A V8 you can watch from the inside. Turn the handle on the front pulley and the crankshaft drives eight pistons through their rods, while two gears turn the camshaft at half speed. The cam lobes push sixteen lifters and pushrods, the rockers tip and the valves open and close, cylinder by cylinder, in the 1-8-4-3-6-5-7-2 firing order of a small-block. The barrels are cut open so you see the pistons, the crankcase is open underneath, and there are no valve covers, so every valve is in sight. Eight velocity stacks and a distributor finish it off. It stands on its own stand, and every part prints without supports.
Free for personal use under CC BY-NC 4.0: print it, remix it and share it with credit to Shapekit. Please don't sell the files or the prints.
Every part as you print it. Pick colours to see what your filament will look like.
Drag to rotate · scroll or pinch to zoom
Every STL is already placed the right way up. Download them all at once, or one by one.
Both cylinder banks at 90°, five main bulkheads, the camshaft tunnel and two rails for the lifters. Each barrel has a window on the outside so you can see its piston, and the crankcase is open between the bulkheads.
Holds the crankshaft in the block: one under each bulkhead, two M3 × 20 screws each.
Valve seats and guides, spring seats, holes for the pushrods, four pedestals for the rocker shaft, exhaust ports and spark plugs on the outside and intake spigots on the valley side. The same part fits both banks, turned round. Eight M3 × 20 screws hold it on.
The front main journal and the D-shaped snout that takes the timing gear and the pulley.
A web with its counterweight and a crank pin, which carries two rods. Its keys only go together one way, so the four pins end up at 0°, 90°, 270° and 180°.
The web behind pin 1, with the next main journal. One dot on the counterweight.
The web behind pin 2. Two dots; its key is turned 180°.
The web behind pin 3. Three dots; its key is turned 270°.
The last web, with the rear main journal and the snout for the flywheel. Four dots.
48 mm between centres. The big end slides onto a crank pin before the next web goes on.
Ø29.4 mm in a Ø30 mm bore, with two ring grooves and bosses for the wrist pin.
Ø4.8 mm: a snug push fit in the piston, free in the rod.
Sixteen lobes, one for each valve, on five journals. It slides into the block from the front and turns once for every two turns of the crankshaft.
32 teeth on the front of the camshaft. Its dot faces the dot on the crank gear.
16 teeth on the crankshaft snout: it drives the cam gear at half speed.
The front pulley, with the handle you turn the engine by.
The flywheel with its starter ring, on the back of the crankshaft.
Flat-bottomed tappet that rides on a cam lobe, with a cup for the pushrod.
Ø3 mm with round ends, from the lifter up through the head to the rocker.
1.5 : 1 rocker arm: the pushrod lifts one end and the pad on the other end opens the valve.
Ø10 mm head on a Ø3.4 mm stem, with a groove at the top for the retainer. It opens 2.2 mm.
A small washer with a slot: it slides sideways into the groove on the valve stem and holds the spring.
Ø5 mm, through the four pedestals and eight rockers of one head.
An intake trumpet. It slides over the spigot on the head.
For the looks: a distributor with eight towers, pushed onto the peg at the back of the block.
A base with two cradles. The engine sits on four pegs and lifts off when you want to show the inside.
For a 0.4 mm nozzle. Filament amounts are estimates for these settings.
Nothing needs supports. Print the camshaft standing on its back end with a brim, and the valves, pushrods and retainers in batches. Clean any elephant's foot off the pins, journals and keys so they slide.
Push a wrist pin through a piston and the small end of a rod, so it sits in the middle. Make eight.
Glue the first crank throw onto the nose. Slide the rod for cylinder 1 and then the one for cylinder 2 onto its pin, then glue crank web 1 (one dot) onto the pin's key. Carry on the same way: throw, two rods, web 2, throw, two rods, web 3, throw, two rods, web 4. The keys only fit one way, so the pins end up at the right angles.
Lay the block on its back. Lower the crankshaft in and guide each piston into its bore; the bores have a lead-in at the bottom. Put on the five main caps with two M3 × 20 each and check that the crankshaft turns freely.
Slide the camshaft into the tunnel from the front. Turn the crankshaft until the dot on the crank gear points up, push the gear onto the snout, and fit the cam gear on the camshaft with its dot facing the first one. Then the pulley and, at the back, the flywheel.
Push a valve up through each seat, put a spring over the stem on top and press it down until you can slide a retainer into the groove. Drop the sixteen lifters into the rails in the valley.
Screw each head onto its bank with eight M3 × 20. Drop a pushrod through each hole until it sits in its lifter. Slide the rocker shaft through the pedestals, threading on the rockers so that each cup sits over its pushrod.
Push the velocity stacks onto their spigots and the distributor onto its peg, and set the engine on the stand. Turn the handle clockwise, as seen from the front, and watch the valves open in the firing order.
The engine has many small parts: keep them away from small children.
A 7-cylinder radial with a master rod, six link rods and a 34 cm propeller. Turn the crank and all seven pistons move.
View and download
A weight-driven wall clock with a one-minute tourbillon that is also its seconds hand.
View and download
Eight Theo Jansen legs and an N20 gear motor on two AA batteries. It walks across your desk by itself.
View and download
A working desk fan shaped like a car turbocharger, with a speed knob in the base.
View and download
A turbofan with 20 swept blades. Fits the Turbo Desk Fan's base and prints without supports.
View and download
A fluted planter for a 12 cm plant, with a hidden 0.6 litre reservoir and a float that shows the water level.
View and download
A sturdy headphone stand with a bayonet base, a cushioned hanger, an earbud tray and a cable hook.
View and download
Two small drawers and a wide one, with drawer stops and clip-on handles. Stack or link as many as you like.
View and download
Plug the back in at 55, 65 or 75 degrees. Fits phones and tablets in a case, with a slot for the charging cable.
View and download
A hanging seed feeder with a twist-lock tube, a perch ring and a roof that slides up to refill.
View and download
Pen cups, a scissor slot and a tray on a base that spins smoothly on 6 mm airsoft BBs.
View and download
A hand-cranked 5:1 planetary gearbox with herringbone teeth. Clicks together and prints without supports.
View and download
Lifts your screen about 12 cm at a 20° tilt. Fits 11 to 16 inch laptops; the cross bars wedge in, no screws.
View and download
Rolls any spool from 250 g to 3 kg on four 608 skate bearings, with a filament guide. Any hub size.
View and download
A 4 × 4 baseplate with eight stackable bins that fill it. Gridfinity-compatible, no supports.
View and download
Two baffles and an exit ramp tumble your dice into a tray with a felt recess. No glue, no supports.
View and download
Two AA chutes and one AAA chute. The bottom battery rolls onto a tray, the next drops down.
View and download
Two number cubes show every date, three bars show the month. With a stand that hides the spare bars.
View and download
Put your own photo in a phone case, lamp shade or lithophane, right in your browser.
Open the makers