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Ironhead

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Everything posted by Ironhead

  1. Welding VBands and keeping them from distorting is actually slightly tricky. I assemble them, with the two flanges clamped together, before final welding. If you don't do this, and weld with much heat, the flanges can distort like a potato chip.
  2. When welding tubing...like an exhaust...you will find that nothing moves around much if your fitup is perfect or very good. I always face the ends of the tube on a disc sander, so that they fit together with no gap. If you do this you will get little or no movement when you final weld it. If your fitup is good you can "fusion" weld it together, with no filler, but I personally never do. I just feel better about the weld if I add some .035" or .045" filler when final welding. I realize a properly designed exhaust isn't under tremendous stress, and it's not like welding an airplane structure, but I always use a bit of filler regardless.
  3. You can do a few experiments on scrap pieces and it becomes pretty apparent that back-purging on tacks isn't really necessary. As long as the fit is decent and thus the tack is pretty quick, you won't see any significant "sugaring" on the back of the tack. But when fully welding all the seams, I think back-purging is critical and I never fail to do it. Again, experiment on scrap. You will see the porous gonad-looking growths that appear on the back of a stainless weld if you don't. Not only are these likely places for cracks to start, but if every seam is welded in this matter, it would be hugely detrimental to exhaust flow as well. There are occasional welds wherein it is either impossible or impractical to back purge. In those places I either use Solar Flux, or clamp a piece of aluminum on the back of the joint to serve as a heat sink/argon trap. If none of this is possible....I just grind off the sugaring when I am done welding.
  4. It is amazing, on track, how massive amounts of torque seem to minimize the effects of sloppy driving. I also have a BMW E30M3 track car, with an N/A four cylinder engine that has very little torque, and really only develops HP above 5000 RPM. It's a classic momentum car, in which you have to take turns at the absolute limit, keeping momentum up, particularly before the long straights. If you fail to do this your lap times plummet. The LS swapped Z is completely different. Any momentum lost is immediately regained with a stomp on the throttle, almost regardless of RPM. Obviously both cars take a great deal of concentration to drive at their individual limits, but just "going fast" is so much easier in the Z. I can just mosey through turns, nowhere near the limit, and still lap significantly faster than the BMW.
  5. There's no doubt an engine swap completely changes the character of the car. Mine has a 525 HP LS3, and it is more like a lighter, less refined Corvette than a Z car, honestly. Some might say I should have just bought a Corvette, but I have a method to my plan and I am happy with the outcome.
  6. I just wanted to say, this post made me LOL. I have wondered the same thing about the "hella flush" cars. I see so many on the 'net that cannot possible have any meaningful suspension travel. Not just Zs either, the RWB Porsches being the best example I can think of: https://fifteen52.com/blogs/52/27618305-rwb-x-fifteen52-porsche-911-993
  7. Looks like great work on a very "needy" shell. I was just trying to imagine, think how different our "hobby" would be if cars didn't rust. By different, I mean better.
  8. Just reading over your plans, and have to say I was getting a bit annoyed just hearing about how hesitant AME has been to convey information or "work with you" on anything custom regarding your project. It kind of gives me the impression that their chassis are intended for show car builds wherein they do little but provide the means for the completed project to roll on and off a trailer....
  9. I think the gearing/final drive is perfect for a track oriented car, not so much for street driving. In 6th gear at 75 MPH it is turning around 2700 RPM. I am only getting around 10 MPG street driving. The HP was alarming when I first drove the car, bit I have gotten used to it. The car puts power to the ground very well, amazingly well, actually. I can certainly break the tires loose, but only if I do it deliberately. Rear "R" compound 315 wide tires definitely do their job. I have no desire yet for more power, but I think the car could handle it fine. I have not weighed or corner balanced it. It could definitely be pretty heavy for a Z. I built it prioritizing strength/safety over light weight. Once I got the brakes dialed in, I think they are perfect. Except for the squealing. That is horrendous. Driving through my neighborhood I stop with the handbrake, just so my neighbors don't come after me with torches/pitchforks. For some reason just using the rear brakes kills the squeal.
  10. I used Lizard Skin sound deadener on the inside of the roof, but again, all it really does is get rid of the tin-can ringing effect. It doesn't deaden noise much beyond that. It's funny, I am using dual 3" exhaust and I don't consider the exhaust on the car to be particularly loud at all. The "noise" in the car is mostly coming from other places...suspension movement, road noise, and engine mechanical noise primarily. My exhaust does include a resonator and two large mufflers though. I wanted the dual 3" just in case down the road I decide to be an even bigger idiot and seek more engine power, the exhaust won't be a limiting factor. Regarding the 2.66 rack, that would be way too fast for my tastes, but then again I don't autox. If I did I would probably see it differently.
  11. Lock to lock is about two turns, but that doesn't mean much as I have rack stops in place to stop interference issues at full lock. I would say the steering rate is similar to a modern Vette or something along those lines. It still has plenty of lock to do a "U" turn on a fairly narrow street, but not enough for drifting for sure. Much of the harshness in my case comes from the fully Heim jointed suspension....and also very stiff springs. It handles great, but hates major bumps. When I hit a bump unexpectedly, it feels/sounds like I broke something....LOL. I also have very little in the car to absorb sound. The floor of the car has a coat of Lizard Skin, but honestly that really only takes away the "tin can" ringing...the car is still loud inside. I went dry sump because I have another track car, with a very sophisticated wet sump pan, and I still see the ******* oil pressure light come on during hard braking. It drives me crazy. The dry sump also greatly helps ground clearance of course, and I have read multiple accounts of wet sump LS motors having oiling issues on road courses. Dry sump is better in every way except cost. I think going with a custom chassis is a cool idea. Best of both words if you aren't concerned with "originality", which obviously I am not....
  12. The 2.09 is what I am using. Keep in mind my shorter than stock knuckles factor into it all too, but the combination feels really good to me. You will definitely need power steering, particularly if running wide tires, which I imagine you will. I would guestimate 1.75 is close to stock Datsun ratio. If your goal is primarily a street car, you definitely want to do a lot of things differently than I did. Mine can be driven on the street obviously, but it's all pretty harsh and kind of kicks my ass after an hour or so.
  13. Thanks for the kind remarks. I am not the least bit disappointed that there were a few issues to sort out once the car was running. Truth be told, there were far fewer than I expected. Also, the car has never actually "broke down", nor has anything failed in a catastrophic sense that damaged other components. I have been driving the car a great deal and honestly it has been pretty reliable. Regarding your questions: I went with the tandem master cylinders w/o power boost so I could use a balance bar to adjust front/rear bias from the driver's seat. It also makes it very easy to swap out master cylinders for different sizes to get a perfect balance of effort and front/rear bias. I did have to experiment with master cylinder sizing, pedal ratio, and most importantly pad compounds, to have what I considered "good" pedal pressure and acceptable cold braking. I settled on very aggressive pads (Carbotech XP20) and absolutely love them...great cold bite...zero fade....etc. The only downside is major squealing when light/moderate braking, like is common in street driving. I can live with that...as this is mostly a track car. After the fiddling, the brakes on this car are fantastic...I wouldn't change a thing. Well, I would like to have had ABS, but the costs and complexity of installing a motorsport ABS system were insane...no way I was going to do that. The electric power steering is sorted. I started with a Datsun Z specific kit that used a stock Datsun steering column. That was the setup that I found gave erratic boost, and didn't really seem to respond to the rheostat knob adjustments. Also, the steering column bearings were shot, and the column would clunk whenever I changed steering direction. The PS motor that came with this kit was from some weird Renault I believe. I started from scratch and built a new EPS setup using the Saturn motor and a Woodward steering column. It took a bit of fab work, but it works perfectly now. It uses a rheostat knob to adjust the amount of boost. I would recommend ordering the slowest steering ratio that Woodward sells...I can't remember the specific ratio. I am using the shortened Apex Engineered knuckles, and between those two factors, the steering is pretty quick, much quicker than stock Datsun. It is also far too heavy to even consider using without some sort of power steering, although the 275 wide front tires are definitely a factor there. Ignore the steering ratio I said I was using in the thread...I believe that was the "medium" Woodward ratio, which I have since ditched for the slowest one. The medium ratio was completely drivable with the EPS, but I just found it disconcertingly quick. I didn't like it. It was go-cart like.
  14. I too used this kit: https://www.ebay.com/itm/322668159056 It worked well, no complaints. I can't help you with the roller detent pin. You might have no choice but to have one machined.
  15. The Vintage Rubber front and rear windshield gaskets can (maybe) be made to work, but they are extremely difficult to install. At least they were on my car. After a huge struggle I got the rear one in place, but I can't even describe what an ordeal it was. In the front I wound up cracking the windshield trying to "persuade" the gasket into place. So I had professional installers come in from a place that specialized in vintage car window glass. They struggled with the gasket for over an hour and could not make it work. I finally gave in and had them use an OEM Nissan gasket ($$$) that I was going to sell because I figured I could use the Vintage Rubber gasket. The OEM one went in a breeze. I think the problem with the Vintage Rubber gaskets is just that they are slightly too stiff and the rubber is a bit too hard to work easily. I do realize, however that our choices are limited. I don't know what else to say though. I could not make the front one work nor could the pros.
  16. Great work! Just think how much more fun/simple/satisfying old cars would be to tinker with if it wasn't for rust: Either having to detect/access/repair rust or do things to prevent it.
  17. I used Trackspec vents on my build, not exactly the ones you mentioned, but I think they are all pretty similar. I think they are great. No complaints at all.
  18. I have a 260z, not a 280zx, but on my car at least I much prefer a larger diameter wheel, similar to stock. There are several 380mm wheels on the market, from OMP and MOMO at least. I don't know exactly what it is on these cars, as I am more used to wheels in the 330mm range. But I tried those on the Z and did not like them. Much better feeling of precise control with the larger wheel.
  19. That's a tough one. Based on what you have done, I would conclude the noise is coming from somewhere besides the diff, but I am sure you have already investigated that possibility? I know bad bearing howl can be quite difficult to pinpoint. Any chance you have a fried wheel bearing? Could the noise be from the transmission? Apologies if these are stupid questions, but it sounds like you have addressed potential diff problems four times over....
  20. I know this isn't what you asked, but for fender flares I would use rubber well nuts. https://www.mcmaster.com/well-nuts/ They seal the holes without damaging the paint, allow for a bit of misalignment (much more than rivet nuts), and IMHO are much easier to use. I have used a lot of rivet nuts in various applications where there is no better option, but find them pretty temperamental in the sense that they always like to spin and have to be drilled out and replaced. Well nuts also have the advantage, that in any sort of collision they will shear off rather than greatly damage the underlying bodywork.
  21. One of the things in my experience that makes older cars unreliable is corrosion in the electrical system, primarily the connectors. You can track down all sorts of elusive and intermittent electrical gremlins, only to find the corrosion was the issue. It is never ending, because once corrosion has begun, cleaning it off only seems to provide a temporary fix and it returns. I have found once you re-wire the car (assuming you do it "right") all the nagging glitches and issues disappear.
  22. I used a Tilton pedal box in mine. Hard to recommend this approach unless you have the dash area of the car pretty much completely dismantled. You are going to have to weld in structure/brackets to support pretty much any aftermarket pedal setup.
  23. I know what you are saying for sure....the inclination is to cut out as little metal as possible. But where there are pinholes, there will be pits, so the surrounding metal that is not pin-holed will be massively thinned and weakened from the corrosion.... Working on my shell, I found myself making larger and larger patches. It just seemed to work better than trying to fill pinholes or using a large number of smaller patches.
  24. I don't know what your skill level is at TIG welding, but if you can do what you propose, it would be a good repair. I can tell you that using TIG on the thin Datsun sheet metal....particularly when it is even thinner from corrosion, is very difficult. Even at 20 amps, burn through will happen extremely quickly. If you can pull it off, you are way more skilled than I am. I found the best way to remove pinholes was to cut out all the corroded metal and weld in a patch. But that's just me....
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