3D Printed Engine Model

My name is Jay-Anthony Munoz, I love building and creating things. When I first got into 3D Modelling I came across a video by Adam Savage titled "Working 3D-Printed Car Engine Models!" where he interviewed ericthepoolboy at a Maker Faire. Immediately I was hooked on the idea of 3D printing a fully-functional scale model of an engine. This is a very important project to me since one of my biggest hobbies besides 3D printing is cars. Ever since I was little, cars have always fascinated me, especially engines. I hope to use this model to learn more about the mechanical aspects of cars, as well as to teach others. Because of the resources in Ms. Berbawy's Principal of Engineering class this project became a possibility.

Things you will need are:

3D Printer

Computer

Allen keys or a Allen driver kit

Dremel

a Drill

Super Glue

MakerRX Hardware

Soldering tools

Dial Calipers

And lastly a lot of time

A big part of this project is 3D printing, so understanding how a 3D printer works is quite important. During my experience I was able to assemble a Prusa i3 MK3S+ and fully understand the ins and outs of the printer. If you already have a 3D printer of your own, make sure that the build plate is big enough to print the needed parts (preferably larger than 7 inches by 7 inches to comfortable fit the engine block). If the build plate is not large enough simply split the STL file into several pieces to accommodate to the printer size. Some things to note are the main engine block takes a couple of days to print, and some of your prints may fail due to printer error. All the files for this engine are available on Thingiverse thanks to the designer, ericthepoolboy

I downloaded all of the STL files onto my computer and sliced them. A slicer is a program that allows the user to turn a 3D model into instructions for a 3D printer to print that model. Since I was using a Prusa MK3S 3D printer, I installed and used Prusa Slicer. The printing adjustments I made were to add supports and a raft to the build plate. Supports allow the printer to print aggressive overhangs without altering the part file. A list of these STL files that need supports are as follows...

Cylinder Head

Timing Cover

Rear Cover

Bearing Cap 1

Bearing Cap 2

Valve Cover Passenger

Valve Cover Driver

Engine block

Oil Pan

Intake Manifold

Headers (left and right)

Rocker Arms

This is a long list but adding supports is easy, although removing them is sometimes challenging. Above are two pictures taken inside of the Prusa Slicer before and after supports. As you can see the Engine block with supports takes almost four days to print, so save up ahead of time for your electric bills.

When every part was completely printed, I removed the supports and sanded down the bumps . Then, since I had not altered the STL file, I drilled out the places for the the magnets and bearings. I used magnets to give the illusion that the parts are all bolted together. I attached the magnets with super glue (picture 1). The magnets need to fit snugly. At this point I also inserted the provided threads into the corresponding holes.

The second and third pictures show a complication I had with my printer, in which the build plate shifted so my prints were offset to the right during a print. This made it more difficult to put in the magnets necessary to hold the cylinder heads.

The file is a diagram showing where the magnets, screws, and threads go.

An important detail I learned during this step is that measuring the lengths of these parts is very important. During my process I had to dissemble and resemble the camshaft because I didn't sand off the rafts completely. Without a well assembled camshaft and crankshaft the project won't be able to get the "gears turning/functional model" look that makes this model 1000% better. Above are the measurements taken from the instructions provided with the part files. After fully assembling both shafts I added them to the main block. The camshaft was inserted through the hole that extrudes through the engine block. The Crankshaft was secured by the main bearing caps on the bottom of the block. Below is the order in which each shaft should be assembled.

Camshaft Order

3M Threaded Rod, Cam Bearing Surface 3, 6702zz bearing, Cam Bearing Surface 1, Cam Lobe 16, Cam Lobe 15, Cam Lobe 14, Cam Lobe 13, Cam Bearing Surface 3, 6702zz bearing, Cam Bearing Surface 1, Cam Lobe 12, Cam Lobe 11, Cam Lobe 10, Cam Lobe 9, Cam Bearing Surface 3, 6702zz bearing, Cam Bearing Surface 1,Cam Lobe 8, Cam Lobe 7, Cam Lobe 6, Cam Lobe 5, Cam Bearing Surface 3, 6702zz bearing, Cam Bearing Surface 1, Cam Lobe 4,Cam Lobe 3, Cam Lobe 2, Cam Lobe 1, Cam Bearing Surface 3, 6702zz bearing, Cam Bearing Surface 1, & a Cam Gear.

For the Camshafts after every four lobes I added one bearing.

Crankshaft Order

M3 20mm SHCS, Crank Gear, 6701zz Bearing, Crankshaft 1, 6701zz Bearing, Crankshaft Spacer, 6701zz Bearing, Crankshaft 2, M3 25mm SHCS, 6701zz Bearing, Crank shaft 3, M3 18 SHCS, 6701zz Bearing, Crankshaft Spacer, 6701zz Bearing, Crankshaft 4, M3 25mm SHCS, 6701zz Bearing, Crankshaft 5, M3 18mm SHCS, 6701zz Bearing, Crankshaft Spacer, 6701zz Bearing, Crankshaft 6, M3 25 SHCS, 6701zz Bearing, Crankshaft 7, M3 18mm SHCS, 6701zz Bearing, Crankshaft Spacer, 6701zz Bearing, Crankshaft 8, 6701zz Bearing, Rear Main Spacer, Crankshaft Output Flange, & M3 25mm SHCS.

The Piston assembly is Attached above and the parts needed for one piston are as follows. The Piston, a Connecting Rod Bearing Cap, Connecting Rod, M3 25mm SHCS, m3 nut, & two m3 16mm SHCS. At the end of the assembly I ended up with 8 Pistons for each of the Cylinders, hence the "8" in "V8." One Piston will attach to one of the 6701zz Bearings we put on the Crankshaft. Pertaining to the Camshaft I assembled in the previous steps, I attached the flywheel to the end of the Cam Gear. When these steps are completed I secured the timing chain to the end of the Crankshaft Output Flange and the Cam Gear. Now, at last, I was able to see the pistons shift up and down when the flywheel is in rotation.

Next I assembled the lifter assemblies so I prepared the lifter and steel ball and secured them both with super glue. I also assembled the intake and exhaust valves with super glue. When these steps were finished I attached them into the main block along with the Cylinder head. Then I attached the rocker arms and rocker rail to sit on top of the prepared valves. Above are the diagrams provided by the designer...

When all of the assembling was completed, I drilled holes in my oil pan where I thought the proper place would be. These holes were for the DC Female Power Jacks, for the power supply, and motor. After I secured the DC Female Power Jacks, I soldered the wires together, I also put the electronics into the oil pan so they could be connected on to the starter. I wanted to make sure to secure the wires to reduce the chance of them getting damaged. Lastly I attached the starter and its mount to the engine block, making sure the starters' teeth align with the fly wheel. At this point I plugged it in and watched the magic unfold, above is the video of the my project functioning.

I am very happy with how my project came out, but I am not done with it. As most car enthusiast know, a car can always be modified. So, in the future, I will add things such as a supercharger, LEDs that will indicate combustion in each cylinder, or even a small speaker for the engine sounds. Like project cars, projects like these can always be improved and upgraded. So have fun with your creation and learn more about cars. Thank you for checking out my project, big thank you to ericthepoolboy, Ms. Berbawy, Prusa, and to MakerRx for allowing me to build this model.