Introduction: Big Mechanical K'nex Car

Welcome all to my entry for the K'nex Instructables contest! My creation is a big vehicle with realistic mechanical features, and a bunch of extra interesting components!

I started playing with K'nex when I was around 3-4 years old and have always loved it. I would make things very often with it at younger ages, but have continued to go back every now and then to build while in my teens, and even sometimes now in my 20's. It has also came in very handy for some school projects while I was taking a mechanical technology course (and was a great inspiration for my enrollment).

I had wanted to build this since I had last used my K'nex about 18 months prior to this build, which was for a smaller and more flimsy version of a car. It still had most of the main components in it, but was still quite inferior to this new model. I had actually started building the beginning of this project before I knew about this competition, but once I realized it was taking place I told myself I definitely wanted to be part of it!

NOTE: Only the first 2 images on this first page are of the new car, the others are what I had of the old car (which is now completely dismantled). Please check out later 'steps' for more details on the new one, and open the pictures to see a bunch of extra good info and comments on both builds!

Unfortunately despite my best efforts, and probably around 150+hours of work so far, I was unable to finish everything I wanted to do for this project, however I'm still very proud of what I have so far and still consider it worthy of contesting as is. =]

Please understand though that with a project of this magnitude it is somewhat impractical to make a complete guide to building it, however I will do my best to detail the most important aspects through a mix of pictures, videos, and text!

Also please watch the video a close cousin of mine helped me to make. It will likely be much more clear to understand any moving parts. I forgot to detail a few things in it, but anything I missed I'll be sure to discuss in here.



Step 1: Build Progression/Details

What features this car has:

  • complete individual suspension
  • front wheel steering
  • rear wheel drive
  • dual universal joints per rear wheel to transmit drive through suspension
  • rear mounted V8 engine with moving pistons, connected to drive train
  • differential with very little friction
  • engine may unlatch and pivot open to put car in neutral and reveal hidden differential
  • doors with automatic slip-in latch with opening handle on exterior
  • adjustable steering wheel height
  • secondary steering lever just inside hood to be pulled/steered by chord
  • automatic locking hood with button in front to unlock
  • hood soft clicks up at top to stay open without a bar
  • seats that can be adjusted front to back on slider
  • seats have a ratchet mechanism requiring a lever to be lifted to recline
  • seats have custom upholstering
  • very well reinforced handle just under the front bumper to make it easy to pick up
  • wheels have custom made rims and tires
  • the wheels are also on steel shafts and ballbearings to support the very heavy weight of the car
  • custom wired LED headlights with 8xAA battery pack under hood and switch placed next to steering wheel, also light angle may be slightly adjusted in and out

A few main things this car has that the old one didn't, and other differences between them

  • old: rear wheel drive, front mounted V6 with straight pieces moving in and out as pistons - new: rear wheel drive, rear mounted V8 with an actual flywheel per piston
  • old: much more friction in drive train
  • old: probably around 2.5'/76cm long - new: 4'/122cm long by 2'/61cm wide
  • old: nowhere near as heavy - new: approximately 40+lbs or 18+kg
  • old: way less pieces - new: estimated at around 10,000 pieces
  • old: no seat mobility, no door latch, no lights, no secondary steering mech
  • old: had window wipers made with mini K'nex - new: window wipers yet to be installed

Plans for the future of this car:

  • will make finishing touches to small incomplete sections, and will fortify some important moving parts
  • I have a piece of plexiglass that I will cut to make front and back windsheilds
  • will make window wipers
  • rebuild the engine to be a bit bigger and look nicer
  • might add more lights
  • will add body covering with plastic sheets and then spray paint them a metallic 'dark steel' color
  • once satisfied with all that and maybe a few other things I will make and upload a new video to youtube

Step 2: Custom Wheels and Seats


  • 2 large K'nex gears were glued together, but only using the spokes from one, this gave me more surface area to attach the rim
  • Plastic sheeting was used for the wheel rim, 3 layers glued one after another to ensure wheel stability
  • holes were drilled through the layers after and a tiny amount into the gear teeth to allow more glue to set through all the layers
  • 'Diamond-plate' EVA-foam floor mats were then glued on as the tires
  • Lots of hot glue was used


  • After a frame was made with the reclining mechanism, I covered the outside corners carefully with foam pipe-insulators
  • I then put some EVA-foam shelf-liner on the bottom and back for extra cushion and stability
  • That then was entirely covered by an adhesive-backed plush felt

Step 3:

K'NEX Contest

First Prize in the
K'NEX Contest

Move It

Participated in the
Move It