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Michael

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Everything posted by Michael

  1. Update on the bent strut situation - Denny and I looked at several sets of front struts from parts cars. All of them had the asymmetry that I mentioned in my first post in this thread, though one of the non-parts cars looked to be symmetric, from the symmetric spacing between the widest part of the tire and the nearest point on the spring coils. My impression is that the tolerances on the steering angle of the McPherson struts used on Z’s is in general shabby – far worse than what’s allowable in the specs. By the way, from what I have been able to discern, there is no built-in provision fo
  2. The strut housings on two corners of my ’78 280Z’s suspension are misaligned relative to the spindle castings. That is, the projected angle between the strut centerline and the plane of the brake rotor is off by about 2 degrees from the specified angle (~14 degrees vs. ~12 degrees). The strut housings are not bent; they just meets the spindle castings at the wrong angle. This is at the driver’s-side front wheel, and the passenger’s side rear wheel. The result is an incorrect camber at those two locations. Neither the unibody nor the various suspension linkages are at fault. I have
  3. oops, first paragraph above - I meant displacement and velocity. late at night...
  4. Dan, Some time ago, I derived an alternative and somewhat convoluted formulation of the piston motion equations, which give the answers identical to yours for the speed and velocity. The acceleration answer for some reason differs by a constant multiple of exactly 6, which is almost certainly an error on my part (when multiplied by 6 and plotted vs. crank angle, our answers coincide). So my point is, your formulas make sense, and you did not make an error in typing. For typical rod/stroke ratios, piston peak velocity indeed occurs at around 75 deg ATDC (and again at 285 deg); f
  5. My story - Car $600 Roll cage $2500 Cutting up the sheet metal (labor) $1500 Engine mounts, frame mods (labor) $500 Exhaust (mostly labor) $300 Misc. plumbing $200 Engine core $850 Transmission $750 Bellhousing $250 Clutch -related stuff $500 Flywheel $300 Intake, carb, headers $500 Radiator and fan $400 Driveshaft $100 Small parts (add up!) $500 Shipping cross-country $850 Seat and cover $200 Fuel cell $200 Cam kit $350 That'
  6. SuperDave, RPMS, BLKMGK and others got it exactly right! To paraphrase a famous aria in a famous opera: "Love is like an ill-behaved child; it never does what it is told. Look for it, and you will never find it; don't look, and there it is!" utvolman, you and I are in a similar position: small, backward town inhabited exclusively by married people. I'm 29, and everyone at work is the typical Midwestern upstanding husband-and-father. But that's typical in engineering. And it's also typical that good jobs are located in boring places. What is surprising, both in your case and in mine,
  7. At this point we can observe that the remaining justification for suggesting that long-stroke engines have inferior rev performance, is that subject to the ubiquitous "all else being equal", the long-stroke setup will have a higher moment of inertia, implying that it would take longer to spool up. However, there is a straightforward (but expensive) remedy: use lightened components; a lighter flywheel, lightened crank, compact harmonic damper. Considering the costs of getting back the horsepower lost when losing displacement to destroking, this is a reasonable option. When I first wrot
  8. Just out of curiosity, what's inside the CFD code that runs "very fast" on a PC? If it's a panel method (vortex and source distribution, with flow-tangency boundary condition on each panel - and possibly vortex particles ejected at specific points in each time step, to simulate the "wake"), I would have to be skeptical. For an example of a state-of-the-art family of inviscid codes (tuned to mimic viscous effects), check out www.consultingaviation.com, or send them e-mail at cascd@mindspring.com – but please, don't mention my name. An erroneous answer is WORSE than a wild guess. A “b
  9. I was amazed how tight that Barracuda's engine bay is! The inner fenders extend so far inboard, that even the stock (or stock-appearing) exhaust is a tight fit - and that does not look like a wide engine. How did people ever shove a 426 Hemi in there? If a Crysler big block can be made to fit into the Barracuda, for sure it will fit in the Z.
  10. Comparing a completely bare 240Z shell to a completely bare 280Z shell (no sound deadener, no glass, no rubber, no doors/hatch/etc., and of course no mechanicals - nothing that doesn't unbolt or scrape off or unplug – the difference is or the order of 50 lbs. The 280 has longer and stronger frame rails, frame reinforcements fore and aft for the bumper shocks, and slight differences in the transmission tunnel, the door hinge mounts, the radiator lower crossmember, the spare tire well, the framing just aft of the mustache bar mounts, and probably in other places in minor amounts. There is some
  11. The idea of a rigorous test of the Z in a wind tunnel comes up from time to time.... I think that this would be nice, but prohibitively expensive. It’s not just a matter of renting tunnel time. You would have to build and instrument the model, figure out how to spin the wheels (pretty important), how to run the ground belt (very important), how to attach the various removable components (air dams, side skirts, spoilers,…). Figure maybe $300,000 for a decent model, $1M for a short test and maybe $10M for a serious test with multiple entries (pressure-sensitive paint, probe-rake traverse and
  12. Terry, Like your friend mentioned – what you saw was the footprint of a shock wave on the wing upper surface. I wish I got to this thread sooner; but at the present point, my post will just be review. In going over the front of the airfoil, the air accelerates to speeds significantly greater than the speed relative to the airplane itself. If the airplane is flying at, say 550 mph (well below Mach 1.0), there will probably be small regions over the wing upper surface where locally the flow is supersonic. Further aft on the wing, the pressure conditions are such that supersonic
  13. I want to second the call for “school first, finances second, hobbies third” – but keep in mind that your $40K will not necessarily make you a millionaire, even if you have decades and decades to wait, and “invest wisely”. Look at what happened in the stock market in the past 2 years. And don’t rush into buying that house, either. Houses have a nasty habit of declining in price, just after you buy them…. If you’re a mechanic, don’t hesitate to buy a cheapo stock 240Z. Drive it, maintain it, get used to it – then modify it. The point, I think, can be stated thus: planning ahead
  14. My (admittedly biased!) views on Ohio.... I moved to Ohio in the spring of 2000, due to a compulsory job change (Wright-Patterson AFB). Were it not for that, I would never have moved here. My reasons? 1. weather: 90’s in the summer, way way below freezing in the winter. Long summer, long winter, no transitional seasons, always humid. I have lived in Michigan, Northern Virginia, Los Angeles, and New York City; all of these places have better weather, in my opinion. 2. taxes: not as high as New York or California, but certainly higher than average. State income tax is mo
  15. The 7-degree thing is true. It’s an empirical fact, and not the result of fancy calculation. Separation of the boundary layer is a response to an adverse pressure gradient. If you do the math, trying to solve for an attached flow, you would find that for sufficiently high adverse pressure gradient, the attached-flow solution is no longer possible. Basically, it’s like trying to drive uphill – if the slope gets too high, eventually you lose traction and roll back downhill. It so happens that 7 degrees corresponds to a particular pressure gradient, which is the threshold at which a conventi
  16. Leaning toward a solid flat-tappet cam for the 454 in my 280Z, I have found that solid-cam options in moderate lift/duration ratings are limited. For Chevy big blocks, cams with less than 250 degrees duration (at 0.050”) and/or less than 0.550” lift are almost exclusively hydraulic, unless they’re muscle-car restoration cams, in which case they have healthy duration but comparatively low lift. One exception is Comp Cams’ “Magnum 270S”, which is 224/224 @ 0.050” and 0.530/0.530 lift. Now then, without resorting to the usual discussion of “what do you want to do with the car” [answer: I haven
  17. My car isn’t what one might called “finished” either; currently it lacks an engine, and has a strange suspension alignment problem. Nothing that can’t be fixed – but the fixing is the difference between running car and garage queen. But it is possible to sit in the driver’s seat and make engine noises while some one else pushes the car. I think there’s a lot of “moral support” value from face-to-face meetings between HybridZ people, even if the cars aren’t finished – or for that matter, not even started yet. If any of you local guys want to get together, I can be reached at ol_70@ho
  18. I’ve noticed that there are at least 3-4 folks on this list who reside in the North Kentucky – East Indiana – West Ohio – Columbus region. I’m south-east of Dayton, near the halfway point on I-71 between Cincinnati and Columbus. And I was wondering if we might consider a regional HybridZ meet, or perhaps just take a drive every now and then to look at who’s building what. I moved to this area about two years ago, in a forced career-related move. Every since I’ve been trying to make the best of things, often haphazardly. By now it’s finally time to meet by Z-neighbors!
  19. I have nearly the same situation as James: no wife or kids; a decent income, a house, and a Z that mostly just sits there. The sad part is that I bought a house primarily in order to be able to work on the Z – to have a big garage, to be away from neighbors who might get upset by electric grinders buzzing at night, to have a place to spread out my tools. But instead of working on the Z, I’m working on the house, fretting over the stock market, vegetating at work, and pinching every penny.... When I was in grad school, worrying about passing candidacy exams, building my laboratory setu
  20. I don’t rant too often, but after today’s financial news I can’t contain the impulse.... To all the reasons that folks lose the opportunity to build their V8 Z’s – divorce, poor health, job loss,... may I add losing one’s life savings in the stock market? This market is really going beyond the ridiculous. It seems to me that we have the dubious privilege of living through the greatest financial collapse in human history. The wealth of a generation, down the toilet. Is there anyone on this board old enough to remember the 1920’s? Anyone? Anyone’s parents, maybe? Please, please tel
  21. Pete- I gotta chime in with my congratulations! I've known you and your car for less than a third of the time that it took to build it, but even over that time I have been deeply impressed with your engineering and craftsmanship. Being picky and meticulous is unfortunately something that pays off only at the end. During the journey, it can attract doubt and loss of confidence. But now that the next phase of your journey will be in the company of a running beautiful V8Z, the rest of us can only say one thing - you done good, man!
  22. Jonathan, Let me make some “do as I say, not as I did” assertions.... There are some excellent deals of V8 Z’s out there, but from my experience, they are rare. Before I moved to Ohio, I spent about 5 years in LA. Every week I would look for Z’s in the Recycler. Typically, there would be at least one V8 conversion for sale every week. And typically, every one of them would be an abandoned project, or a “running” conversion that runs even worse than stock. One time I drove a "Nordskog" conversion that was for sale - the poor thing accelerated worse than my Corolla, and the brak
  23. Of all the big block choices out there, probably the Chevy BBC is the most natural choice (for reasons similar to why the small block Chevy is the most common small block to use). As Brad Barkley, Ron Jones and a handful of others (I believe there are about 5 big block Z's on HybridZ) can attest, the romance of the big block is hard to resist. They do fit - but not without some very clever metal work. You will almost certainly have to dispense with the mounting of the engine from the steering crossmember (instead weld mounting pads to the frame rails), and would need to notch the frame rail
  24. I have a roll cage somewhat similar to the one featured in this thread, so I thought I’d comment on some issues…. The X-bars in the car featured above actually tie into the unibody at all four corners of the "X"; I refer in particular to (1) the areas just above and aft of the upper hinges of the doors, and (2) the “corners” of the unibody where a B-pillar would normally be (the latter are tied together by the horizontal bar behind the seats). The continuation of the tubes forward of the firewall is unclear, but they look like "Monte Carlo" bars triangulating the front strut towers. Wi
  25. Let me add to the chorus recommending that you consult the JTR book and get a feel for the issues involved in installing the small block Chevy, regardless of your eventual choice. However, I would like to depart from the chorus in this regard: whereas the Chevy swap is probably the better choice from the point of view of upgradability and maximum performance, the Ford 302 swap might make for a better "sorta-stock" hybrid. The reason is that the Ford engine is considerably smaller and lighter. The T5 transmission and the stock clutch assembly should do just fine in the Z (not so for a
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