Hello There! This design was such a blast! Thank You to @Markerworld for making this possible and giving me supplies and helping me on this project I wouldn’t have been able to do without them.

I faced many challenges in this design but I loved every bit of it the challenges and the process. That’s what makes 3D printing so fun even though there are hiccups that just makes you push farther and gives you even more ideas like a hiccup gave me the idea to add a real spark plug. It just adds even more fun and that why I love doing stuff like this and Makerworld platform is the best for it. Here is the versions I did. 

👇 Floats
V1: I made a simple not very detailed spark plug I originally wanted to just do a spark plug but realized it was going to be to hard and impossible to put the float base inside a spark plug and make it float so I got a splendid idea put a base over the main base that held a spark plug upright when I had this idea I originally did not think about how the lights would light it up but when it lit it up I amazed and realized this route would be the best route.

V2: Now that I knew that my design and its lights from previous V1 worked I decided it was time to do the more detailed version with a few updates I made where a more realistic sparkplug added a less shallow base so it didn’t stick below the main base float. I also switched dovetail connection points to a dowel. I ran into one issue though the spark plug wasn’t strong enough at the bottom. 
 

V3: I added reinforcement to the bottom and added a pin/dowel to the bottom to hold in place instead of just glue. 
V4: I also got the idea just now that I could make a real spark plug float. I added even more reinforcement and it proved strong enough.

Real Spark Plug 
V1: I added a hole to my finished base float. It worked the hole was just a bit small because of the layer spreading and filling in the hole on layer one. 
V2: Added a bigger hole it worked.

Main Base
V1: I designed a simple piston. It didn’t  the most realistic though and somewhere I messed up on measurements so it was way too big and would not work. (Left one in filament graveyard pic.)

V2: I studied the best way to make a realistic piston without showing all the  piston head with minimal supports. I made it as small as possible and it worked and looked amazing.

Finished Product 

Filament Graveyard: 

Click here for the model. 👇