The Steamboating Forum

Hi Guys, I hope this works I haven't posted an image on here before.

I recently came by the engine in the picture but am having difficulty identifying it accurately. I think the top and bottom have been 'married', the cylinder casting would seem to be ST5A but the bottom end is nothing like the 5A drawing.

The crank throw is 2", the bore may not be to the original spec but is 2.25", there is a packing on top of the column, under the cylinder and therefore I think the pillars have been made to match.

Anyone any clues as to what it's heritage might be?

Other images are available.

As far as I know, the only Stuart Turner engine in that size range with that sort of crosshead is the #1. But I suspect that what you have might be a one off design using the 5A cylinder. Nice motor though.

Thanks for that thought Mike, the cylinder has "5A" cast on the side, but apart from the "S" on the valve-chest I have yet to find any other markings. The crank balance weights are bolted on, not cast/forged/etc. and there was a saddle type guide fitted under the v/chest which I'm not sure is original or really necessary.

I think she's a pretty little thing, and it should be possible to make her useful as well.

As regards the ST No 1 theory, on checking, the configuration is the same, in that the cross-head guide is single-sided, but the column on a No 1 has a curved rear face not straight like this one. So unless there is a more definite identification I could be leaning towards the 'one off' theory.

Work on it progresses, I've cleaned up the cylinder and end cover, made all the missing studs, and decided on a mod for the reversing gear. The missing valve-slide has been roughed out from a nice chunk of Gun-metal. Still a way to go, but progress is progress!

What are your plans for it? I have a mostly completed #1 and I have given some thought to extending the piston rod though the top cylinder head and adding a water pumping cylinder on top. Thus building a flywheel feedwater pump.

Mike

Currently I'll be happy to see it run on air, beyond that could be a whole other kettle of fish. I've got some nice hardwood laid by to make the cylinder lagging, so it could even finish up a shelf queen, but that would probably be a shame. Too soon to be sure.

Work progresses slowly round here - too many distractions; but so far, I have finished off the new slide-valve, made a new port plate, re-fitted both eccentric sheaves, made a couple of piston rings and re-fitted the big-end bronze. I could find no means of lubing the big-end 'til I removed it, and there, was a hole in the crankshaft journal. Applying air to the hole it seemed to leak all over and on tracing it I found several of the drillings hadn't been blanked (or even tapped for same) having sorted that I then couldn't get the air to go anywhere, so lifted out the c/shaft. Now I presume, correct me if I'm wrong, there should be a hole in at least one of the main journals to supply oil into the shaft for centrifugal force to push it to the big-end. My dilemma is I cant remember if there is a correct radial orientation for that hole, and if a feed-groove should be round the inside of the bearing, as would be the case with a pumped oil feed.

Thoughts anyone?

Where does that hole in the connecting rod "big end" journal connect to, the crank main journal presumably?

Fred, yes the cross-hole in the big-end journal connects to a longitudinal hole through the centre (which wasn't blanked) that connects with a hole drilled down the crank-web on the right. That connects with a hole bored the length of the C/shaft tail, again not blanked. Thinking about it further it could be that the intention was to just oil the big-end with an occasional squirt into the C/shaft end, but not too reliable, and probably messy too.

A steady, light drip feed from an oil cup on the main, would be a neater solution.

I built a 5A for a generator application and fed oil from a metering pump into the end of the crank. I got the pump from a motorcycle junk yard. It was intended to meter oil to a two stroke engine. Variable stroke and handled chain saw bar oil just fine. I also had the crank drilling feed the two main bearings.

Mike