10/21/2025 - Researching engines

Since I’m 99% sure that a fully CNC’ed V8 + transmission system would be out of the budget, I’m going to create an 3D printed, motor powered alternative.

The plan is that it will mechanically behave the same, but instead of running on gas, it will run on a small motor powered by a dev board of some sort.

I need to learn more about engines and their internals for me to actually understand them before making a 3D model of one. I’m going to divide the project into 2 sections, the engine and the transmission. I will be starting with the engine first.

Here are some videos I plan on watching:

• https://youtu.be/ZQvfHyfgBtA
• https://youtu.be/KZLygdpg3LU
• https://youtu.be/9KKfIYch1FE
• https://youtu.be/PXDFuIMHNZw

10/22/2025 - Basic research + Engine selection

For my crankshaft, I'm going to go ahead with a flat-plane. Since designing flat-plane is going to be way easier to 3d model compared to a cross-plane(designing a flat crankshaft compared to one with multiple 90 degree angles), has lower fiction, and less need for supports. I decided that this will be my first project. I may do a cross-plane engine in the future once I'm more advanced in 3D modelling.

Because I want to be able to see the pistons in action as well, I'm most likely going to get rid of the cylinder head's or have openings in them so it'll still resemble a full engine, but still have viewing spots for the pistons.

This entire model will most likely be held together by screws, alignment pins, and maybe some type of adhesive(for non moving parts).

I'm not sure about using plastic bearings yet, since they may just quickly wear down so I might just use real metal bearings instead.

I would also prefer the engine to be under 12in x 12in x 12in, but I'm not sure about the transmission yet.

https://www.youtube.com/watch?v=wCu9W9xNwtI

11/10/2025 - Created piston

Started the project and finished making the piston. Next I'm going to create the crankshaft and then add the pistons on each side. I'm not going to create any joints so far, I decided I'll create them at the end of each stage

11/11/2025 12 PM - Created crankshaft

Created the main part of the crankshaft, now it's time to mirror and pattern it

Mirrored and added a fillet (used the same fillet used on the piston)

Patterned it and added a flywheel

11/11/2025 3 PM - Added pistons

Made the flywheel look a little better and added set screws to attach it to the crankshaft

Added each of the pistons now at a 45° angle but theres still some imbalances which I need to fix

11/12/2025 - Created joints

I created joints for all the pistons and crankshaft so now I'll be able to see the engine in action

I spent a lot of time doing this because I had to restart multiple times (mainly from my lack of experience with joints) since I kept on getting errors or my joints just stopped working

11/16/2025 - Pistons fully completed

Little Update

• Fixed the spacing between the pistons
• Fixed the piston alignments so each piston is on one row instead of 2
• Next step will be to figure out how to design the clutch system and how I could properly connect a transmission to this.

Future

I plan on having this entire system mounted on a control panel with a tachometer (If I'm able to get one working), an RPM control knob, start/stop button, and a display for other metrics.

11/21/2025 - In process of creating engine block

This is one of the most time consuming parts of the entire project so far. Right now I've been trying to build the main shape of the block before I add the finer details and groovings later.

I've been trying to create the block based off of google images and how other people did it with their 3d models.

11/22/2025 - Almost done engine block

Made the flywheel a bit bigger and more realistic looking

Created the crankshaft support bracket

Added the mounting holes for the cylinder heads in the future

11/28/2025 - Created motor mount

Created the motor mount and gear that'll drive the entire engine. For the motor I chose the basic RS-775 since it's popular and has many different uses.

11/30/2025 - Dropped the transmission idea

After some research and consideration, I decided I'm not going to create a transmission for my project. As I'm still relatively new to 3D designing, creating my own transmission and gear setup would take a very long time due to it's complexity and knowledge required, which I can't learn and finish before blueprint ends.

Updates:

12/5/2025 - Created the base

Created the base which will hold the engine and decided to go with a 1602 control panel, a knob to adjust RPM, and a stop/start button. Since the base is going to be pretty big I'm going to split it into 2 parts in the end for easier printing.

12/7/2025 3 PM - Found parts and started schematic

Because I want to keep this project simple, and that I have no use for the LCD other than displaying the RPM (which won't go very high anyways or else the engine will melt itself) I decided to remove the display entirely, which also means I won't need a SoC for my board.

I took a little break after and started my shopping list, I needed:

• The motor (I chose a basic 775 for this project)
• Heat shrink (for the soldered the wires on the motor)
• Lubricant for my moving parts
• Wires for the motor
• Power supply

Since I couldn't find any cheap 12v batteries on aliexpress (mainly due to shipping costs). I tried amazon and found this 12v battery which was cheaper than all the other batteries I've seen so far and it included a charger too!

Now back to the schematic

Created a PWM speed controller for the motor

Created the start and stop buttons using an SR Latch with transistors

12/7/2025 5 PM - Updated CAD

Made the stop, start buttons and the speed knob look better

I also may need to either switch my power supply or switch the type of motor I'm using since the 775 can spike current up to 10-50amps, which will ruin my battery, so I need to find a solution to that too.

I'm going to be adding some more tolerances to the CAD while I wait for my schematic to be reviewed by others.

12/8/2025 6 PM - Started PCB

Schematic updates

• I forgot to change the reset pin's connection from 12v to the 555's VCC pin so that it's always turned on when I created the on/off controls, which is fixed now
• I cleaned up and organised the schematic a bit and added mounting holes.

Started PCB

For this project I want to hand solder everything onto the PCB, so I'm going to be choosing mainly THT and some SMD parts for my board

Keeping my CAD design in mind, I'll probably have the motor connectors on one side, and the button and potentiometer connectors on the other, with the power connector being at the top or bottom.

12/8/2025 9 PM - PCB Adjustments

After finishing up routing and component placement of the PCB, I realized that using mainly THT components really crowd up the board and it'll be a challenge to fit it in my enclosure, so I'm going to switch to SMD components.

12/13/2025 3 PM - Replaced pinheaders with pads

Instead of pinheaders, I decided to just add pads to directly solder the wires on to save space, money, and to be more permanent. I also added silkscreen for each pad for better clarity when soldering

I also started the BOM for my project, and I need to clean up some other parts of my PCB and I should be almost finished

12/13/2025 4 PM - Finished PCB

I switched out the THT decoupling capacitors and the diodes to their SMD alternatives to save space and to keep stuff simpler.

Rerouted components to make it cleaner and more silkscreen, waiting on final review now.

12/13/2025 5 PM - Started adding components to CAD

I added the potentiometer and the buttons to my base, now I need to find a way I can mount the components in then add the tunnels where I can route all the wiring.

12/13/2025 9 PM - Updated PCB + CAD

I decided that I'll go with creating modules for each button. After I assemble each module I can just push them into the base and wire them up to the controller

Started wire management

Here I realized my PCB's height would be way too big to fit inside, so I had to make some more adjustments to my pcb. I also need to reorder the pads so that it aligns with my components.

I got to reordering the pads, but I couldn't really find any smaller replacements for those big components, so my workaround is to bend the transistor and diodes a little to make everything fit

12/14/2025 5 PM - Updated motor + gear system

Added vents to help cooling the PCB

I plan on my engine running at about 1000rpm max. I tried finding a 12v brushless dc motor or a planetary gear motor but couldn't find any under $30, so I went with a 4000rpm motor and then added a third gear to create more torque and to lower the speed.

The output gear is going to be mounted with a 608 bearing and a M8 screw directly to the engine block

I'm gonna add a few more details to make the engine look a bit better and realistic looking

12/14/2025 9 PM - Fixed tolerances + Updated screws

Cleaning up CAD

• Added tolerances with the control panel modules so it's easier to assemble
• Instead of using screws to attach the crankshaft support bracket to the engine block, I used dowel joints with chamfered edges
• Updated the connecting rod cap holes so they fit a proper screw
• Added a coupler to attach the motor to the input gear
• Created the bottom cover
• Made LED less visible

12/24/2025 9 AM - Final CAD Fixes + Onboard LED

I fixed a ton of small issues with the CAD over the last week so it'll be easier for me to just show my completed to-do list.

For my PCB I decided to add an onboard LED and this is where I realized all my resistor footprints were set to capacitor footprints, after which I updated them and then added the onboard led.

The PCB has been sent to get reviewed. After thats completed I'll move onto working on the BOM and readme files.

12/24/2025 7 PM - PCB Updates

After some help I fixed my on/off buttons and my pwm controller. I also discovered falstad which helped me greatly in debugging and testing my circuits.

Added reverse polarity protection

Updated schematic and rerouted the PCB

1/18/2026 - Soldered SMD components

Starting from smallest to biggest (0402 components to 1206 components) I soldered each part one by one. I put a little blob of solder on each pad, then I placed my component on it, then I heated the pad with my iron. But because my iron tip is way bigger than the 0402 components, using this method was way more challenging and time consuming for me.

Soldering R7 here

Repeating this method I was able to solder all the 0402, 0603, and the 1206 components. At first it took me about 5-15 minutes per 0402 component because of how tiny they were and easy to misorient, but after a few resistors successfully soldered I was able to get the hang of it and solder each component in less than a minute.

I went back to fix R8 but unfortunately my wick got stuck on the component and after getting it off, it ripped off the pads too.

Since I have 4 other pcbs I just decided to desolder everything and move them there. I tried soldering on R8 onto my new PCB, but it didn't stick at all no matter what I tried to do. I then tried to move R10 onto the new board, and accidentally pulled the pad off too.

So now I'm on my third board, I'm being extra careful this time and I lowered my iron temp from 325C to 300C.

Since my R8 and R10 resistors didn't stick to the pads anymore I just replaced them with new ones.

After my third attempt I was finally able to transfer all the old components on to my new PCB. After that I was able to solder on my diodes and transistors easily, finishing all my surface mount components

In this process however, I didn't realize you could easily damage or melt surface mount LED's with a lot of heat, so I ended up destroying my LED trying to desolder it. My plan now is to just use a regular 5mm THT led and soldering the pins onto the pad as a makeshift onboard LED.

1/20/2026 - Soldered THT components

Soldering all the through hole components was way easier than the SMD components and only took me about an hour

The vertical height of the PCB was way more than what I expected though, after I test the pcb to make sure everything works I'm going to double check if it can fit in my engine enclosure

1/24/2026 - PCB issues

Since I don't have a replacement SMD LED, I resorted to soldering two wires onto the pads to connect an external LED to serve as my new onboard led.

I put small pieces of electrical tape between the pads to cover up the exposed wire and to try and prevent any short circuits

Now the onboard led replacement works perfectly fine when I power up my board, but when I tried testing the on led along with the on/off buttons, the led wasnt turning on at all. Since I don't have a multimeter theres not much I can do to diagnose the issue until I can get one.