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SimonBrown

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Everything posted by SimonBrown

  1. Well I am glad its not just me then! Wait till you see the big end. I have peered into the crankcase and have never seen anything quite like this bad boy before. Single big end journal carrying four connecting rods none of which have end caps...Someone wanted a very compact design and the engineers delivered exactly that. Hopefully a new tool will arrive in the next week or so and I can get the cam off to reveal all.
  2. Its a pleasure Andy. TBH I was a little surprised in the interest. I thought it was just me being curious.
  3. Yesterday's foul weather meant other outdoor stuff could wait. So what better than to get a brew, put the radio on a progress the engine? The first inlet valve was removed from the cylinder head. It would be possible to do this with the cylinders in-situ but much easier on a bench. A quick bit of fettling on a section of aluminium tube and a valve spring compressor tool was sorted. The valves themselves are unusual. I shouldn't really be surprised any more but I was left wondering "Why do that?" while peering at a very fat but hollow valve stem. The conclusion reached the hollow bit was to reduce unsprung mass, but why such a large diameter stem? The original lapping marks are still on the valve and will need no work before reassembly. Each inlet housing had a oil pipe connected to it, and originally I thought these were for fuel injection. Now disassembled its apparent these oil pipes are for lubrication, with each of the 8 valves having its own oil feed. So...the air/fuel mixing must have occurred before reaching the inlet manifold. A dig into some of the documents from the National Archives for a MK VIII 21" torpedo reveals fuel consumption in the range of 60-70 oz/min at 200psi. So pressurised fuel was sprayed under pressure into the manifold. This part - the injector - is missing from the 8-cylinder example but they do quote the nozzle diameter of 0.04" so there is something to start with, as opposed to a blank sheet. Somewhere, out there, a pair MK VIII torpedo fuel injectors must exist? The bronze lump from the aux end - the finely machined barrel and its fine gearing - was originally thought to be some form of fuel injector. Clearly its not, but it is distributing lube oil around the engine. That goes some way to explain why I couldn't find any hint of timing marks on the gears! The next job was to make access to the remaining cylinder head bolts a little easier and remove all 16 1/4"BSF studs that hold the cylinder lubrication feed pipes. Most came undone with a pair of nuts nipped up and only a couple will need a stud extractor:
  4. The engine has taken a back seat for a bit. Mainly while I progress a couple of underwater projects, one of which is scanning an entire 52 acre lake in 3D. I will share the model here, if only for the tenuous link that there is the hulk of an AFV432 sitting in 24m of water: Section of quarry with AFV432 But with that processed and out of the way it was time to crack on with the engine. First up, the tappet rollers from all even numbered cylinders were pulled out. This proved to be the easiest job of the day: Then it was time to get the cylinder bolts undone. After slimming down a ring spanner to wafer thin, the nuts were removed. Space was a premium: Now the it appears that the cylinder heads are held down with studs. Not so. Of the 12 fixings, 8 are pan head screws: And when viewed from inside the crank case: There is two visible in the above image, very close to the cylinders. Now, true to form several of them started to rotate with the nyloc nut. This proved to be a PITA and needed another special tool knocked up on the bench grinder and careful filing: Its a knackered 1/2" allen key I have had lying around in the toolbox for about 30 years. Kept for no good reason apart from "It will come in handy one day". And so it did. Not easy to access, but eventually they all yielded and bingo, the first cylinder slid off the crankcase: Now its pretty mucky inside, but in excellent condition with remnants of preserving oil oozing from every pore. The purpose of the oil pipes that were running into crankcase next to every cylinder is now understood; its injecting lubricant directly into the bore and presumably finding its way down to the big end. After initial success the predictable happened and the worlds thinnest ring spanner split when attempting the next cylinder. A crows foot spanner is on its way and progress should return. The gudgeon pin appeared to be held in place by a split pin, but on closer inspection there appears to be no gudgeon pin at all - not in the traditional sense at least - and after the split pin was removed closer inspection has left me wondering how this assembly goes together, and apart. I will post up some pictures soon.
  5. The tool arrived in the post this morning. The inlet valve caps had been soaking in penetrating oil for a few days now, but of all the fasteners on the engine these gave me the most concern. They were as tight AF and were completely bespoke and unique. These really needed to come apart with as little grief as possible. The tool fitted a treat. No fettling required and no slack. An extension bar was needed, but 7 of the 8 made that satisfying crack as they undone. The last one needed a little heat, but soon gave up resistance. All 8 are now undone. Typically, all valves carry the '113' engine number and a single digit indicating what cylinder they relate to. The cap in the image above didn't come from No. 6 pot - its stamped '2' and just happened to be lying on the cylinder! A really big 'thank you' to John for his skill, time and effort making up and sending the tool. Much appreciated as the caps have remained unscathed or damaged in any way. Next step will be unbolting the cylinder heads. I think a 5/16 Whitworth crows foot spanner has been located.
  6. The Whitworth thread gauge is a very, very close match certainly on the TPI and thread angle. Just a hint of daylight - pinprick no more - on the root of the thread.
  7. I did offer up a 19 TPI thread gauge and it was close but there was daylight, whereas the 20 TPI was spot on. The Admiralty thread looks absolutely spot on. I'm going to measure the OD of all 6 of the plugs and see. I'm using a vernier calliper, not a mic, so it will be near enough I think. And having measured the sample, I think we have a match. All are within 4~6 thou of the stated OD - many thanks MachFuzee, its a thread I had never heard of before.
  8. It looks to be a parallel thread with a machined face on the underside of the small flange. Thanks for the suggestion - will have another look with that thread in mind. I tried a 1/4" BSP thread (had a fitting lying around) and whilst it wound in, it was like throwing a sausage up Cumberland High Street (slack) as they say. The 55 degree thread gauge fitted near perfect snugly on 18tpi, so maybe not NPT?
  9. More time to tinker with the engine. A new tool arrived so the cylinder head plugs were tackled. 6 of the 8 cracked and undone. Two have not, refused to budge even with heat on them and the 1/4" square drive started to give. Looking at some of them, it looks like I'm not the first to have a go at undoing them. Above; the plug is out and on this cylinder the piston is about as close to TDC as it gets. There is very little clearance. Now in typical torpedo fashion the thread on the plugs is non-standard - or at least as far as I can tell: O.D. 0.545" 18 TPI And that matches nothing in my Zeus data charts... Anyone recognise it?
  10. John - that is brilliant - thank you so much. There really is no rush on this one, the project reminding me of patience in this instant-gratification world.
  11. The thread gauge arrived today. Its needed because some of the inlet manifold coupling threads suffered galling when removing them. Have a look at the image above - the first couple of threads have been damaged at some point in the past or during disassembly and need a bit of TLC before reassembly. Rather appropriately the thread gauge is dated 1952 and comes with the crows foot...nice to have a contemporary tool complete with its original cardboard box. Now the thread appears to be 1-5/8" (1.6250"), a rather fine 20 tpi and Whitworth form. The usual searches (Ebay and Google) reveal this thread exists, but tools are as rare as the proverbial rocking horse dung. Anyone have a die or die nut lurking in the tool box? Long shot I know...
  12. A Whitworth crows foot spanner should be (or was...30+ years ago maybe) an off the shelf item, something like this: Bacho crows foot spanner If push comes to shove it looks like 15mm AF metric crows feet spanners are widely available, and with a little bit of fettling (5/16W spanner = 15.25mm across the flats) it could be a solution. Now...if you fancy a challenge then I will need a tool to get the inlet valve covers out of the cylinder head. When it comes to blanking plugs I have never seen anything like this bad boy before. Shown here in the lower left, the 8 pointed star shaped recess: Knowing I will need something come what may, and someone on here might just recognise it as an X plug from a YYY type of vehicle and the tool is off the shelf (I know, zero chance...but you never know) here's a dimensioned drawing of what is needed: Not being a toolmaker, I have not made any allowances for fit - the above measurements are of the recess itself and all dims in metric. There is a lot* of work in making up such a tool...if its a challenge needed... *thats a conservative estimation.
  13. Tool appeal: Does anyone have a 5/16 BSW or 3/8 BSF crows foot spanner lurking in their toolbox they would be willing to sell? 1/4" or 3/8" drive would be perfect. The cylinder bolts are difficult to access and whilst a ring spanner is about to go under the grinder, a crows foot spanner would be a great help. Even the internet agrees they are a rare thing - couldn't find one - but folks here might just have one not required and lurking in the depths of the toolbox?
  14. It was time to stop fussing around and get the manifold off. Plenty of heat, aided by youngest daughter directing the blow torch onto the coupling, and a long extension tube on the C spanner did the trick. Finally shifted them and (crucially) with no damage. Wrestling one of the sections off the motor was fiddly, and it going to be fun trying to get that one back on. The complexity may well have been the killer of this idea. There is plenty of power in a very compact space, but the manufacturing and assembly plus any in-service work would have been expensive. Glad I took the manifold off. Found my first bit of rusty crud in one of the inlet ports: With the manifold out of the way the rest of the fuel pipes came off. Some route to/from what I thought was the fuel distributor, but I am wondering if they are not spill/return pipes? More investigation needed. A bonus was finding inspection stamps on each of the cylinder castings, just next to the integral fuel injectors: The only other time I have seen stamps akin to this are on aircraft components. Presumably stamped at the Whitehead works in Weymouth, they need following up at some point.
  15. With a single original track segment it could be scanned using photogrammetry - just like the torpedo motor I'm restoring - with the advantage it would be easy to make it a closed & therefore solid model. It would need work post-scan to add material to any worn sections, add material to the track pin bore and scale it to take into account the shrink factor when cooled, but the beauty of a 3D model is much can be tweaked and changed at very little cost and verified with a 3D print before committing. More than happy to help on this one, if photogrammetry is of use?
  16. It took longer to assemble the borrowed hoist than it did to get the engine onto its stand: The inlet manifold threaded connectors are proving to be a PITA. Three of them have come undone no bother, but the rest are tight AF and are refusing to budge even with an extension bar on the C spanner and applying loads of heat. Its as if they were welded up but there's not sign of that. I'm heating them with a blowtorch and allowing oil to run into the threads as they cool, but if anyone has any other ideas then feel free to chip in: I couldn't resist a peek into the engine internals so I pulled the auxiliary drive cover off...Wow was the first reaction: Everything is numbered to its relevant pot, which will make reassembly easier. Plus, it looks like we have an engine number of sorts: 113 is stamped on every component I can see so far. I had seen this stamped on one of the poppet valve covers and wondered its significance, but with everything carrying the same number + cylinder number its a logical conclusion: Degrees stamped on the cam presumably relate to valve timing, but will verify at some point. After drooling over the engineering I slipped the cover back into place and carried on heating and soaking the inlet manifold glands.
  17. A few hours spare over the last couple of weeks has got the adaptor sorted for the engine stand. Closer inspection of the crankcase housing reveals its an aluminium machined block, not a casting. It will be interesting to get the aux end cover off and peek inside. I got some steel blanks plasma cut. Ordered online to the exact size I wanted, including the flange: Holes needed marking and drilling but the steel blanks were perfect and burr free. Quick loose fit of the flange confirmed the marking out was close enough. And the main mounting plate lined up too. After tack welding the spacers in-situ I took it off the engine to put a bit more weld around each. With my welding I was not planning to rely on the strength of the fillets, but by weld No 28 of 32 quality was improving: And final fitting, ready for a lift onto the stand: Next few days should see the engine off the floor and onto the engine stand. Then its back to stripping the motor down.
  18. At the point I was pulling this bit apart I wasn't really sure a) what it was and b) how it came apart. With no manual it became a bit of trial and error until I realised the distributor barrel was machined to very fine tolerances and it was 50~70 year old gummy fuel residue putting up resistance... but until that point the last thing I wanted to do was force something and inflict damage what may be the last of its kind. In the end, it took a gentle but persistent push with some penetrating fluid down the bore and ports and it slid out with nothing more than finger pressure.
  19. A little progress this weekend. The rusted split pin was drilled out and the last set of fuel timing gears were freed from their bronze casting : Two 'C' spanners were welded together to fit the exhaust coupling slots better - but I'm not sharing photos of that. Its been 30 years since I last used an arc welder and lets just say it shows. The welding is good enough to hold them together and work as a pair, but not quite display material. Friday the engine stand I ordered turned up. Whoever designed it had never envisaged it being used to support an 8-cylinder radial 2-stroke diesel engine, so some lateral thinking/cutting/welding will be needed to hang the engine off it and not cause damage to the aluminium crankcase in the process. But if I'm being honest, its solving problems like this that makes it all the more rewarding.
  20. With an hour spare, more progress. The bronze lump on the aux drive end is almost certainly for fuel distributor/injection timing. With a bit of penetrating oil, lateral thinking and gentle pressure the large cylindrical barrel slid out of the housing. The barrel has a series of ports, each of which have a sliding block (the copper-looking rectangular bits in the image above) that marry up to an array of ports that have been drilled into the bronze liner thats been pressed into the casting. You can just see the bronze liner above. From what I can tell - and I need to stick some fluid through it to prove it - the four ports at the bottom (you can see three above) are feeding pairs of cylinders. The exact timing is unknown. The rest of the gear assembly came apart a treat, with just one rusted split pin refusing to budge. That will need careful drilling next.
  21. The hydraulic platform warranty repair arrived this morning. Lots of excitement, with all hopes dashed when the load bed refused to lower when anything of any mass was placed on it. Back to square one with a refund now heading my way. Disappointment did not last when the postman arrived with a package containing a set of Britool BSW sockets. Shiny, quality tools are always a joy to work with. The 'C' spanner arrived too, so it was time to start work on stripping the engine. The inlet manifold is made up of several sections and the 'C' spanner managed to undo the first 3 couplings no bother. The joins are sealed with some very fancy copper washers. The rest of the unions are stuck fast and refused to budge, even with a little percussive maintenance...so they are soaking in penetrating oil now while I acquire a decent blowtorch and get a bit of heat into them The sockets went to work on the aux drive end of things - the bronze yet-to-be-identified parts at the rear. What I thought was an oil pump may well not prove to be so after stripping. Its a geared, two speed affair with a set of unidirectional dog clutches. Its purpose remains unknown...however, sitting under this body was a gear pump. The galleries leading from this pump lead deeper into the engine body, so at this stage I'm guessing its for engine lube. I'm not sure there is a sump and it reminds me of a JAP speedway engine fitted with a pilgrim pump, so called as the oil goes just one way so my dad told me. The design of the gear pump does now tell me rotational direction of the engine, if nothing else at this stage. Next up, the bronze end cover/oil pump housing came off to reveal the outer end of the crank main bearing. From what I can see its looking near-brand new inside, which means we are not dealing with a seawater flooded pile of internal rust. Overall, the engineering is pretty impressive for a motor designed to function just a few times before its terminal destruction.
  22. This policy shall be the guide I think. Thankfully this engine has not been in salt water for a long time - if ever. Its only light surface corrosion so far. I lifted a cannon ball from a wreck site we found on Chesil Beach after winter storms uncovered the pile of cannon and shot. That was about 5 years ago and as far as I know its still in a fresh water bath, encouraging the 300 years of salts out of the iron and back into solution. Had the engine been raised from the seabed I think it would be in a far worse shape. That sounds just the ticket. I will have a hunt around - cheers!
  23. Thanks for the measurement. The manifold inlet on the 8-cylinder is approx 1" dia, so its a useful comparison and it triggered a read of the archive docs. From the records I found performance specs from two 8-cylinder engines, with swept volumes of 406 cu in (6.65l) and 460 cu in (7.53l) respectively. The former was listed as built, the latter listed 'design delayed'. When Britain entered the war effort shifted from R&D to production, such that by 1943 we had more torpedoes than we needed, but it was acknowledged any R&D would not be in service until the war ended. Air consumption for the 8-cylinder that had run is listed at 269lbs of air - which converts to approx 94,374l of air for a 60 knot run for 148 seconds/5000 yards! . By comparison the standard 4-cylinder Mk. VIII & IX 21 inch engines consumed 141lbs (49,467l) of air for a 45 knot run for 197 seconds/5000 yards. A typical 15l dive cylinder at 232bar will hold 3480l of air...so if my maths is right we won't be running the motor for too long. Which considering its age and rarity is perhaps no bad thing? On the other hand, divers like myself use enriched air - breathing gas mix with anything between 21%~100% O2 - for reducing risks with decompression sickness...and the Japanese did indeed put enriched air torpedoes into service...given the risks dealing with high pressure O2 this idea will need to go through the "Can I? Should I?" filter more than a few times I think. I digress. I really am in two minds with what to do? Preserve the patina or restore to look new? Only get one bite at this cherry and once done there is no going back. Preserve is now under consideration. Could you share a link to such products? The main body is aluminium.. There is a brass component on the aux end, its purpose currently unknown but is (I think) either a lubrication pump or an incomplete fuel pump. It does have a nice patina...I have created some highly detailed images (called orthophotos - 1mm per pixel is a typical scale, great for recording stuff under water) that act as a permanent record of the motor before I touch it. The aux view of the engine can be seen near the bottom of this link: Orthophotos of torpedo engine. So...keep the patina? Or return to the as-manufactured look?
  24. Well, the good news is the garage is well stocked with dive kit, and 250bar cylinders are in abundance.
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