As with most of you I love all of Eric's models. Unfortunately I do not have a machine large enough to print any of them as they are designed to be printed. I have scaled all the parts down to 50% of the originals size and had to modify many of them to make them print better at this scale. I also replaced the hardware with more commonly available items since at this scale the actual hardware (1.5mm diameter bolts) would be hard to get and costly.
At 50% size it is only 1/8 the volume so it prints in about 20-40 hours unlike the 200 hours for the original. But this time savings is at the cost of time to assemble going up. It has taken me about 40 hours to assemble, redesign, make hardware and reassemble the engine not including the actual print time. It should be possible to assemble in a couple of nights.
All parts fit within a 100mm x 100mm x 100mm build area.
All bearings have been replaced with bushings (sections of grey Polybutylene sink riser 9.5mmO.D x 6.2mmI.D.).
All bolts have been replaced by 1.5mm brad nails or 2mm copper wire and CA glue.
The timing belt is an O-ring.
The push rods are currently made from paperclips.
The rocker bolts are the tops of 18g brad nails for a nail gun.
The cam shaft is now three parts printed vertically (requires support).
The crankshaft has had all bearing surfaces resized for the plastic bushings. Also the numbers have been increased in size and the clocking marks have been made into indents.
Crankshaft output flange has had the lip made a little thicker.
Crankshaft rear spacer has been merged into Crankshaft 8.
Engine block main bearing surfaces have been resized for the plastic bushings.
Exhaust and Intake Valve have had their holes resized to fit the 2mm copper wire valve stems.
The flywheel has had the clutch bolt holes moved in from the edge for printing reasons.
Main bearing caps bearing surfaces have been resized to fit the plastic bushings.
The rocker arms have been widened and have had the support redesigned to make removal easier.
The spring retainers have been redesigned for push fit over the 2mm copper wire valve stems.
The starter gear has been remodelled for push fit onto a small motor.
Both valve covers have been thickened along one edge to improve printing.
The printed rocker arm pins have been replaced with a piece of 2.85mm PLA filament with a small hole drilled through the side for the rocker bolt (18g brad nail).
Please see the pictures for a better understanding of the hardware used.
I do not have it working 100% at this time. When you turn the flywheel it does lift the lifters and the pistons go up and down. But the springs I made for the valves are a little to stiff for the cam to open the valves. I also do not have magnets for assembly yet, in place of the magnets I may use pins if I get impatient.
This is an advanced project for detail oriented people with well tuned printers and lots of patience.
UPDATE: Jan 31, 2017
Added exhaust headers (See notes below)
Added a stand to hold engine for display. It cradles the oil pan and slot together without any hardware. (could be scaled up for use with the original).
UPDATE: Feb 20, 2017
Added missing Cam Gear
The large parts can be printed at .25 but the small part should be .15
Some of the parts will require support and some may benefit from the use of rafts. Please see my notes above and see Eric's original instructions/pdf's.
The Exhaust Headers are very thinwalled and may not slice correctly so please go through your layers after slicing. You may need to set your extrusion width lower than 0.4 to get a good print.
I've included the Blend file but most of the work was done via mesh manipulation so its not much use to anyone else except it does use booleans to enlarge the bearing surfaces in the block and bearing caps.