Hello, Have another project in the works: a forty inch open steam launch. Sourced the hull and engine locally in Ohio. PMResearch #8 engine and Ministeam launch.
Built the engine last night. I bought the machined kit. Very nicely machined and made. Heavy bronze base casting. All parts brass, copper, or bronze except spring washers and shafts which appear to be stainless. I did change the piston nuts from brass to stainless steel. Took about two hours to assemble. I polished the oscillating mating surfaces to 600grt on a small piece of plate glass. You will have to make a press guide (see pic, top center pin and base device) to press in the 2 3/16 bronze bearings.
Then you will need a 3/16th undersized reamer to finish out the bearings internally as they compress a bit when pressed into the engine base. You may also have to ream out the pivot pin bearings with 3/16th undersized reamer. A bit of filing and cleaning (including the crank shaft machined ends) and she goes together very well. Adjusting the piston rod length to find the sweet spot was a matter of a few turns of the rod and locking the rod nut. Split teflon piston rings X2 per side fit on easily. O rings for the glands work well. Size is about 4x3x4. Hardest part is cutting out the four paper cylinder gaskets. I have a hole punch which definitely saved time and made for nice round holes.Ran great right after assembly at low psi in both directions.
You will not need many tools, but you do need:
good small regular screw driver
600 grt paper
small allen wrench
3/16th undersized reamer
bearing guide for press (shaft should be 6-8 thou under 3/16th diameter to allow for compression of bearing)
#3 wrench
pliers
locktite
sharp knife
https://www.youtube.com/watch?v=diwGIN3AWtc&feature=youtu.beIn the end, you will be satisfied with this engine. Runs well and builds easily. I chose this engine and hull so that I could focus on the boiler build in this launch. I try to really learn how to build at least one or two main aspects of each of my models. It can become cumbersome at times to make all the parts (engine , hull, boiler, design, etc) for all of my builds. So I try to focus on an aspect of each build more seriously to improve and challenge my skills.
Plan for boiler: scratch built 3 inch dia vertical gas fired copper