# World's Smallest Diesel Engine



## DAKSY (Mar 3, 2014)

I am a machinist by trade & on my BEST day, I couldn't fabricate everything this small, assemble it & make it run...

http://www.wimp.com/tiniestengine/


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## begreen (Mar 3, 2014)

Pretty amazing. No oil sump?


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## Warm_in_NH (Mar 3, 2014)

Seen that before. Having spent 12 years of my life in machine shops, much of it small diameter, this still blows my mind.

Obviously it can be done, but the time and detail that went into it are very impressive. 

I love that it's final running shot is clearly on his dining room table. Someone with a lot of talent who can't sit still.


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## fossil (Mar 3, 2014)




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## velvetfoot (Mar 3, 2014)

It's a V-12!


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## Adios Pantalones (Mar 3, 2014)

This is one of those things that I wish I could show my dad. Completely awesome.


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## begreen (Mar 3, 2014)

There's over a half year of labor into that tiny engine. Quite remarkable.


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## jatoxico (Mar 3, 2014)

That's great!


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## FanMan (Mar 4, 2014)

Quite a piece of work, but I was disappointed to see it only running on compressed air... not a diesel at all.


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## tigger (Mar 4, 2014)

I just watched that entire thing......my wife thinks I'm completely blown out......

She does think it's amazing that I found an entire forum of people who are like me........


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## razerface (Mar 4, 2014)

Beautiful!  I was surprised he used so many slotted screws


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## begreen (Mar 5, 2014)

And not a torque screwdriver in sight.


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## _CY_ (Mar 5, 2014)

amazing .. all by hand and no CNC .. learned a lot of techniques watching the detailed set of videos
http://www.youtube.com/user/yesuswilder10/videos


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## ironpony (Mar 5, 2014)

FanMan said:


> Quite a piece of work, but I was disappointed to see it only running on compressed air... not a diesel at all.


 

I knew it could not be diesel, no injectors. I was thinking RC engine fuel, that burns good in little engines like that.  Spinning on compressed air, means the timing etc is not so critical. Yes it was a lot of work, but it is not a running engine. Big difference between spinning with compressed air and running.

I know I am sounding like a ^&*%, but I was prototype machinist in the R&D lab for an aerospace company. In 9th grade my class project for the year was to build a steam engine. I did all the drawings, made all the patterns, cast and machined all the parts. Assembled it and it ran on its own. Last I was there the shop teacher still was using the drawings and patterns for the class.

For 10th grade the metal shop and auto shop teacher challenged me to do a cut away of a 4 cyl chevy engine, including all the components. That project took 2 school years to complete and is still there today for students to learn on. 

I have components that have been to the moon and back, and a few spread out over the country side, (Challenger accident) RIP astronauts, some are sitting at the bottom of the ocean F14's,A6's etc that did not make it.


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## jharkin (Mar 5, 2014)

Wow Daks thats just amazing thanks for sharing.



ironpony said:


> I knew it could not be diesel, no injectors. I was thinking RC engine fuel, that burns good in little engines like that.  Spinning on compressed air, means the timing etc is not so critical. Yes it was a lot of work, but it is not a running engine. Big difference between spinning with compressed air and running.



Traditional RC enigne fuel is a mix of methanol, nitromethane and oil. Uses a platinum coil glowplug for ignition that is missing here.  There are also model diesel engines - those burn a 3 part mix of kerosene, ether and castor oil and actually use a plain carburettor and relatively low compression.  That might work here.  In either case you can get away without the oil sump like Begreen noticed.  We have model 4 stroke engines and they just run high oil content fuel and rely on piston blowby to lubricate the bottom end.

Ive seen some pretty crazy engines for R/C vehicles... but nothing quite this small and intricate.  There as (might still be) a company that made a miniature flat head V8 and a custom 1/4 scale R/C ford T bucket to run it in, blowers and all.  But that was a lot bigger than this (EDIT: they are still around - http://www.conleyprecision.com/)

I also heard of somebody who built a working 1/5 or 1/4 scale Rolls Royce Merlin V12 engine for a scale model of a P-51 Mustang.  No idea if it ever flew.


Smallest working engine I ever saw that ran on real fuel is the old 0.010 cubic inch Cox "Tee Dee"  Bet at least one of us on here had one in a u-control plane as a kid....


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## ironpony (Mar 5, 2014)

JT, not sure if it would be splitting hairs but the old JD's ran on kerosene and used low compression with spark plugs. Not considered a diesel, so would those small engines you are describing be a diesel or just run on kerosene/ether mix which probably makes it capable of firing on low compression.
as for the OP the engine spins on compressed air, it is not running on fuel.

I did have some of those small Cox engines, .010 and .049, they were fun. We used to mount the engines with props backwards and make cars out of them, airboat on wheels. Had my share of cut fingers from props too.


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## jharkin (Mar 5, 2014)

ironpony said:


> JT, not sure if it would be splitting hairs but the old JD's ran on kerosene and used low compression with spark plugs. Not considered a diesel, so would those small engines you are describing be a diesel or just run on kerosene/ether mix which probably makes it capable of firing on low compression.
> as for the OP the engine spins on compressed air, it is not running on fuel.
> 
> I did have some of those small Cox engines, .010 and .049, they were fun. We used to mount the engines with props backwards and make cars out of them, airboat on wheels. Had my share of cut fingers from props too.



They are diesels in the sense that they are true compression ignition engines.  They don't have much in common other than that to a conventional diesel in a car or truck or boat.  They are or where really popular in Europe because traditional methanol/nitro model airplane fuel was very expensive, here in the states they are rare and the most common ones you would see are conversions by a company called Davis Diesel Development that would replace the head on a2 stroke alcohol model engine with a diesel head that had a compression adjust screw in place of the alcohol glow plug. The alcohol engines run around 7 to 1 compression, these model diesels are higher than that but not as much as the 20 to 1 of a big diesel I think, hence the use of ether. I think the ether also helps atomise the fuel since they are carbureretted not injected. AFAIK timing was adjusted via the compression screww, but I never ran one.


Interesting on the JDs... So those old Jonny poppers ran kero?


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## ironpony (Mar 5, 2014)

yes, you would start it on gas get it up to temp and switch over to kero. 1 gal gas tank 12 gal kero, kero has more btu's so more power.


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## FanMan (Mar 7, 2014)

The world's smallest true diesel engine probably was the Davis Diesel conversion of the Cox .010, which replaced the glow head with a new head incorporating a contra-piston.  I had one of the .049 versions.

The engine shown here, running on compressed air, would be closer to a steam engine, running on an external pressure source.  I built a couple of steam engines when I was in high school, one was a conversion of a Briggs & Stratton engine with a reground cam, the other was made of various sizes of brass tubing soldered together, with a slide valve.  Tested both on compressed air before running them on steam.

Dana


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## blades (Mar 9, 2014)

have a cox .020 & 049 floating around here,  plus a few more from back in the 60's


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