XD

What happens to the engine when there is no load?

gkamysz wrote:What happens to the engine when there is no load?

the rpm's go up

this can be solved by connecting the throttle to a arduino
it also solves the incresed load
if the voltage goes down the rpm goes up

Yes, arduino, I have not played with one of those yet but have played with basic basic c64. Went round and round for a month looking for info how to set port for input/output. Was given a c64 boom I had not seen before. Bingo, 2 lines of text and a worked example. Easy when you know how. An advance pelican crossing system ( walk/don't walk ) with traffic lights, pedestrian lights, warning audio, traffic flow piezio sender, ldr light sensor, pedestrian sensor, pedestrian request button and probably something else, I forget now.
Made hardware with some on board logic as insufficient Comms lines for a line in/out for each element. Software in basic. Really enjoyed that as all course content involved with the assignment. The college wanted it done on a 486 and turbo Pascal. The kids had 486's at home, I only had , a c64. Distinction pass, really happy.

Arduino are new to me, have to get starter kit and software for the laptop. My dear friend mo, lads school mate, is heavily into Arduino so can help out/advise.
He is making system for a car engine management and control. I want to make a more reliable ign system for a honda, possibly fuel injection as well, Arduino based but a self contained system not needing a battery. Spare empty poles on flywheel stator but need to consider boot up time and stuff like that.

We will get there. We both live in relatively isolated areas but have mail order.

We both love Cox stuff and similar.

All of these ideas are wonderful. I would like to stress, again, on some important points I have encountered :

1. Diesel engines are difficult to start. They may, when a special, company made diesel fuel is used. Just mixing off the shelf Kerosene, tractor start up Ether and pharmacy Castor oil will, probably, not start the engine. In case all of these components are made by companies, specifically, for RC diesel engines, than, probably, the mixture would work, but, general purpose components may not.

2. Diesel engines are difficult to start, just, with the spring. Variable speed, electrical drills or screw drivers may need to be used.

3. Glow plug engines are easier to start.

4. Any mechanical load will make the engine impossible or difficult to start. Even alternators without a load, variable pitch propellers or normal propellers when they are very long. On one hand, these introduce a fly wheel momentum, which, is good. On the other hand, they create mechanical ( or fluid mechanical ) resistance, which, makes the engine impossible or difficult to start and sustain. Thus, tiny propellers, used as cooling fans may be preferable.

5. Automatic or manual clutch are supposed to solve this problem.

6. The power, generated by the engine is very low, yet, may be able to charge a phone.

7. DC to DC, switching converters are a good idea. Efficiency around 90% is welcome. An on off switch is necessary. However, even when these are off, the alternator creates a mechanical resistance and momentum. Similarly to a big propeller, the alternator creates a fly wheel momentum, which is good, but, also, a mechanical resistance, which is bad. In this case too, better is not to have the mechanical load ( the alternator ) at all during startup, thus, a clutch is necessary.

8. I have tried a simple " clutch " : before startup, I oiled the belt, which drives the alternator. Thus, during startup, the belt is supposed to slip. After a while, the oil would be blown away and the belt will engage. Theoretically, this may work, practically, will not.

9. Electrical drill may solve most of the problems. Variable speed is OK. The engine may be turned slowly and the speed can be, gradually, increased. The problem is the minimum speed of the engine is much higher than the maximum speed of the drill. I do not know whether high speed drills are available, however, specially designed, electrical startup tools for RC engines are available. However, these must be able to generate high enough torque to move the alternator along with the engine. Also, these must be able to continue to rotate the engine a huge RPM and torque for a while after startup, so, the engine can sustain. Otherwise, the engine will startup and then stop. I do not know whether the available startup tools have the necessary torque and RPM to start and sustain.

10. Ether priming may not be used. When used, a very tiny, negligible amount should be used. Better without than with a wrong amount.

Also, there is a company, which, puts the whole system as a custom order. They select the engine, put an alternator, etcetera. However, they charge a huge price, yet, everything is guaranteed to start and sustain.

A better approach may be to use a chainsaw engine. Also, there are some Wankel, rotary engines, which are powered by methanol and the whole system is as big as a power bank and even fits in a pocket. They are made for cell phone charging.

StevenStanleyBayes wrote:

1. Diesel engines are difficult to start. They may, when a special, company made diesel fuel is used. Just mixing off the shelf Kerosene, tractor start up Ether and pharmacy Castor oil will, probably, not start the engine. In case all of these components are made by companies, specifically, for RC diesel engines, than, probably, the mixture would work, but, general purpose components may not.

This may have been your experience, but it's a bit of a generalisation. To be honest, I've probably had more trouble with starting glow engines than diesels. Remember that you're working with an engine which was never designed as a diesel. That's gotta be your first problem.

I first started the hobby with a Mills P75 when I was 11 or 12 years old and that thing was a first or second flick starter. When I got back into the hobby 10 years ago, the first thing I did was pull out my old Taipan Tyro 1.9cc diesel and cracked open a half full can of diesel fuel that had been sitting around for 35 years. Engine fired up easy. Mixed my own fresh stuff from ether, kerosene and castor and added a splash of diesel ignition improver. Fired up my Kumar K150 easy, no trouble with a Silver Swallow 1.5 or any of my operational Taipans.
Old fuel, home made fuel, didn't seem to matter. If the engine is in decent condition and is of a design which started out and ended as a diesel, they are not hard to start.

One thing I would like to ask Steven, is please don't continue to use a power drill or any type of electric starter on any model diesel engine. You will most likely flood the engine which will lead to damage. In my experience, draw fuel through by choking it just short of the spray-bar and add just one drip of fuel to the outside of the exhaust port and flick sharply. If it fires but doesn't start, check where the fuel is sitting in the line. If you see no air bubbles in the line, close the needle and try another flick or two. If you get no action, again place a single drip on the exhaust port and open the needle about 3 turns. If it fires and dies again, try another drip. Remeber, the needle setting on a diesel is generally not near as sensitive as a glow engine.

Also, don't expect a Cox spring starter to have enough strength to flick over a diesel. Again, it was never designed for this.

Oldenginerod wrote:

StevenStanleyBayes wrote:

1. Diesel engines are difficult to start. They may, when a special, company made diesel fuel is used. Just mixing off the shelf Kerosene, tractor start up Ether and pharmacy Castor oil will, probably, not start the engine. In case all of these components are made by companies, specifically, for RC diesel engines, than, probably, the mixture would work, but, general purpose components may not.

This may have been your experience, but it's a bit of a generalisation.  To be honest, I've probably had more trouble with starting glow engines than diesels. Remember that you're working with an engine which was never designed as a diesel.  That's gotta be your first problem.    

I first started the hobby with a Mills P75 when I was 11 or 12 years old and that thing was a first or second flick starter.  When I got back into the hobby 10 years ago, the first thing I did was pull out my old Taipan Tyro 1.9cc diesel and cracked open a half full can of diesel fuel that had been sitting around for 35 years.  Engine fired up easy.  Mixed my own fresh stuff from ether, kerosene and castor and added a splash of diesel ignition improver.  Fired up my Kumar K150 easy, no trouble with a Silver Swallow 1.5 or any of my operational Taipans.
Old fuel, home made fuel, didn't seem to matter.  If the engine is in decent condition and is of a design which started out and ended as a diesel, they are not hard to start.

One thing I would like to ask Steven, is please don't continue to use a power drill or any type of electric starter on any model diesel engine.  You will most likely flood the engine which will lead to damage.  In my experience, draw fuel through by choking it just short of the spray-bar and add just one drip of fuel to the outside of the exhaust port and flick sharply.  If it fires but doesn't start, check where the fuel is sitting in the line. If you see no air bubbles in the line, close the needle and try another flick or two.  If you get no action, again place a single drip on the exhaust port and open the needle about 3 turns.  If it fires and dies again, try another drip.  Remeber, the needle setting on a diesel is generally not near as sensitive as a glow engine.

Also, don't expect a Cox spring starter to have enough strength to flick over a diesel.  Again, it was never designed for this.  

Well, the engine is the same as any other engine. So, no, I do not agree. Diesel engines cannot start in general.

No, the electrical startup may not flood the engine, except, when lots of ether is used as a primer.

The spring of any diesel engine is the same, so, pretty useless.

You must have used special ingredients to make your fuel. Whatever they are, they may not be as good as the company made diesel. I have seen people start their diesels, somewhat, easier with a company made diesel, from a big, reputable company.

Here is the main problem : even in high temperatures, the diesel does not have enough compression and volume for initial startup. Maybe, some huge engines are easier. Not to mention liquid ether is freezing. Pure Ether may be better, but, such may not be available. Those for tractor startups have a very low amount of pure Ether to save money. They rely on the big volume and, somewhat, bigger compression of the real diesel engines.

So, no, I do not think you can start your engine easily. Certainly, not at all or with a great deal of difficulty when a dynamo or an alternator or any other load is attached.

Forgot to mention : either a very tiny propeller must be used or, best, a fan. The fan is, only, need to cool the engine and must not introduce any mechanical resistance. A tiny, RC propeller may be cut and modified ( symmetrically ! ) to make a fan. Even with a fan, the engine may not start.

Now, glow plug engines must, always, start, because the glow plug ignites the fuel and, automatically, sustain the ignition. A good idea may be to keep the glow plug on for while before start up. Priming helps in this case as Ether is easier to ignite with a glow plug. The only, nasty problem is glow plugs may burn when kept on for a long while, hopefully, they would be OK.

As a conclusion, no diesel engine and no special fuel can outperform the glow plug engine in start up. So, sorry to disappoint you, but, no. Diesel engines are useless and have no advantages over glow plugs. The largely spread news the diesel is more powerful are, also, not true as glow plug engines burn the fuel more fully and derive greater power.

So, you can keep using diesels as well as anyone else who wants, but, you and all others will have greater troubles. Therefore, to save you and all other the problems you all will encounter, I have a few words : similarly to a car engines, diesels are useless and have no any advantage.

In regards to car engines, some people think diesels derive more power per cost. This is, also, not true. A gasoline engine, made to be the same as a corresponding diesel engine, will derive more power and through a suitable transmission more torque. The reason is simple : diesel engines combust immediately, thus, destroying the engine. This is why the make stronger and bigger diesels to handle the knock. Gasoline engines, when supplied with high octane fuel, burn the fuel throughout the whole stroke of the piston and spread the power throughout the whole movement of the piston downwards. Thus, they generate much more power and torque. However, to save money and weight, the designers make them more fragile than diesel and this is where the general misunderstanding comes from. However, again, exactly the same diesel engine, converted to gasoline will make more power and more torque.

The problem with the diesel myths is the US : they use 87 octane gasoline, which, is kinda, diesel. Gasoline must be much higher than 100 octanes, 104 or even more in order to work properly. Most of the world uses 93 to 96 octanes to save money. This is also incorrect. 102 and 104 are largely available in Germany. This is the correct fuel, even, more octanes are needed. Natural gas has an octane number in 120's. Air fuel ( Kerosene and better ) 150.

There is only one reason for diesel engines to have, ever, been used : diesel used to cost half of the price of gasoline. Now, this is not the case and they do not exist anymore, not in cars with a few exceptions in Europe, mainly in Germany, although, they, also, try to stay away from them.

The same applies for RC diesels, although, they are not real diesels ( they do not burn real diesel fuel ) the principles are the same.

The said engine is designed for diesel as much as any other in the main principle. Even better, this engine uses light and tiny components, which, makes this diesel conversion engine, even, superior to the so called " real " diesels, designed for diesel. The compression is the same or, even, bigger and so is the size, compared to the same or similar " real " diesel engine.

So, to summarise : no diesel in any case, RC or not RC!

However, I like enthusiasm and I would like to take this opportunity and wish everyone who uses diesel engines good luck.

StevenStanleyBayes wrote: So, sorry to disappoint you,

Oh, my only disappointment is that you are unwilling to listen to any advice, even that which is intended to help you. If you believe that I have merely fabricated my experience with diesels, then feel free to live with your illusions.
Signing off!!

I do not want to start a diesel vs gas car engine dispute here, just share my experience... I feel that the general statement that diesel model engines and diesel car engines are useless is a bit of an overstatement, so  I take the liberty of having different experience  than  Steven's statements on model and car diesel engines.

1. Back in the time when I was 12 years  young  (52 years ago) I met my first 1.5ccm "diesel" model engine, a Hungarian Moki I guess, that I could easily start by hand-flipping, fed with a 33%/33%/34% blend of pharmaceutical ether, petroleum and castor.( I did not even know that amyl-nitrate or similar combustion boosters were available for diesel model engines)  I used a hand-carved propeller I made from a pine wood block (!!! and praise my fortune that it did not split and fly splinters into my naked eyes   )  

I think it partly boils down to the proper fly-wheel momentum of whatever is mounted on the shaft of a diesel. And having a routine in handling the counter-piston of the diesel is also essential.. Diesels need more fly-wheel momentum for hand flip starts  than glow engines, but I think this is a no brainer.

2. The antique plane flier old-farts of my age in a club where I am a silent member all run their planes powered by 50-60 years old diesel model engines with no complaint of difficulty in starting them.

3. I have been driving diesel cars since around 2001, and cannot repeat enough how much more torquey and efficient I find them in comparison to gas engines of equal size. ( My 2 litre diesel, some 190HP rated output, consumed an average 6l/100km when I drove home last time from Holland to Budapest over a 1400 km distance that I covered in 12 hours with occasional pee-stops for my wife..in Germany I seldom drove below 180km/h as there is no speed limit there on most highways, the rest of the trip was covered  near 140km/h..so my priority was time and not economy, and I managed that at 6l/100km..a gas/petrol engine would have consumed at least 20% more than that, I assume....)

4. Regarding diesel car engine longevity, if you sat in a well used cab (VW, Skoda, Benz, Audi, Opel=GM etc.) in Europe you would quite often see the ODO of those diesel cabs are passing 5-600k km or even reaching 1million  km, on the same engine!!! They may be knocking and rattling but their state of the art dual-mass fly-wheel+clutch units are dampening the diesel detonation.

I also prefer glow engines to diesel model engines though: first off because I am a stock COX glow engine fan, and second, the diesel fuel for model engines is even harder to obtain nowadays than nitro for glow fuel.. Them not needing power to electrify the glow plug would also be a major advantage, though...

in my opinion
diesel easy to start
homemade fuel is the best (and the only one I can get)
ignition improver is not needed (never use it myself)
electric start can be done but lower compresion and minimal priming (make it start by incresing compression)
spring start is easy and the engine wont break when flooded
flip staring is great unless its a 10cc diesel (they HURT)
mechanical loads make almost no diverence on the engine
cox diesels have low compression but still run great (and powerfull)

and @StevenStanleyBayes
there is a reason you never finished your generator
you dont take the time to realy learn the engine
(also a belt driven generator isnt logical)