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drdoom

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drdoom last won the day on January 14

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About drdoom

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  • Name
    Steve
  • Car
    79 Esprit S2 7807/0100S
  • Modifications
    Total restoration grinding along.
  • Location
    Vancouver

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  1. Agree with Andy on this, and would add that oil surge control was found to be in order as well. The 912 brought a redeveloped sump with radial baffle, in addition to the sturdier main bearing panel. Early Esprit must be very carefully monitored if used to their limits, as many an owner knocked out big-end bearings due to oil feed issues. My S2 will be built with a dry sump I recovered from an early Turbo write-off. Cheers
  2. Good to know the operational details, Fabian. Oil pressure figures look entirely fine. No less a figure than A.C. Rudd, guest speaking for the benefit of our local Club in '86, offered the design criteria at 10psi per 1000RPM to a happy minimum of 45psi hot. No issues with somewhat higher pressures up to 65 psi, but no more than that to be beneficial. 4 months of operation with notable presence of particles or beads in the oil would account for the scoring, can't imagine what else could be the cause of that. Visible scoring is localized and association with anything further is speculative, whereas absolute wear must be confirmed by measurement Perhaps the fracture in that tappet was coincident with a score line, this is a known mode of failure in a brittle component. That the tappet broke is certain and indicative of brittleness. Well aged cast iron in question by various accounts. For there to have been sufficient wear in the tappet - bore area beggars belief and would have raised quite an audible ruckus, one would think. Get those measurements in hand and then consider the likelihood. There is always the option of presenting the tappet remnants to a materials analysis professional for expert evaluation, likely at quite reasonable cost. In summary - scoring is due to oil contaminant(s); PRV stuck due to same; tappet failure yet TBD pending measurements / expert evaluation but brittleness seems unavoidably linked. I do not expect proper steel would have failed in this situation, scored or not. Ultimately the stuck PRV and tappet may or may not be linked by way of the contaminant(s), scoring conclusively points to contaminant(s) and late arriving oil pressure is absolved of blame. The tappet failure has yet to be shown as other than coincidental.
  3. Well for how long was the engine run in this state of contamination? Not long enough to have generated broadly distributed wear, surely. The bits were not found to have been in a deteriorated state when assembled were they? Let's separate the certain from the uncertain, so a failed tappet and stuck PRV, score markings on the oily bits, and a long time getting pressure upon start-up. Tappet and scoring correlate marginally at best, tappet and cam/housing issues correlate certainly. Stuck PRV = absent oil pressure but when the car was motored about eventually you had pressure on the gauge, correct? If so then oil related wear is not indicated unless you were truly pounding on the thing. Measure these various components carefully before firming up your hypothesis. I'm leery of throwing paint around the oiled areas, if that's what you have in mind. Get the innards reasonably clean before assembly and then responsible maintenance takes care of the engine going forward. For a nicely presented engine exterior I believe soda blasting is quite effective on alloys of all sorts and should not have the peril inherent with stray glass beads. On wear versus oil pressure again I advise caution in that line of thought. Any number of early Esprit lost big-end bearings in the course of spirited driving due to several factors inherent in the car/engine, with the actual dynamic amounting to an unwanted gulp of air pumped across the bearings' surfaces while under load, at high revs. Straightforward failure, pointing the way to rational steps to mitigate in future. On the other hand we have my BMW saga, described earlier and one more I'll offer as instructive. One of the most seasoned local campaigners knocked a big-end out in the course of hillclimb competition, hours inland of here, then drove the unrepaired car 250 miles home without incurring damage to the crank journals. How so? It was a Seven, so very lightweight, the Crossflow has large bearing area dimensions, the crankcase was re-filled with neat STP Oil Additive, and of course he pedal'd the thing gingerly. FWIW, and amusing at least.
  4. The method whereby the oil pump is packed with petroleum jelly ( eg: Vaseline ) seems entirely sound. Should utterly seal the rotor-annulus clearances ensuring immediate pumping efficiency upon turnover. The stuff will dissolve in the oil rapidly and harmlessly, the initial seal improvement should enhance draw from the sump to complete the priming.
  5. To expand on the basic premise, beads so embedded will work loose at times and circulate throughout the motor. In regard to the bottom end the piston skirts are alloy and any particles which become lodged in them would be expected to score the bores, presuming the basic concept to be sound. You have headed off such grief rather early and it will be interesting to see how measures underway to mitigate prove out over time. I suggest you'll want to have the oil sampled once again after some extended run time and heat cycles.
  6. David, What has been your result in terms of the sound deadening efforts?
  7. Modality is that the beads embed in comparatively soft alloy - the cam carriers for one good example - then work to score the iron or steel parts obliged to run against them. Diabolical situation this
  8. I would not get overly wound up with concern for wear of the oil pump in the conventional sense as that is not something I have ever heard or read of in my many years in the hobby. I regularly socialize with senior mechanics who share various accounts of noteworthy engine and vehicle troubles, the only one pertaining to oil pump was as victim in the KIA/Hyundai engine failure fiasco unfolding in recent years. Do go ahead with checking the pump nonetheless as it's a simple thing, remember my earlier points regarding clearances within, if you will. The markings on parts revealed in the posted pics are not those of simple, conventional wear, rather they are witness to hard particles having circulated in the oil system. To William's account of the Alfa cam cover piece I say good luck to any who think laying on a sealant to the underside of said cover will endure. Not on any engine I'd be responsible for. Cheers
  9. Yup, the S4/V-8 parts/service manual seems to have been Lotus' culminating effort to compile everything they had from the Turbo forward into one great resource. I have reviewed my PDF many times in regards to one thing or another and find it to be my only guiding material for the dry sump system.
  10. If the pump is within spec regarding clearances, oil spec is reasonable then flow rate will be as intended. Lotus knew bloody well what they were up to in designing this engine for the most part as the service record bears witness to. A stuck PRV is another matter and would be associated with your tardy oil supply. It is possible you had a tappet fail coincidentally with the aforementioned, not necessarily by cause of it.
  11. Fabian, If I suggest any course of action it is in the best spirit of support and collaboration, and I'm confident that is true for Dave as well. Your enthusiasm is unsurpassed, inspiring to those of us plowing uphill on deep restorations. Garry Kemp is highly regarded, seems a valuable source for guidance as well as the components he distributes. No doubting your experience with absent oil pressure by any here, just cautionary words on what to take away from all this. The cam journals offer a considerable bearing area for their workload, the tappet/lobe interfaces are splash oiled as are the tappet/bore surfaces. If they have been wet they have been lubricated, for the most part. As to the oil pump, convention for checking condition is tip clearance between rotor and annulus (spelling?) and the side clearance between those and the housing in which they operate. Straightforward enough for checking, not a common point found to show wear in engines as they are lightly loaded and always operate in a lubricated state. FWIW. Press on mate.
  12. Simple challenge this time, I'm setting up seat mountings for my S2 and wish to optimize accommodation for my leg length. As I like to heel-toe for downshift matching it will be important that the pedals are well placed and it would be helpful to know what should be the length of travel of the throttle from rest to full throttle stop. Anyone care to measure it? Thanks
  13. Effect to geometry is determined by the plane in which relocation is performed. Outward re-positioning of the lower arm outer pivot will change the camber and its curve, kingpin inclination ( therefore steering offset, where the axis of steering meets pavement relative to tyre contact patch ) and bump-steer curve. An adjustment of toe obviously required as well. It's not something to pursue without some analysis, my back-yard engineer's thoughts offered free of charge.
  14. My term "unqualified" was perhaps not the best choice - my intent was to ask whether there were further details by which you would "qualify" the advice!! That has arrived with your comments just posted, thank you! Cheers
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