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Everything posted by Michael

  1. Folks, OK, here it is - pictures of my car: http://members.home.net/pparaska/MichaelOlsZ.htm A big huge thanks to Pete Paraska for hosting my "web page"! I apologize for the sloppy photography - hopefully I'll have better images soon. The last photo sort-of shows how the engine is installed, but the rear 1/3rd of the engine sits under the windshield valence panel, obscuring the view. If you look closely, you can see the Griffin radiator angled forward. With the hood closed, the air cleaner just barely sticks out. Big blocks are tall. I had to either put up wi
  2. The best estimate that I have heard for fully dressed L28 (no transmission) is 425 lbs.
  3. Some more details... The battery is in the rear, next to where the fuel tank vapor canister normally sits. The radiator is a Griffin 28"x19" (frame rails notched to fit the wide radiator). Suspension is completely stock. The motor is all cast iron, except for block hugger headers and aluminum intake. For big blocks, aluminum heads are claimed to save 70 lbs. I looked at the GMPP aluminum heads - they are one of the options, along with Edelbrock and Brodix, among the oval port choices. Do any of the big block drivers have a particular recommendation?
  4. The transmission that I was talking about (Doug Nash 5-speed) was purchased used, with a claimed 20,000 miles on it. The application was in a V-12 Jaguar, and the seller claimed that he was selling it only because he upgraded to a six-speed Richmond (no overdrive in a Jaguar is even sillier than no overdrive in a Datsun). Anyway, what I bought almost certainly inferior to a brand new unit. But I only paid $750, with the shifter. The transmission also makes a dull "whirring" noise when going in reverse - and only in reverse.
  5. My understanding of the flow measurement techniques is that cylinder head flow numbers are always obtained from tests on a flow bench, never on a running engine. On the flow bench, the head is subjected to a fixed pressure drop. Generally that number is 28†of water, which corresponds to approximately 1.0 psi. Each port is tested individually. The valve is held open at a set opening height, and flow volume measurements are taken for a sequence of opening heights. Generally, the intake manifold and engine block are missing; they are “modeled†by plastic pieces which attempt to approxima
  6. Well, amidst the chaos of the apparently failed rod bearing, I got a chance to weigh the "set-back rat" on a set of four digital scales. Here are the numbers (all are in lbs): with no occupants: left front: 718 right front: 690 left rear: 643 right rear: 674 total: 2725 with the driver: 777 680 727 723 That comes out to about 51% front/49% rear. I was hoping for something like 47/53. However, the car came out 100-200 lbs lighter than I expected.
  7. whoops - the previous post got cut off. Anyway, after a few laps around the block, I noticed a loud and annoying knocking sound coming from the engine. It is proportionate to the rpm, but it is not constant. Rather, when the sound is loudest (at any given rpm), oil pressure appears to drop. Then the sound intensity ebbs, and oil pressure returns. While I have no tachometer (yet), I doubt that the engine ever saw above 3000 rpm. Trivial errors such as crossed plug wires and vibration of under-hood components were elliminated. Is this the tell-tale sound of a spun rod beari
  8. Yesterday I drove my '78 280z for the first time. It has a near-stock 454 big block engine and Doug Nash 5-speed transmission. With the stock tires, wheel spin is unavoidable in any gear. In traffic, the car is best driven by starting in 5th gear and never shifting. Maneuvering around the parking lot is possible in 1st gear, provided that the gas pedal is never touched and the clutch is feathered while the engine just idles.
  9. Well, I just drove my rat-powered 280Z for the first time (see post under "Chevy V8" topic for more details). The car has a Doug Nash 5-speed. Even after reworking the shift linkages and oiling the shifter mechanicals, the thing is still incredibly notchy to shift. It's so bad that more time is spent on the 1-2 shift than under power in 1st or 2nd gear. There is essentially no feel for neutral, and telling 3rd and 5th apart is very difficult. Fortunately, the engine has so much torque that with street tires, 3rd and 5th gears are indestinguishable. So, to anyone contemplating the Do
  10. I ended up going with a Simpson 5-point camlock harness, about $160 at Summit. It's a bulky setup, with the shoulder straps and waist straps 3" thick. Putting it on takes much, much longer than putting on a regular seat belt. But, with the camlock, it comes off very quickly - and this is certainly the most important consideration in a race-type situation.
  11. I'm the oddball here, but I thought I'd post anyway.... My "set back rat" Z has a 454 BB from a Suburban (1978). I installed a Comp Cams "Extreme Energy" hydraulic flat-tappet 218/224 (@0.050") .504/.510 lift, 110 degree lobe separation. It's relatively mild for an engine that big. But, with stock rockers, I'd run out of rocker slot gap with a larger lift cam. And the bone-stock heads are probably no good above 5000 rpm anyway. Now here's a question for the experts: to get heads with relatively small-area ports and small valves to breathe better in the midrange (I got the low e
  12. Pete, Actually, I think we're talking about the same thing. In particular, I'm referring to page 16-14 of the JTR book (6th printing). I wanted to get the largest backspacing possible, being fully aware that the tires will still stick out from the rear fenders, and that the fenders will have to be cut. That was for structural reasons, to keep the wheel's mounting face not too far inboard of the wheel centerplane. JTR says that coilovers increase room for additional backspacing in the front, but are of no help in the rear. I wanted to confirm their comments. The plan is to
  13. My guess is that the BMW Z8 guy’s comments about no aero testing were just bravado. At the very least, they must have done some kind of wind-induced NVH testing, to make sure that the playboy in the driver’s seat isn’t subjected to too much wind buffeting, and that his escort’s hair doesn’t get messed up. As for the headlight covers – all of the ones that I’ve seen follow the contour of the hood’s sharp front lip. Cosmetically, that makes sense, but I’m not impressed by the design. Jim Biondo’s fiberglass “front clip†looks like a very sensible route (does he h
  14. I would like to ask the complementary question: if the stock spring and strut assembly is retained, what does that do to the possible choices of wheels and tires? Or, phrased another way, is it true that in the rear, coilovers do not afford any greater tire clearance advantages? I would eventually like to run large diameter (28" or greater), large width slicks. The olny Z's that I've seen with such tires were back-halved. Any info would be greatly appreciated.
  15. The technique of taping tufts or strings to the surface of a body to get a sense of the flow around it, is a tried and true method. It tells if the flow is smoothly following the surface, or if it’s “separatedâ€, which generally (but not always) means low pressure. It also can give clues about flow reversal, such as in a large separation eddy or local backflow. Unfortunately, tuft flow visualization says nothing about how much air is flowing, how fast it’s flowing, etc. What makes engineering an effective cooling flow scheme difficult is that to do it right, other aspects of th
  16. I have a Doug Nash 5-speed (same as the Richmond 5-speed) behind the 454 big block in my '78 Z. The car is oh so close to actually running, but right now it's sitting in a parking lot. The transmission fits in the 280z tunnel without too many problems. There was actually room for a dual 2 1/2" exhaust. However, the shifter is DEFINITELY a problem. I had to cut a 5" hole in the driver's side of the transmission tunnel, and then fabricated a cylindrically-shaped "box" to accommodate the shifter. These externally shifted transmissions evidently all have that flaw. Also, as pointed out by
  17. This is not entirely on-topic, but for those of us that have already committed to a transmission, and have a 3.7 or 3.54 R200, there aren't many options left to reduce cruising rpms, other than to get taller rear tires. Wheels and tires come up for discussion all the time; normally the topic is how to get the widest tires possible, but still get them to fit with the stock Datsun sheet metal. My question is, what are the TALLEST tires that people have been running in the rear? For a first iteration, I'm considering pickup truck or full-size Detroit landyacht tires in something like 28"-
  18. I bought a 20 gallon aluminum "fuel cell" from Triangle Engineering about six months ago (via Summit). The welding is beautiful, but keep in mind that it's NOT a true fuel cell, because it has no fuel bladder inside - just foam. Also, the fuel filler cap is supposed to have what amounts to a check valve; it should vent air into the cell as fuel is depleted, but it should not vent fumes out of the cell. Well, I mounted the fuel cell inside the rear hatch area (no room under the floor due to center-mounted dual mufflers), and if I leave the windows rolled up overnight, in the morning t
  19. Well Pete, since you threw down the gauntlet... Gearing constrains how fast the car can go in principle, without exceeding the engine's power band. So let's assume that we have tall enough gears in the differential, and sufficiently many gears in the transmission, that any speed from 0 to 300 mph is allowable by a gearing/rpm calculator, like that web site that people have been referring to. So, what limits the top speed of the car? The balance between power available and power required. That's true for any vehicle, be it your bicycle or a jet airplane. Power = force*speed. On
  20. It will depend on the powerband of your engine, on the hi and torque levels, car weight, etc. (in other words, on the expected quarter mile time). Most likely, the 3.9 rear end will make hooking up off the line a problem, unless you run slicks. A lot of time is burned up in that first 60'. So, based on this reasoning alone, the 3.54 is probably the better choice.
  21. Pete, I'm going to say something that you probably don't want to hear: STICK WITH THE TREMEC!!! You've been working on your Z for how many years now? Probably your kids have no recollection of what life was like before that car went up on jackstands. I've never driven a Tremec either, but is the hearsay and bad reputation enough to justify scrapping a perfectly good setup, dumping $1500, and losing what may be several months time? I've also installed a transmission with a 3.27 1st gear, but mine doesn't even have overdrive - and I have a 3.7 R200, and - gas
  22. I think that for many of us, the main problem with switchng to a solid rear axle is cost and complexity of the operation - and not an aversion to the setup itself. Most of the engineering challanges encountered in our V8 conversion projects are a matter of how to construct something. The "design" aspect comes down to how to make things strong enough, to make everthing fit together and stay together. Changing suspensions, however, involves a conceptual design change, and that includes textbook calculations. In other words, you essentially have to know how to design cars from the ground up. An
  23. I second Mike KZ's comments. Regardless of the eventual details of your front suspension, you'll have to have something that spans wheel-to-wheel to accommodate the steering, and it would be great to get the crankshaft pulley behind that something. That makes working on the engine MUCH easier, not to mention the improvement in weight distribution. Will the windshield and A-pillars remain in the stock location? If so, you still have something like 10" of space to set back the firewall, before the distributor cap hits the front windshield lip. That's because of the awfully deep valence
  24. I suppose that like most upgrades, this one comes down to a matter of personal preference. About a year ago I was also thinking about an aluminum block - aluminum big block, that is. GM performance parts had reissued the much-vaunted ZL1 "aluminum cylinder case", and Merlin (World Products?) has a whole line of aluminum big and small blocks. The cheapest aluminum BB is around $4-5k; SB may be around $3K. Costs aside, one issue is how to mount the bearing caps. The GM LS1 is cross-bolted, which I was told works very well, although another chorus claims that LS1's are notorious for spinning
  25. Stay away from Supras! I used to own a '87 Supra turbo. The engine reputedly weighs more than a Chevy small block, and though the bottom end is truly stout, head gaskets blow very easily. The turbo is tame in stock form, and Supra tinkerers claim huge performance increases due to higher boost (the stock electronics and plumbing will allow up to 13 psi before fuel cutoff issues appear). BUT, we're still stuck with the low end torque issue. Turbo lag on these things is tremendous, and very frustrating off the line. Years ago, I thought of yanking the inline-6 in my Supra, and swappi
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