Engines > Restoration of Model Engines

An old overcrank engine

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Sanjay F:
This is a very old and dusty overcrank engine; it's the first one I have had and it reminds me a little of 'The Georgina' engine by Tubal Cain.

After some soaking in penetrating fluid and an initial loosening/dismantling the engine is moving. It needs some major surgery on the wooden base and I had to drill out the fixing bolts as they were so rusted. Mysteriously the shell bearings are present but only the bottom half so there's a fair amount of lift as you can see from the video.

The other fixing bolts look solidly rusted, but I'm hoping I don't need to undo them as eveything looks repairable from the top .......let's see........

https://www.youtube.com/shorts/xTyVoci2dPM

Sanjay F:
Wooden base and underside of base plate

Jasonb:
Half bearings can be found on some full size engines. Traction engines spring to mind where there was just a bearing to fit the top half of teh rear axle as that is the side that took all the vertical load.

Seems to be turning over freely so give it a whiff of air.

Sanjay F:
Oh right, I never realised that........there's definitley brass on the bottom halves, when I lifted the crankshaft up

actually now looking at the bearing caps there doesn't look like there were any top halves to the bearings and not sure if/how they could have been fitted. I guess the mass of the flywheel is meant to hold the crankshaft to the bottom bearing shells. I believe these engines turned over slowly so there wouldn't be a huge amount of sudden lifting force?

I tried some air but its leaking from every and all possible places; I also can't get a good seal around the inlet so will need to make and fit something suitable. I'll dismantle it clean it up, repack the glands and piston (if needed) and see what happens ....I think she'll run (fingers crossed)

Sanjay F:
I had to investigate further and started the disassembly  ;D

This must be a single acting engine as I cannot see any holes at the bottom of the cylinder and only 2 ports in the valve chest? I've not played around with one of them before....

I drilled through what was left of the inlet pipe and tapped a new thread so hopefully there will be a good seal once rebuilt. As you can see there's nothing left of the gaskets and the piston, piston rod and valve rod are rattling around with either worn or no packing.

The crankshaft and flywheel spin smoothly without the bearing caps so I'll assume as Jason has suggested they must be 1/2 bearings

https://www.youtube.com/shorts/5fuPLtFs65o

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