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SimonBrown

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  1. Jon - this is one of the finest threads running here. Nothing short of remarkable. Keep at it and don't let the obstacles grind you down!
  2. Progress has stalled a bit as I have been busy on other things Scapa Flow related. A week of frustrating-at-times diving proved useful with a few new finds, plus documenting stuff like the Anti Torpedo Close Protection Pontoons at Flotta: 3D model of a pontoon. But I shall be back on the torpedo engine tomorrow - fingers crossed. I have also taken a close look at an 18" example recovered from the sea. Its in a bit of a state but could be worth preserving. The steel has gone but lots of bronze parts remain. On the 18" engine the cylinder heads were steel and have rotted but it did mean I got one of the set-circular gudgeon pins out of the bore without so much as touching a spanner... The rust is all that remains of the con rod. It crumbled like dust so not sure this one will be a runner again soon...of note was the piston ring. They are made of bronze and have survived well, if a little caked in rust.
  3. Last call for brown envelope style offers before we put the torpedo engine on Fleabay...anyone mad enough to want one? Now is the time... And we also have a Mk23 21" dummy warhead available: We have no idea what is inside it, but its heavy. Open to offers before its disposed of. Just PM me.
  4. Having seen how popular the 8-cylinder torpedo engine restoration has proved, I thought I would offer a 4-cylinder example for sale here. We think its a Mk VIII engine, a four cylinder two-stroke diesel example that appears to be complete. It has not been raised from the seabed and is in pretty good condition. Its possible its never been tested, let alone used. I would add this to my collection, but a) SWMBI would start to question the sanity and b) its being sold to raise funds for an ongoing project. The project we are working on is the story of the stolen Hercules C-130 that crashed in the English Channel in 1969. Last year we found the crash site, so now its time to dive it and investigate...all proceeds go in the pot to cover boat diesel costs. Its bronze and heavy thus attractive to the scrap man, but we would rather it go to a deserving home. We are open to offers on this example of superb engineering. Collection will be from either Weymouth or NE Hampshire. Go on...you know you want it...
  5. Not much progress of late, but things are cleaning up nicely and the gummy preserving oil is coming off a treat. On the right, pot No 3 cleaned and lightly lubed and on the left pot No 4 waiting its turn. Most of the pistons have some light scoring on the skirt but nothing to worry about. A scrub with degreaser is shifting the muck and the rings are now free to move in the groove. Barrels have been given a dunk too: And the bores are pristine: Note the two oil grooves halfway up the bore. Only one is pressure fed via the external pipes, with the other not aligning to any oil way I can see. Thinking about the big end...if it ain't broke don't fix it springs to mind. Its clean, rust free and rotates smoothly. Plus another special spanner is needed to get to the large nyloc holding the big end together. So I'm inclined to leave it and clean/reassemble from this point. Its still a work of art though. Heres a side view: I think the 'F' stamp stands for 'Front' but I will know when I turn it over and see if the rear set of con rods are stamped. Here's a view looking down: You can just see the big end nut above the main bearing. Here's a closer view: Access is tight and I think a standard socket and extension is going to clash with the square section next to the main bearing. Its such a compact unit. Quite remarkable the power output crammed into a 21" diameter tube. The pan head screws are treated to a dunk in the ultrasonic degreaser before having a die nut run down to clean the threads and the inlet valves are coming up brand new. Takes about an hour per pot to fully degrease, with 3 down and 5 to go.
  6. I can only echo that. Keep up the good work!
  7. Isn't it just? A real joy to work on, if a little fiddly at times. A puller has occurred to me. There might be risk of the caps being pressed in so tight the threads strip, but a puller could work. For now, and unless I can find a good reason, the pistons will stay on their con rods. The true purpose of oil feed into the cylinder is not something I had considered, but the idea its spraying over the little end bearing sounds perfectly logical and given the power output absolutely necessary. I will have a look at it again when next in the garage.
  8. I did promise a while back some photos of the gudgeon pin-less design. Its not easy to get your camera in - even a slim one like an iPhone - but here goes... Two bronze or brass caps are pressed into the piston and retained via a split pin. The brass caps extend deeper than the piston skirt and into the area under the piston crown. The caps are fixed and do not rotate, but are machined with a large flat on the side facing into the crankcase: Under the crown of the piston and fixed to the top of the con rod sits a solid bronze semicircular shaft that extends beyond the con rod and over the brass caps. The semicircular shaft is machined so that the piston can rotate about this shaft on the brass caps. The internal Admiralty threads may be there for no purpose other than to help in a manufacturing process? The load from the piston appears to be transferred to the con rod directly to the semicircular shaft and the brass caps are then to keep the con rod in place, but transfer no load whatsoever on either the induction, compression or power stroke. Is like nothing I have ever seen before and the conclusion is space was at such a premium they dreamed this up to reduce the overall diameter of the engine. I would imagine it might clatter a bit when running...which seems odd as sound travels well underwater and it might alert a hydrophone operator something was starting up...thats guesswork at the moment though. How it comes apart - if it ever can - is today's conundrum. Right now I'm fairly relaxed as underneath the crowns looks clean and lubed, and no corrosion.
  9. Isn't it just? Its going to get better...read on... Been thinking about what to do with it once the job is done? Inclined to mount it under a thick piece of glass and turn it into a coffee table...or just leave it on its stand in the living room and marvel at it every day...chances are that idea will be vetoed quickly by SWMBI. Starting to clean things up and No 1 cylinder & parts have been degreased. The good news is the gummy preserving oil holding the piston rings in cleared up and the rings are now free: Still not turned my full attention to removing the pistons - One of the bronze bushes was pressed/tapped to see if it would move and the short answer is "Not without more force than available right now" so they have remained in-situ. The thread, in case anyone is wondering, is another Admiralty pattern (The thread chart here has been used many times - thanks MatchFuzee) 5/8" with a 20 TPI pitch. I am now thinking the bronze bushes are pressed into place as a one way trip and may prove difficult to press out again, as its likely there would never be a requirement to strip and service. The degreaser has worked its wonders. The barrel was left to soak while all the nuts and pan head screws went into the ultrasonic cleaner with a 30% degreaser/water solution: Now its cleaned off its pretty clear the barrels are plated on the outside, and its probably a nickel finish. I suspected this as when the inlet manifold unions unscrewed some of what looked like plating peeled off and galled in the threads. The plating is peeling as 70 or so years have taken its toll: Now, a nickel plated set of barrels is going to look simply jaw droopingly beautiful, 8 of them gleaming like new. But should they be replated? Or do we leave the patina? For now, an issue to set aside as there is still plenty to do elsewhere.
  10. Next up we have a pair of 4.5in naval shell cases. They have been recovered from the sea and do have a nice patina (I was thinking garden ornament...but the missis objected...). Not sure of dates or base markings but can check tomorrow if anyone is interested.
  11. A friend of mine is having a garage tidy up, to make space for some 1970s classic two-stroke bikes and to raise some funds towards an ongoing project. The project has been to find and investigate the crash site of the C-130 Hercules that was stolen by Sgt Paul Meyer in 1969. BBC Radio have been following progress last year and right at the end of the season we found the remains of the aircraft. This year we will be diving and mapping the crash site and to help defer some of the boat costs the torpedo collection is being disposed of...and all monies raised will go on the project. First up we have a rather unique piece, a practice warhead for a 21" Mk 23 torpedo. As far as we know its intact - less the bang - and we can only guess what is inside the nose cone...typical torpedo fashion it needs a special tool...Its heavy: Obviously one for the collector of such things. We really have no idea the value, but are open to serious offers and would prefer to see it go to a good home - hence offering it here first. Collection from NE Hampshire or Weymouth please - just drop me a PM if interested.
  12. Direct acting cams - basically turning at same speed as the crankshaft - will only work (I think) with a two-stroke engine. A four-stroke radial engine would still need a 2:1 reduction on the camshaft, so it rotates at half crankshaft speed and makes sure the inlet and exhaust valves open once every four strokes. If that makes sense? Thank you! More to follow as and when.
  13. Well spotted. All the external pipes (that have now been removed) were oil feed. Each inlet valve had a direct feed, and each cylinder is lubricated in the bore via the hole you spotted. As of now I have yet to find any way a pressurised oil feed fed the big ends, but there are four nozzles on the rear crankcase cover that would blow an oil mist over them. The offset slots on the piston crown? Purpose and reason unknown, but they may line up with the blanking plugs - I will check. Either way, purpose unknown.
  14. The cam removal can now be ticked off the list. But more of that later. The rest of the barrels were pulled today: Which gives us a much clearer view of the slightly insane yet compact design of the big end and its four con rods: The bronze big end bearing can be seen with the con rod running under the retaining lip. With the pots pulled it was time to sit the engine vertically on the bench. A 100mm hole saw put a hole in the bench for the drive shaft. With the cam castellated retaining nuts removed an alloy drift knocked said cams off. A snug fit but not a press fit, that one: A few more the pan head "studs" that hold the barrels on came loose and after cleaning up a small pip can be seen under the head of the screw: Which looks like nothing more than a blob of solder. This was intended to stop the pan head screws from turning in the crankcase as the nuts were tightened, but 70 years of crud meant they were not coming undone. The debate I am running in my mind now is do I revert to solder and keep it original? Or do I reach for the Loctite? No reason for this photo. Its just engineering and engine porn and I make no excuse for sharing it: The pistons do not have a traditional gudgeon pin and I will turn my attention to these next. All of the pistons are numbered and some have what appears to be size/tolerance numbers stamped. Its a neat design and will get some more photos of how the pistons are held in place without a gudgeon pin. Its clearly an expensive way to make an engine, but driven by demands of a 21" tube and a buyer willing to pay for it then who can blame them? In the meantime, the engine sits on the bench and looks rather fine indeed.:
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