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JohnD

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Everything posted by JohnD

  1. Whereas here on the sunny Costa del Morecambe, situation normal!
  2. Which did you mean, Roger? This one? That three pinted catch looks steel to me. Or this one Where the yellow finish is just anodising, on steel. Dave, show us a pic, please! John
  3. We had a similar conversation here recently, about annealing copper. I was corrected about slow/rapid cooling, and learnt that copper, unlike steel, is softer after being quenched, in water. But I would still say that a washer cools so quickly in air that it will soften well enough. But here, the copper/brass needs to retain or regain its temper. So I ask the metallurgists - will a slow cool have that effect? Will burying it in sand allow it to cool slowly enough?
  4. JohnD

    Hydrogen

    Flour-powered (!) engines may be the future, after all, flour is a renewable energy source, BBB it in the past coal-dust has been used as a car's fuel. See: https://www.cnet.com/roadshow/news/gm-coal-powered-turbine-chrysler-leno-ecojet
  5. JohnD

    Hydrogen

    Self igniting haystacks have long been a farming risk. After I left school, I had a job as a lab boy, for a scientist who was researching just this - and that was in the mid '60s! He investigated the proteins in the straw, and I set up the AutoAnalyser runs on the products of digested (with acid) straw, and then cleaned the glassware. I never did learn the result of his research, but I did learn for the first time the value of PPE. Chromic acid is fierce stuff!
  6. JohnD

    Hydrogen

    But is hydrogen explosive? Certainly it will burn, and burn fast, but so will a sheet of newspaper. Now as amateur engineers and engine tuners, we all knwo what a stoichometric mixture is, so what will happen if you ignite such a mixture of hydrigen abd oxygen? Let the eminent and delightfully 'mad scientist' (he is most definitely sane!) Sir Martyn Poliakoff show you! So ruptured tank of hydrogen is a severe fire risk, but not an explosive risk! John
  7. JohnD

    Hydrogen

    Since when was that not true of any other motor manufacturer? EG For my modern, I wanted the little plastic trim that covers the door lock. Certainly Sir, that will be £330. They would only sell it with a complete door lock and handle system. And I've told of the Citroen reversing sensors that are tagged so that you need to buy an identical unit for twenty times the price. It's long been a fact that they make their cars for break-even and their profits from parts. In a supermarket it would be called a 'loss-leader'. Flour bomb? Now I did NOT expect this JOhn
  8. JohnD

    Hydrogen

    Ze Chermans? Not ze law obeyink? Sicher nein!
  9. JohnD

    Hydrogen

    And blocking access for the emergency services? In Germany it is the law that when a motorway is blocked, drivers must move aside in their lane, to leave an access corridor, even if there is a hard shoulder. The lack of such a law in the UK is another reason for "smart" motorwyas being so dangerous. John
  10. Thank you, All! I fear that Spitfire fitment is a red herring, as AFAIK, all six cylinder camshafts had the same sized journals. The camshaft I want to fit is with the machinist, but again, AFAIK, it has the same sized journals as a standard camshaft, of which I have several, and they all have journals the same, all along the shaft. I've measured the ODs of this one, and the ID of a set of camshaft bearings I just happened to have on the shelf. They agree at 1.865". See pic. So I don't where 1.9... comes from except the Spitfire engine. Thnak you, Pete, for your gut instinct of one thou tight. I have found a Rule of Thumb on the site of a non-Triumph engine builder, 0.7-1.5thou per inch of diameter. This means 1.3 to 2.8 thou and maybe 1.5 thou tight will do the job. If it's too tight, then I must ask the machinist to hone the bearings. John
  11. JohnD

    Hydrogen

    Above, it was pointed out that hydrogen is an explosive gas, and the Hindenburg Distaster cited. This happened two days ago, on the M11: https://www.facebook.com/neilgossage/videos/886127245444672
  12. JohnD

    Hydrogen

    Eighty four actually, never could do mental arithmetic! Why are you so unhappy, BW?
  13. JohnD

    Hydrogen

    To which of your friends and family do you refer, BW? The Hindenburg disaster was ONE HUNDRED AND FOURTEEN YEARS AGO!
  14. No! The bearings fit the standard journals, so the block must be bored. Yes, no doubt that ever-pennypinching Triumph abandoned them to save money. So to return to the question, how much smaller than the bearings' OD should the block be bored, to achieve a satisfactory interference fit? In case you haven't seen one, they are complete rings, unlike main and big end bearings. The steel backing has a 'jigsaw' shaped joint - see below. This cannot provide much movement :
  15. JohnD

    Hydrogen

    Hydrogen is a carbon free fuel, but there is no natural source, only 'Grey', 'Blue' and 'Green' hydrogen. Grey is made from fossil fuel, natural gases at the refinery. The waste from that process is, surprise, surprise, carbon dioxide. No benefit. Blue, sequesters that CO2 somehow, so as not to release it into the atmosphere. Another process has solid carbon as the waste, which may be easier to store, and this is 'turquoise' (greener than blue!) hydrogen. High energy demand just for the processes. Green, is made by electrolysing water using electricity. The only 'waste' is oxygen, that is of course used up again when the hydrogen is burnt. But the source of the electricity should be not from fossils, else it is not green. Electrolysis is about 80% efficient, but then, for transport purposes, the gas must be compressed and transported in heavy cylinders at 10,000psi ! Compare, say Oxygen that is stored in cylinders at 2000psi. So that the efficiency of the whole process is worse than a modern ICE, about 30%. But 'clean'! John
  16. With respect, I'd like advice on fitting the bearing to a six, please, not a discussion of Spitfire fitments!
  17. D'accord, Roger! Lost the decimal point, somehow.
  18. I've found these specs in the GT6 Mk 1 WSM: Camshaft New Dimension Inches Clearances Inches Journal Diameter 1.8402 0.0026 1.8407 0.0046 Bore in block 1.8433 1.8448 Please ignore the heavy table lines - I didn't put them in! But what do these specs mean? Why two dimensions for the journal and bore widths? Were these the tolerance Triumph worked to? A journal width 1.8402 in a bore 1.8433 has a clearance of 31 thou. A journal 1.8407 in a bore 1.8448 has a clearance of 41 thou! Neither agrees with the stated clearances! Confusing! This doesn't answer the machinist's Q, what dimension to bore out to for bearings, but could inform the decison, if I had some illumination! John
  19. Pete, maybe you would like to suggest that to a master craftsman? Who can do the work to that precision? I wouldn't dare!
  20. I want camshaft bearings for my new 2.5L engine, so I turn to the Spitfire experts, although advice from anyone gratefully received. I've had this done before and the machinist did a good job, but he's snowed under right now and has referred me to a colleague in the next town. The new guy comes well recommended but has a different attitude so where the old one just got on with it, this one asks me, how tight do I want the cam bearings fitted? Interference fit, I said. Ah, but how tight, he replied, 1 or 2 thou undersize? Early Spitfires were fitted from the factory with cam bearings, and it's those that will be fitted, as production six cylinders had the cam running in the block, as later Spits did. So can anyone tell me? How tight should the cam shaft bore be? Thanks! JOhn
  21. JohnD

    Joke

    I would be VERY careful with that exploit, Roger! A couple of months ago, my cat bit me. She snapped at my hand, and one tooth JUST broke the skin. I washed and dressed it, even put some iodine on it, but 24 hours later, I had ascending cellulitis up my arm - evidence of a spreading infection that my body could barely fight. Untreated, cellulitis could lead to a suppurating arm and loss of fingers or even the hand, and did, in the olden days. I took myself to A&E and bless them, they sprang into action, saying that cat bites are even worse for infection than human bites - dog bites are easy! I spent the night in hospital on intravenous antibiotics - they took it that seriously! - and by mouth for the rest of the week, curing the infection. Don't treat a cat bite lightly! John
  22. Pete, how does it show the piston grade? "BAAA"? And what different grades of piston were there? I did hear that the production line was supplied with pistons of different sizes, to be fitted to the indifferently machined-out bores! John
  23. If the bores, big and main journals were STND ( at least when it left the factory!) I imagine this is an engine built to be sent out in exchange for a faulty one. Not one returned with a defect and rebuilt.
  24. I built a rear ARB for Silverback, from a Peugeot bar. It was all adjustable and I used to fiddle with it. But one day my link failed, I took it right off - and it made no difference at all! I'm not convinced that a well prepared Triumph rear axle (lowered, stiff spring) needs an ARB!
  25. JohnD

    Decibel Meter

    1&2 bone chance Mon Ami! 3 M.Langlais, Non!
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