A Miniature Triple-Expansion Marine Engine Model


Wednesday, 19 March 2008

Going a little bit further

This is the first post of 2008 and there are some updates in the treatment of our miniature marine engine. The dilution of old lubricants and accretions during nearly four months in a solvent bath was impressive.
Frequent changes of the solvent were required to keep the dilution process flowing. In the very first seconds of the new video you will be able to watch the amount of accretions that have been captured by the paper filter in the bottom of the bath. However, the solvent itself is not enough for deep cleaning. Mechanical cleaning using a variety of soft brushes is required to remove accretions that come in the form of thin film which is thick enough in this tiny engine to obstruct the moving parts!

On the other hand, in each cleaning session we try to release the moving parts, one step at a time. Despite that the pistons are working properly, it is still difficult to give a full turn to the flywheel. We are carefully inspecting the operation under the microscope in order to detect the cause of this malfunction however we still need a lot of work in removing every accretion from the interior, in order to be certain.
Finally, we tried to apply some air flow in order to check the condition of the valves. The good new is that the air can go through. Unfortunately, the gap between pistons and cylinders is too large, resulting in "blow by" or air-leakage (last part of the video). In other words, the cylinders cannot hold enough air pressure to drive the pistons.
We are currently examining a new method that can speed up the cleaning process. A successful treatment requires careful preparation, great patience, and most of all no assumptions or speculations. Stay in touch till the next update!