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PrecisionMike - The Lotus Forums #ForTheOwners Jump to content


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About PrecisionMike

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  • Birthday 30/11/1960

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    Esprit S2.2

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  1. Hi. I'm in the process of dimensional verification of my 912 build using Omega high compression pistons and would be very interested to know what exact piston you had. I'm measuring clearances of .0025 / .0033 which I feel are to small and are certainly smaller than the Omega recommended and am in the process of deciding what to do next. If you had the 9mega part number off the crown or a photo that yould be brilliant.
  2. Hi Giorgio, you mentioned a front crank cover modification.......what was the mod?
  3. Thankyou to all, job done! Very careful scraping with new razor blade after a soak in rust remover did the trick. With the blade held slightly away from the surface and pushed into the corner the fillet radius of rust and crude is gone. Thanks also due to PNM Engineering for advice!
  4. Spot on! As a mechanical engineer but not an expert in vibration and harmonics this is the root of the matter. There are two scenarios to design for a) the harmonics and resonance that may cause excessive deflection in belt runs and b) the loss of tension caused by counter clockwise rotation which can occur during engine switch off. Where there is a potential for resonance, dampers are usually employed and for the kick back situation I observe that many tensioners in high reving motorcycle engines often have a one way device which allows forward motion of the tensioner but limited reward motio
  5. Thanks, but I was rather refering to the mound of rust like crud that fills the corner radius in the counter bore where the liner sits. It is tough and looks like it needs a chisel and sandpaper which of course , though tempting would ruin the engine. ...I'm currently soaking it in rust remover which is slowly helping.
  6. pullies well, and feels sturdier than the others, but no guarantees! If the HTD pullies were priced better, I'd go with them, but this was an inexpensive upgrade for the time being. lists them under $60USD. Thanks you mean Nissan 200....I had a 300 zx twin turbo years ago (fantastic machine...some to rag stole it and burnt it) and that was a v6 with a single cambelt 6 yards long!
  7. Looks like a fantastic job. Do you have any tips for cleaning the liner seating area in the block.
  8. I have been considering this too but feel some small range of spring compliance would be beneficial in coping with thermal expansion and contraction. I will give the matter further thought and post my solution when ready.
  9. Hi, I've been thinking about such a mod..Some sort of threaded rod passing through the adjuster. How were you planning to do it? Excellent and thankyou Lovely looking engine !
  10. Please dont get me wrong, I love lotus and I've owned mine for thirty years....I'm nit sure lotus had a strategy for solving an early belt jump problem.....I think in the early days thet lurched through a field of iterations in hope that the "next mod" would fix it. I've worked on various high reving Ferrari, alfa and Landis all of whom use auto damped tensioners!! Who really knows?????? We need a direct line to CABC!
  11. Hi. I had understood that after 1986 / 7 the 900 series standardised on htd with fixed eccentric tensioner and not the auto tensioner?
  12. Thankyou for your response. I'll give the matter further thought. I'll try to get hold of Gates who make the belt !
  13. I'm building a 912 currently and have intention to use the htd drive system but I cant decide if I should revert to the fixed eccentric tensioner. I've run a 907 with a trapezoidal set up and auto tensioner for 36000 miles without issue. With the fixed eccentric tensioner I love the thought of simplicity but I'm not happy with the thought that thermal expansion simply results in increased tension. But with the auto tensioner which clearly accommodates thermal expansion and contraction, I hate the thought of induced belt slack when the engine kick back in the wrong direction a few degrees as ca
  14. Hi, I'm in the process of the same project. A point of clarification please. I had understood that the 912 valves had smaller dimples but the inlets in your photo appear to have large dimples suggesting they are from a 907. Was that intentional perhaps to tune compression ratio or am I incorrect?
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