this instructable will show you how to make a car with a crankshaft and two pistons. if you do not have pieces that I do improvise and if you see a better way to do things, feel free to make adjustments.
Step 1: Materials
1x flat 6x16 piece,
1x flat 6x10 piece,
1x flat 6x2 piece,
1x tall 6 piece,
2x tall 4 pieces,
2x tall 8 pieces with holes,
2x tall 10 pieces with holes,
2x tall 12 pieces with hole,
2x tall 2 pieces with crossbar hole,
3x tall 4 pieces with holes,
3x tall 2 pieces with hole,
8x tall 6 pieces with holes,
12x tall 2 pieces (regular)
1x driveshaft u joint,
1x propeller/fan (optional)
4x T crossbar pieces,
6x long crossbar wheel stopper,
2x short crossbar wheel stopper,
2x long crossbar,
4x kinda short cross bar,
2x shorter crossbar,
3x shortest crossbar,
4x 2 level crossbar stopper,
2x low friction pin,
4x low friction pin cutoff
1x medium gear,
1x medium gear w/ bent teeth,
2x wheel with holes and no tire,
2x front wheel,
2x rear wheel,
2x tall 1 space wide slanted piece (needed in making track for other piston (continued))
Step 2: Make Crankshaft
use 2 level crossbar stoppers and shortest crossbar and T crossbar pieces to make the crank. on the rod use shorter crossbars to connect the 2 T pieces and I think you can see the rest.
Step 3: Make Crankcase.
use tall 6 pieces to set the crank in. for base use the flat 6x16 piece. leave 2 places in front for "radiator" thing
Step 4: Put in Cooling Fan
put cooling fan on front of "engine"
Step 5: Making Fan Cover
build up 3 tall 2 pieces on each side of the cooling fan and put the flat 2x6 on top
Step 6: Making Track for "piston"
stack 1 of the tall 2 pieces with the hole in it on each side of the "piston" (make sure you put these on the back of your engine)
Step 7: Making Track for Other Piston
on top of the "radiator" box put 2 tall 2 pieces 2 spaces apart
Step 8: Making Track for Other Piston (continued
put the slanted pieces on the tall 12 pieces and then put then slanted piece toward the front onto the top. put two tall 2 pieces on to of that one space from the end so when you turn the crossbar from the crank the "pistons" will smoothly go up and down along their track.
Step 9: Putting on U Joint Driveshaft
that seems pretty self explanatory put it on the opposite end that the fan is
Step 10: Put Wheel Base On
use the tall 8 piece to put the other flat base on the back
Step 11: Adding to Rear Wheel Base
add 1 tall 6 piece with holes on either side of base and then a tall 4 piece with hole on the end.
Step 12: Making Rear Whells Work for Me (depends on Wheels)
put 3 cut off low friction pins on opposite sides of wheels with hole and insert the onto the other wheels. I did this because my crossbar for rear wheels was not long enough.
Step 13: Drive Shaft Support and Putting It In
the first picture looks pretty self explanatory. put the drive shaft through the 2 hole piece and the push the piece in one line away from end
Step 14: Making "differental"
put the gear with bent teeth on the end of the drive shaft. ( you will adjust it later)
Step 15: Put Rear Axle in One Rear Wheel
again that is pretty self explanatory
Step 16: Finish Driveshaft
put shaft you just made through the back piece and put the other gear on that and the other wheel on the other side and adjust gears as needed
Step 17: Your Done
I added a body and stuff just to look cool but do what you like