The Steamboating Forum

Hi from Nigel White operating steam launch Harlequin on the River Thames in Oxfordshire. I have owned Harlequin for 2 years now, more details can be found in the steam boat register. I have a problem with the engine that I need some help or information for. The engine is a single cylinder David King (of Norfolk, UK) 21/4" bore, 21/2" stroke. I am pretty sure the piston rings are cracked or seized (or worse) but I cannot find out how to open up the cylinder. There is no obvious cylinder head, just a 1" domed steel cap tapped 3/8" with a bolt which when removed allows me to see the top of the piston and the retaining nut on the piston rod. Under the dome is a freely rotating cast brass disc with the makers name. Reasonable force with a 14" wrench has not moved the dome!
At the bottom of the cylinder block is a lightly knurled collar into which the piston rod gland screws. Due to the arrangement of the pillar casting it is virtually impossible to gain any purchase on the collar to try and unscrew it assuming it is a screw fitting into the bottom of the block. There are no obvious fixings between the cylinder block and pillar castings or any evidence of a separate cylinder head. Photo of top of engine attached.
Any help or information welcome.

Thanks Nigel

Welcome to the forum Nigel.

I'm afraid I don't have an answer for you without handling it, but I can tell you that some engines don't have cylinder heads/covers as such, and the piston must be accessed by removal of the block.

There are others on here who may have direct knowledge of this particular engine.