I Make This Tiny 2-Stroke Engine From Scratch

today we're going to take a look at making this very small engine this is 0.1 CC's displacement that's 1/10th of a cc this engine was designed by Richard Gordon in the early 9s and it was published in the magazine model engineer in the UK as a build article this is a two-stroke engine and it uses compression ignition no glow plugs or spark plugs or anything it's kind of similar to a diesel though not exactly the same the construction of this engine is quite simple the only real challenge is the size of the parts being so

small the fit of all the parts to each other is very critical in getting a small engine like this to run there's really no room for sloppy work on an engine like this well that's enough computer stuff let's get out into the shop the first part we're going to make is a crank case this is one of those parts that when you look at it seems really complex but if you break it down into all its individual steps it goes pretty quick it's actually pretty straightforward to make [Music] I made up a threaded Arbor so

we can hold it to finish the front of the crank case for now in the milling machine this hole is where the carburetor will fit into well if we got somewhere to put the carburetor I guess we better make it this internal curve on the velocity stack was a good place to break out my Graver and do a little bit of hand turning the carburetor is finished it's just held into the crank Cas with a spot a Loctite back on that threaded Arbor we control the main crankshaft bearing we had to wait to do this

until after the carburetor was in there's just a few more operations left on the milling machine and here's the finished crank case I filed the bottom round off camera just to save you a little bit of TDM the piston and counter piston are made from hard cast iron this little piece will be enough for both of them here's the Piston all finished off and I made the counter piston pretty much the same way the cylinder is made from the same type of cast iron as the Piston is even though I've done it more times than

I could ever count single point threading is still super satisfying sh this setup in the milling machine is using a custom cutter that I made to cut the exhaust ports and this here is the transfer ports and that's all there is to the cylinder I use some oil Stone powder to give it a quick hone to fit the Piston the connecting rod is made from 6061 aluminum I used the milling machine to cut it roughly to shape [Music] then I made up some filing buttons and got to work with a handful of files and here

it is finished the crankshaft is made from 1144 stressproof steel this steel is pretty tough and it machines really nicely it works good for crankshafts for I'm using an offset bushing to turn the crank pin this makes for a very strong crankshaft the alternative would be to drill a hole and press a pin in but that interface is a weak point and especially on a small engine like this they runs really fast we need just about the strongest crankshaft we can manage here it is finished and I might have forgotten to start the camera recording

when I drilled the intake ports whoops we've got most of the difficult work behind us now so it should be pretty smooth sailing through to the end the cylinder head is a simple part made from 6061 aluminum [Music] and here it is after anodizing now we're going to go ahead and make the back plate this part covers up the back end of the crank case these two slots will let us use a spanner wrench to tighten it to hold it to finish the other side I'm going to use a superglue Arbor and that's exactly what

it sounds like we'll just glue it on here and I'm going to go have lunch when I come back it'll be stuck on there well enough we can machine the other side of it and here's the finished product he's just soak it in acetone overnight and it dissolves the glue and then the part Falls right off now we can make the fuel jet I just made this guy from a piece of 1/8 inch hex brass that I had and of course I didn't have the right size drill bit so I had to file one up

real quick that drill is about 16,000 of an inch in diameter that's about the thickness of four or five pieces of paper or about half of a credit card thick here's the fuel jet finished well hey if you like my videos consider supporting me on patreon patrons get access to adree videos and a patron only Discord anyway there's a link in the description next up we can make the needle valve this will control the amount of fuel going into the engine this fine point will fit into the fuel jet and by screwing it in or

out it will vary how much fuel can flow through the jet here it is finished it's hard to get a good shot of just how fine that needle is we're just about done now there's only two parts left just a propeller driver and the nut to hold the propeller on [Music] here they are after anodizing I'm not sure why but I couldn't get these to take anodize very well there must be some funny alloy we've got all the parts made now so it's time for best part we get to put it together [Music] the wrist

pin is a press fit in one side of the piston this is so it doesn't slide out and get into the ports I use my jeweling press to set it to just the right [Music] depth a good help in of oil is always important when you're putting these things together [Music] [Music] the connecting rod just barely has enough room to sneak in and get onto the crank [Music] pin the Piston is a very slight interference fit with the cylinder this way it can run itself in to just a perfect fit f [Music] the compression adjuster

screw is just a simple turned part with a cross pin in it in it with some Loctite [Music] [Music] [Music] [Music] I up a small spring to put on the needle valve this is so it doesn't move around the engine's running [Music] [Music] well it's all together there it is little tiny model airplane engine [Music] well let's take them outside and put them on the test stand see if we'll [Music] [Music] run the fuel mixture and using is 37% ether 25% castor oil and the balance kerosene unfortunately I didn't really have any success with this

fuel while I was trying to run it it was about 90° fhe outside and I think what was happening is as soon as the fuel touches the fuel tank all of The Ether boils out now on these small compression ignition engines The Ether is extremely critical to get it to run so without having any Easter in the fuel it basically won't run what you're seeing here is the best I ever got it to [Music] run but don't click off the video just yet we're not done this is a glow plug and if you watch my

last video series you probably know where this is headed a glow plug is used with a methanol-based fuel and the element in there is an alloy of platinum and aridium the methanol and the fuel reacts with that element and it keeps it glowing screaming love a hot while the engine's running and that's how it ignites the fuel now this glow plug is way too big to fit in this engine there's no way it would ever run with this one so this is a Cox engine this is their smallest engine they ever made and what they

did to solve the glow plug size problem is they just made the whole cylinder head the glow plug you can see it's got the same element in there it's just a whole lot smaller well I've got a machine shop so I figure I could modify one of those to work on our engine I've got this one here that I modified for a different engine years ago and I figured rather than sacrifice a brand new one let's try this one out see how it works we still have to change a few things though so let's go

ahead and go do that oh and if you're wondering about those marks there the confounded wrench slipped when I was taking it apart so I guess we don't have to feel too bad about modifying it I'll just make this a press fit into the cylinder head this will pretty much just replace the counter piston we have to open up some clearance in the cylinder head so that the glow plug can fit through and here's the glow plug there really wasn't much to do cuz that one was already partially modified and here's a cylinder head I

polished up the top a little bit so you can't see the marks I was going to reany it but I think this actually kind of looks pretty cool I think I'll leave it like this the fuel we're going to use is 20% nitromethane about 25% castor oil and the balanced methanol the compression feels a little bit low but let's go give it a shot the compression seemed a little low so I increased it slightly [Music] [Music] well as it turns out that's all the better I ever got it the Run there's a few things that

I'm not too crazy about with the design of this engine the first of those and probably the most important is the way the carburetor is attached there just isn't enough surface area for the Loctite to hold on very well and any leakage here causes a significant loss in crank case compression with a subsequent loss of transfer efficiency the second is the transfer Port Arrangement they have a very roundabout path from the crank case up into the cylinder so I think I'm going to sit down and have a think about this engine and see what I

can come up with I've got a few ideas for how we can do this a little better and I think we can go a little bit smaller too so keep an eye open for that in a future video well I hope you enjoyed watching this video as much as I enjoyed making it make sure you subscribe so you don't miss any future videos but that's all for this one so I'll see you next [Music] time oh wow that's hot as