Vacuum Engine ✦ Flame Licker/Eater Model ✦ HOME MADE

Here is the first hot air engine I tried to make.
With me being relatively new to a lathe, I was definatly throwing myself in the deep end with regards to machining tolerences.

Because vacuum engines are inherently temperamental at best, they are very difficult to make. Especially at the scale I tried to make mine. But after a lot of frustrated tinkering, I fatally got one going.

It has a solid bronze flywheel that runs on two degreased ball bearings.
It also has two smaller degreased bearings - one for the cam shaft roller, and the other for the piston con-rod connection to the eccentric.

The cylinder is made from aluminium, with a brass cylinder sleeve.
I found a cast iron sleeve worked great as well, but quickly corroded due to the hot gasses, causing the piston to seize in the cylinder.

The piston is micro grain graphite (polished will regular paper). Vacuum Engine pistons should never be lubricated with anything but a dry graphite powder, because anything else will create too much friction (a graphite piston shouldn't need any powder).

The cam shaft is brass and runs in a small cast iron bushing pressed into the aluminium cylinder. It also has a 1mm guide rod that runs in a 1.1mm hole drilled in the aluminium cylinder. This guide rod prevents the cam shaft from rotating and misaligning the bearing and valve with the cylinder and cam disk.

The valve is made from brass and runs against a flat ground SS plate that is screwed to the side of the aluminium cylinder. A small spring made from 0.1mm SS foil is used to gently hold the brass valve against the SS plate.

This engine also has a positive internal pressure release valve.
I used a brass seat and a ceramic bearing.