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Peter Cobbold

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Everything posted by Peter Cobbold

  1. We humans are the biggest pollutant, all 6 billion of us.
  2. L:a Palma is livening up with tremors: https://www.mirror.co.uk/news/world-news/popular-spanish-holiday-destination-risks-24980862 The authorities in Canary Islands are likely to downplay the risks, too much tourist income at stake. La Palma is also a huge tsunami risk to Atlantic shore-lines. Peter
  3. A cool air intake is needed for optimum max power. But for best fuel economy, best mpg, a warmer intake and inlet manifold is desirable. The closer the mixture can be made to a gas rather than a mist of droplets the more consistently it burns cycle-to-cycle, the leaner the mixture can be set and the more the spark advanced. Wrapping seems to me to be going against the CC-GW agenda, if only in a minor way. Peter
  4. Wrapping was invented in the turbo era, to keep exhaust gas hot and expanded before it entered the turbo. It might decrease under-bonnet tmeperature in a TR a bit at low speeds but a cold-air intake was fitted as standard to the PI- so why wrap?. Changing to carbs and fitting air filters without a cold-air plenum might be a reason for wrapping based upon engineering rather than fashion. Peter
  5. Compulsory smart meters cannot be far off. Then rationing when the wind fails in the depths of winter.
  6. https://theconversation.com/china-is-on-course-to-build-the-best-cars-in-the-world-167661 Maybe, but if the lecky is NLA except when the wind is blowing, the best is as useless as a SInclair C5. Peter
  7. That should kill off demand for ecars once it is wider known. And plugging it into a 16 Amp socket instead of a dedicated charger can presumably be countered at peak times with smart meters. Perhaps there is method in their madness: they want everyone to stop driving, period. Peter
  8. Noting the age of many TRers I thought this post might be of interest. Dietary supplements are widely regarded as snake oil, and a "good mixed diet" is all we need is widely espoused. This article by an eminent biologist makes the point that we can function OK with a short supply of many minerals, vitamins and other key molecules, but we may well need more for optimum health long-term, for longevity. He envisages that agents in short supply are "triaged" to enable short-term defences, leaving longer-term activities un-addressed with a consequent reduction in longevity. Bruce Ames invented th
  9. https://theconversation.com/how-rolling-stones-drummer-charlie-watts-infused-one-of-the-greatest-rock-n-roll-bands-with-a-little-jazz-166719 Yes, jazz was his passion, the Stones the day job. But didnt he do it extraordinarily well ! Peter
  10. The eruption is ongoing: https://www.ruv.is/frett/2021/03/18/eldgosid-i-geldingadolum-i-beinni-utsendingu
  11. Twinkle is expert at killing the rats around the hen coops. Poison would be cheaper, but he is entertaining to watch when hunting. He was originally a stray, and survived by killing adult pheasants - he jumps on the bird from behind and wraps his frontlegs around the wings and bites through the neck - very quick. Peter
  12. Possibly far too retarded spark. Try setting the static timing to around 18 deg BTDC, which is about right for a low compression head and disconnect both vacuum capsules. If that impoves driving get the distributor overhauled.
  13. David, The very best of luck sorting all those variables without handing the TR over to a Weber specialist. Personally I'd sell them and fit a pair of SUs, the performance difference is marginal in road driving and tuning is easy. The other option is to seek out another road-going 3 with Weber 45s and copy that, if it exists. At cruise where a road car spend 90% of driving the main jet does not flow fuel and tuning involves the auxilliary jets, emulsion tubes etc to obtain the correct fuel flow and quality (atomisation). For racing all these circuits need only be approx right ( ie rich)
  14. Our faithful cat vanished on 1 July. He, or possibly she according to the vets, never roamed far but would accompany me on short woodland walks. After ten days searching the valley and asking our two neighbours - a quarter mile away - I gave up. Then last Wednesday the vets called and said the cat had been handed-in in the town 8 miles away. Twinkle had been chipped only a few months previously, when he was in the vets recovering from us poisoning him with flea powder. We never really thought the chip was needed, he never roamed far, how wrong we were. Moral: cats and chips go well together.
  15. I'm at Malvern in spirit, so have a good weekend. Hopefully next year both the 6 and its owner will be in fine tune, fit to join in again. Peter
  16. Choked flow past the butterfly delivers 0.528 atm in the manifold https://en.wikipedia.org/wiki/Choked_flow Choked flow around a butterfly valve occurs at <30deg opening; fig5 https://www.valin.com/resources/blog/gas-flow-control-valves Providing the engine is powering the car then manifold depression will be near 0.5atm when butterfly is <30 deg open. This is the cruise condition. Manifold depression when accelarating will rise above 0.5 atm, but the bfly is no longer choked. On the over-run when the throttle no longer controls rpm manifold depression can be near vacuum. Mo
  17. throttle position is directly related to butterfly angle, and hence to manifold pressure, so it can do the same job of advancing the spark at cruise.
  18. Hi Tom, Sadly I wont be able to make it, the PD is not yet under control, but I'm working on it. Have a good weekend. Cheers, Peter
  19. slides 91 et seq describe acceleration charge ,the PI lean spike and pinking from fuel fractionation. Slide 100 is HSM's disy recurve and static retime to allow the PI to be set less rich without pinking on 95 RON.
  20. The butterfly edge port works when the butterfly is opened by 30deg or less, but not completely shut. The butterfly at these openings is dictating engine speed and it does that by limiting the mass air flow in the gap. The air flow is limited because its velocity is sonic, meaning it is at the speed of sound so cannot move faster. The pressure in the a manifold needed to induce sonic air flow is half atmospheric, and that is the pressure that is found at the butterly edge in sonic flow. Sonic flow is also known as "choked" flow. When the buttterly is fully closed and the engine is in th
  21. The lack of acceleration charge in the PI leads to a lean spike and fuel fractionation in the inlet manifold such that, if run weak at cruise, the mixture upon wotting the throttle becomes briefly very low octane. That pulse of lean, low-RON mixture detonates and the engine rattles its pistons (pinks). Details here:https://supertrarged.wordpress.com/2013/06/12/the-lucas-pi-lean-spike/ Peter
  22. The reason for having vac advance at cruise ( hence the butterly edge take-off to the capsule) is to allow longer combustion time for lean cruise mixtures. This applies to most engines but not to the PI. The PI does not run lean at cruise in order to avoid pinking when the throttle is floored. The PI lacks an accelration charge device so has to be run rich even at cruise. If it is set lean at cruise there will be a "lean spike" when flooring the throttle and the pistons will rattle from detonation. SO the PI lacks acceleration charge, the cruise mixture is rich and that in turn means that vac
  23. My contribution to the play list. Should mystify the MG crowd !
  24. check the rubber joint between the lever arm and drop link, another known failure point.
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