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Everything posted by SuperDave

  1. One of the ugliest jobs I've done while stripping down an old 240Z has been removing the tar-like insulation that covers much of the interior floorboards and transmission tunnel. I have done it by using aircraft paint stripper, but this was a big mess. It softened up the tar, but made it flow into low spots. Once I had most of it removed with a paint scraper, I had to use a wire wheel and more paint stripper to get the last of it off. Some have suggested using heat, but I'd think this would also be a mess. There must be a better way. Actually, I found that with no chemicals at all, some of the insulation will come off quite easily. Just get the corner of a paint scraper under it and it flakes right up and breaks off. That's the good news. The bad news is that, unfortunately, these pieces come off easily because of what's underneath--rust! The insulation that covers clean metal doesn't want to budge. A few years ago, a fellow racer had said that dry ice was the best way to clean off this insulation. I saw it mentioned a couple of other places on the internet, but I couldn't find any articles about it. Armed with just a few instructions of how to do it, I decided to give it a try. I would try to use dry ice to remove the insulation tar in the rear hatch/ trunk area of the old 240Z. Getting the dry ice was easier than I thought. My local Kroger stocks it for 99-cents a pound. They broke open a ten pound bag to sell me 5 pounds. I brought it home and tried to break it up into as small chunks as I could. Then I simply spread it on top of the insulation tar. All the areas I treated were level. I don't know what is the best way to apply the dry ice to vertical areas like a transmission tunnel. I got a really good feeling about this process when, before I was finished spreading the dry ice, I could hear cracking sounds where the dry ice had been sitting for a few minutes. Due to the cold, the tar must have been shrinking faster than the metal and finally becoming separated from it! Once I had spread out the dry ice as best I could and broken it into as small chunks as seemed reasonable, I went inside to watch the finish of the Daytona 500 and to eat supper. I came out about two hours later. All the dry ice had melted (had become CO2 gas and sunk invisibly to the floor and out of the garage). I started attacking with my paint scraper. Now, with minimal effort, chucks of the insulation as big as 3-by-9-inchs broke right off. In just a couple of minutes I had removed almost all of the insulation tar. The bad news is that I found some really nasty rusty areas that I wasn't aware of. But they will be fairly easily repaired. I'm glad I know about them. I did not try one technique that I had read about elsewhere--to use a hammer to strike the insulation. It is supposed to just shatter like glass. I was afraid this would leave dents in the underlying metal. And, if I remember it correctly, you're supposed to strike it when it's still cold (and mine wasn't really dry-ice-cold when I tried to remove it). I didn't get every bit of the insulation. I think there were some spots where I didn't spread the dry ice thoroughly enough, so I guess the insulation didn't get cold enough. So it looks like I'll go back in a few days and repeat the process on those spots. This was an incredibly effective and simple process and I will highly recommend it to anyone who wants to remove this material from any type of vehicle. It didn't involve any nasty chemicals, and didn't leave anything to clean up. Obviously there are precautions to take--I used leather gloves to handle the ice. It gives off CO2 gas, so make sure you have some fresh air to breathe. Other precautions will usually be listed on the package of your dry ice.
  2. There's one in every bunch. Ever heard of the Grassroots Motorsports $2000 challenge?
  3. Thanks, but remember I'm trying to do this cheap. I'm trying to find something in a junk yard that approximates my needs. I'm assuming that getting custom springs made will cost just as much as the coil-over kits.
  4. OK, first, let's just get this out of the way: Everyone repeat after me. "If you don't want to spend the money, you have no business racing." Right. I don't want to spend four figures on suspension if I can avoid it. I'd like to find a way to get springs in the 400-350 pound range and stay with the stock struts and mounts. By playing with the spring rate calculator at http://www.proshocks.com/calcs/coilsprate.htm, it seems that I only need slightly thicker springs. 0.637" in the front would give me 400# and 0.618 in the rear would give me 350#. Compare that to the stock spring thicknesses of about 0.417" and 0.448" Great. Actually, if you got springs of about the same length as the Zed and with 10 coils, you might want to start with just 0.605" in the front and 0.588" in the rear and cut two coils off to lower the car. Now, where to find these springs? I read somewhere that the Jeep Grand Cherokee uses 4.5" springs like the Zed, but I haven't been able to verify that. And, of course, I have no idea what the rates are going to be for that vehicle. Any ideas? (Other than putting $1500 on the credit card for coilovers and one of the admittedly nice kits.)
  5. Not that I'm as expert as the others who have replied, but (when has that stopped me before)... Since you already have 350# springs on the front, and stiffer rear springs is one of the things that will help understeer, 285# springs would get you to SpudZ's 350-285 ARRC-winning spring rates. You might think about getting some of the eccentric rear control arm bushings that would let you adjust your rear toe-in, which could also help your back end turn some. PS - I'm about to get ready to prep and paint my ITS 240Z project and I'm thinking about painting it LIME GREEN much like yours.
  6. I'm not writing this to say you're wrong, but I went out and measured the springs on my '72 240Z and used the calculator at http://www.proshocks.com/calcs/coilsprate.htm to callculate the spring rates: LF: 0.4174" (thickness) x 4.5" (outside diameter) x 10 (active coils) = 62.7# RF: 0.4167" x 4.5" x 10 = 62.2# LR: 0.4481" x 4.5" x 10 = 85.2# RR: 0.4555" x 4.5" x 10 = 91.4# I had read somewhere that the left front is a little longer than the right front, but that shouldn't affect the rates, just the ride height I guess. FWIW, I have a set of 2" lowering springs on my old 260Z that's currently up on blocks at mom's. I'll measure them this weekend and let you know.
  7. SuperDave

    z bodies

    If the yellow turn signal lamps are on the corners below the bumper, same as a 240Z, then you have an early 74. If the turn signal lamps are up in the radiator opening like a 280Z's, you have a late 74.
  8. Sorry, mate (Are Yanks allowed to say that?). I'm pretty sure you'll have to pull the stub axles out--or at least part of the way out. I did this recently and the only way to go is to use a shop press--don't bother trying to bang on them.
  9. Thanks for the input. This sounds just a bit more complicated than I want to try. Especially the heating up and cooling down stuff. Also, I noticed, when getting an emissions test last week, that my local full-service gas station had a shop press. I toyed with the idea of taking them to these guys, who are friendly but I don't know how expert they are. So for this job I will stick with my trusted and proven professionals and make the 15 minute drive a lunch to drop off and pick up the pistons/pins/rods from my machine shop. Fortunately, I have a lot of time.
  10. I've rebuilt Z engines a couple of times now. I have a new set of pistons and am about to begin prepping, polishing, and balancing the various parts. When it's time to press pistons back onto the rods, I've always taken them to a machine shop to get the job done. I'm thinking about doing this myself this time. I have access to a shop press, but I don't know much about what tricks might be involved in pressing the pins into the pistons. How many of you have done this step? How many of you have screwed up this step? Dave
  11. Thanks for the info. White powderly finish? Hmmm. Maybe there is a final bath they give it. Or maybe they blast it with baking soda or something. Would you care to TASTE your car and give me a report?
  12. When I finish de-rusting my pieces and parts, I always have to clean them off with a soapy brush, dry them, and run a wire brush over them. The electrolytic process leaves a black substance that will turn to rust if you don't clean it off. I was wondering what, if anything, they used on your complete car to clean it up. Below is one of my latest pieces (after I cleaned it up and ready for a coat of primer), a rear control arm. <br> <img src="http://www.davesweb.com/houndawg/images/P1030675_640x480.jpg" width="640" height="480">
  13. I can't believe I didn't think of using a drum! That should de-rust your part on all sides at once! Have you eaten through a drum yet? You should eventually. Can you post some pictures?
  14. This weekend I saw a high school classmate of mine who has a 280Z that he has owned for 20 years and 5 of his 7 children have used as a daily driver. He told me the car has 650,000 miles on it with only one valve job in its history. Simply amazing! Can anyone top that?
  15. Thanks for sharing your dip results. It is simply astounding! I am insanely jealous.
  16. I finally got my stub axles removed. I took them to my Uncle's shop where he has an old homemade shop press. The thing is really strong--they work on bulldozers, skidders, and earth movers--really big stuff. So I don't know how many tons this thing would be rated for--I'd guess 20 tons or more. He's 77 and doesn't do much these days, so he didn't have a decent jack and I had to rig up my own floor jack rated at 6 tons to use with it. Using this press and this jack, the axles pressed out EASY! The first came out almost as soon as the jack put any pressure at all on it. The other was a little more stubborn, but the first pull I made using a cheater bar on the jack popped it right out. Based on this experience, I'd advise against hammering on these things. Banging and banging, even when applying heat, just doesn't apply the right kind of pressure that will get these stub axles out. A shop press is definitely the way to go.
  17. I can understand how tricky it is to put the new clip on, but I can't see how a frame can warp when cutting it out? Have you done this?
  18. I have 2 240's and one 260. Each one has her unique problems. 2ed #1 is pretty straight but is well-rusted underneath (I bought it for $150 for the carbs and the windshield, but she's been good for many other parts). Zed #2 has only minor rust and is very straight from the front compression rod mounts back, but she has had damage to her nose. I'll spare you the details, but she's crooked. A frame shop has obviously worked on her but couldn't get her perfect. I think she's close enough that she's driveable, but it's possible she will be tough to align and set up properly. With the exception of her warped front, Zed #2 is clearly the best of the two. This is not a restoration, but an ITS race car project. So I'm considering cutting off her front clip and replacing it with the front clip from Zed #1. I've found several articles on the net where people have done this on other cars. Are there any resources on the net about the best way to do this for a Zed? Have any of you done this? I figure I can do the cutting, the prep, tack weld it in place, then take it to a pro to do the rest of the welding. I know this is major surgery and I want to fully research it before I commit. Thanks, Dave
  19. That's pretty much my story exactly. I've run ITS Z mostly in Solo I, I haven't had the level of preparation ($$$) for success road racing. The last time I raced was three weeks before my first child was born--nearly 7 years ago. But I'll be back someday. I am building a new 240. I found a high-compression E88 head that John Williams told me he'd give me three E31's for if I could find one. Do you think I'm trading? No way! Even though J.W. is a super nice guy who has gone out of his way to help me in the past. But there have been set-backs in my project. I'll post in a week or so about the latest set-back.
  20. I have it, and have read and re-read sections of it. It's pretty clear about basic prep you need to do for a hi-performance engine. It doesn't keep me from occassionally doing stupid stuff... Dave
  21. Thanks Phred. Not what I wanted to hear, but I'm sure it's valuable info. I have not had the crank balanced yet. I think I'll take it to the machine shop and get their opinion. No more whacking on it for me!
  22. Very well put. I appreciate it that you didn't lump me in there with Robin Miller. I, of all people, shouldn't be throwing stones. I have a race record that is as dismal as it gets. I've stood on the pit lane fence as my co-driver made laps with a fried clutch and heard the snickers from the others on pit lane. Your defense of Vitolo comes across as sincere and it humbles me. I probably would not make the personal sacrifices Vitolo has made for a shot at Indy Cars. And even if I had the money (or could borrow or otherwise scrape up the money), I possibly don't have nearly the talent to avoid catastrophic embarassment. We all should try to remember how damn difficult racing is (even at amateur levels) and cut some slack when we sit in the stands (or on our butt in front of the tube) and see someone struggling. After all, they are out there on the track putting it on the line, and we are not.
  23. My Zed ITS project inches along. Tonight, during the current lull in my paint prep work, I measured the runout in my newly-polished crankshaft. I rolled out the block in its engine stand, flipped it upside down, laid bearings in the front and back, applied lube, and carefully laid the crankshaft in. I got out my new dial indicator and magnetic base and, after a bit of fumbling figuring out how to set it up, measured the runout in the center journal of the crankshaft: .006 in. The Honsowetz book "How to Modify Your Nissan & Datsun OHC Engine" says the maximum runout (or warp) should be .001 in. Question 1: Is .006 really a problem or just not optimal? I will be pushing this engine--I'm building a low-budget SCCA ITS racer for Solo I and occassional (in my dreams) road racing. Question 2: How do you straighten a crankshaft? The Honsowetz book says: "Don't try this, but crank is straightened by striking crank with a blunt chisel and hammer." Actually, I did pull the crank out, set it on two 2x4's, rotated it so the high point was facing up, and gave it a few hard whacks with a rubber mallet. And when I measured it again, the runout was down to .005 in! I did it again, and it didn't make any difference. I have done a web search and saw one reference to a method that uses a hydraulic jack somehow. I imagine machine shops have special tools for crank straightening, or do they just whack it and measure? Suggestions from you experts are welcome! I'll try what you suggest (if it sounds within my capabilities) and report back with some pictures. Dave
  24. I'm many months away from installing the rear sway bar. Right now it's stashed up in the rafters of the garage. At some point I'll pull it down, actually look at the instructions :stupid: and see what I've got and what I'll need.
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