This is a remix of the brilliant Deltic engine made by Zefram, which I’ve enjoyed making twice now. This remix is to fix a few of things I was not happy with – the ease of turning the engine over, the size, and the need for supports in many of the components.

It has been scaled to 60% of the original. The base is sized for 608 bearings to be pushed into the base. These are the standard skateboard / fidget spinner bearings available on Amazon for pennies. I pushed the bearing in with a vise – very easy. The driveshaft protrudes from the underside of the base, so that it props up on a desk, and this can be used to turn the gears either by hand or in the chuck of a hand drill. The original required much print support for the liners and the conrods, and I really hate supports. I’ve made this so that liner, pegs (that mount the liners) and the single main bearing conrod can be printed with no support, but they will need dabs of CA and possibly accelerant to assemble. The dual main bearing conrod can be printed in two halfs and glued together. You still need to run a drill through the main bearing hold so that it runs smoothly. The gudeon pins (that hold the piston to the conrod) is made from unused 1.75mm filament, inserted then the ends melted with solering iron. I then removed the excess melt with a craft knife. I have removed the index points from the gears. Once assembled it’s easy enough to rotate the cranks against the gears until the correct position is reach, then put a drop of CA to secure it. The original was odd in that all the liners where marked and had to go in certain locations, but they were identical as far as I could tell?

Original Sketchup file is included, with parts labeled. Refer to the original instructions (by Zefram) for print quantities etc.

All credit to the original by Zefram, I hope this remix inspires some fresh builds