jmortensen

I bet your diff isn't worn out. I found out some interesting things about Nissan LSDs and advertised vs actual breakaway pressures: http://forums.hybridz.org/showthread.php?t=92629 As far as the howl goes I had mine rebuilt by a shop when I first got it about 8 years or so ago and they screwed it up 3 times before they got it right. What I'm saying here is there aren't too many shops that have dealt with the R series diffs before. Not like they're particularly hard to deal with, but they aren't the usual Ford 9" (which is really really easy). After I tore into it the last time to shim up the LSD I looked at the bearings, and I think I know what causes the noise. I believe that it is the ball bearing at the end of the pinion shaft, just inside the pinion seal that is the culprit. This bearing is the hardest to lubricate because it is the farthest from any of the gears, and the gears sling the oil. I had my old diff and my 200SX 4.11 diff to look at and BOTH of them had a noisy bearing there, and all the rest of the bearings were fine. You might want to see if you can pull that bearing yourself and check it. The hard part about getting to that bearing is that the pinion needs to be removed. The FSM says hit the pinion with a BFH and a brass drift. I had to press mine out. I whaled on it with the BFH and that sucker wouldn't budge. Got a press and had it out in 5 minutes. BTW shimming the diff up is pretty easy to do too if you wanted to give that a shot. Any questions I'd be happy to help.

Could be an out of balance driveshaft or it could be that the driveshaft angle is wrong. You can shim the transmission down to lower the angle on the front driveshaft U-joint to try and fix. You could probably also shim between the diff and its front mount to raise the nose of the diff. V8 guys deal with this issue all the time, so you might want to check hybridz.org if you can't figure it out. I'd start with the driveshaft itself though and see if it is out of balance first. There is also another thing called driveshaft phase, but I would doubt that this is your problem unless you had the driveshaft tube replaced for some reason or you're using a 2 piece driveshaft with a roadster transmission (both would be pretty unlikely). Basically the front and rear U-joint have to line up in a certain way or else it will vibrate. In 99.999% of cases on a Z you're using a factory one piece driveshaft so this isn't the problem.

When I went to move mine back I bought the later style link behind the diff that has the curve in it. After I did that I read on the net that you can move the diff back and still use the straight link behind the diff. Your experience would show otherwise... I moved the strap back by moving it back an inch also and attaching it by the front bolts on the strap mounts to the last 2 holes in the chassis. You have to grind a little bit to get it in that way (very minor grinding takes 2 minutes), and I ran mine for a couple years like that and had no trouble with the mounts coming loose or anything like that. I finally decided to get rid of the strap entirely, so next time my car drives it won't have a strap anymore. Search front diff mount and you'll see some very easy modifications are possible that eliminate the strap completely.

It's not true that they are bolt on. This was discussed on hybridz and my understanding is that they send out springs that are more than 500 in/lbs. Those are amazingly ridiculous spring rates for anything like a stock Z. You don't need dual springs to "reduce the common jumping noises" because jumping noises aren't common with coilovers. The real reason to use two springs is so that you can get a progressive spring rate. The thing is, if you want coilovers, you probably don't want progressive springs because they are more of a comfort thing than a racing thing. The product is not great. Avoid the dorifto mistakes of extremely stiff spring rates and useless helper springs and get your coilovers from Ground Control, or Modern Motorsports. Or if you want to save some money start looking for the parts individually from a circle track racing shop, like Pegasus or Behrents or Coleman Racing or Pit Stop USA. You can buy the springs, hats, threaded collars, etc cheaper through those types of places, although my understanding is that the Ground Control and Modern Motorsports stuff is the highest quality. I've had the GC stuff on my car for 8 years. Never had any jumping noises. Never needed double springs to "enforce" my car's handling either.

As I recall from my friend's diff (which I was looking at 10 years ago so memory is a bit fuzzy) the side shafts were the same. If they were different I'd imagine you would have noticed that the splines were different when you installed it, and it would have made a hellacious noise and stripped out the side gears when you first started to put power to the diff had they been wrong. It sounds like you're still searching for the cause of your chatter. I'd be willing to bet that $5 USD worth of additive will solve your chatter problem. I tried to look up that lube you're using. I couldn't find anything useful on the Castrol site, but Several other forums on the web had posts about needing additive with that particular lube, the last indicates that the manufacturer suggested a particular type of additive that he couldn't find. I think this suggests that Castrol thinks it needs the additives, but again all the additives are basically the same, so just get whichever one they stock at the auto parts store. Even if you use an "LSD" oil, if you have chatter the solution is to add MORE friction modifier until it goes away. When I used to sell diff parts we sold the Eaton posis with the upgraded springs and 22 plate steel clutch packs, and Auburn Gear Pro Posis. These particular LSDs are the most aggressive I've come across and had several hundred lbs of breakaway force, and sometimes the customers needed 3 bottles of the additive to get the thing to stop chattering. It's one of those things where you just keep adding it until you don't need anymore. Here are some of the threads I found online: http://www.ls1gto.com/forums/archive/index.php/f-28/t-35766 http://www.calaisturbo.com.au/showthread.php?t=60039 http://www.fordforums.com/archive/index.php/t-96058.html http://www.4wdaustralia.com.au/Forum/Archive/2005_3/23987.asp

As the others are saying it sounds like you're missing out on about 3 or 4K rpm worth of fun. Rev the wizz out of it. That's what Rebello built it for.

If he ran it before he would probably know if it was a locker, don't you think Ron? My friend had an R190 with a Detroit Locker in his 510. It was a whole different experience than an LSD. Really brutal when it ratcheted. I had never experienced a locker before I was in his car, and I literally thought the diff was going to be laying in the middle of the road when it started ratcheting. It was positively violent. I believe the Detroit Lockers were made for the H190, not the R190. The fact that they are the same leads me to believe that the H190 LSD would work as well. That kind of corresponds to John Coffey's recent finding that www.differentials.com and www.reiderracing.com have Power Brute (re-badged Nissan) LSDs currently availabe for the R190. So it would seem that the tough part would be finding a ring and pinion should one be needed down the line, and that part I do not think corresponds to the H190.

In the US the commonly available additives are the Ford Friction Modifier, GM additive, and the Chrysler additive, and they all do the same thing. There is a rumor that got started somewhere that the Ford stuff will make an LSD more aggressive. Not true. They are all there to prevent the clutch chatter. Add some friction modifier and you should be good to go.

Get used to spinning the engine faster. My old setup with 23.5" tall tires, 3.70s, and the late ZX 5 speed theoretically topped out at 172 mph. Unless you're running 185/50/13s or something ridiculously short you should be in a similar range. Here's a tool that will help you figure out your top speed: http://www.geocities.com/z_design_studio/transmission.html If you just want to cruise at lower rpms on the hwy then get the 3.54 that the others suggest.

Just sounds like clutch chatter to me. It's loud and obnoxious, but nothing to be afraid of really. If you don't hear gears cruching and if the diff worked fine before then I'd be 100% that it is clutch chatter. Did you change the oil and forget the additive? The Nissan LSD needs that additive and if you don't have any in there it will chatter like crazy. Even if it has additive in it, I'd put some more in and then find a parking lot and do some figure 8's for a couple minutes and see if it goes away. At least 1/2 of the clutches have been out of the oil for the last 10 months. doing the figure 8's will spread it around quickly.

True, it's not like it won't drive down the road without a rear bar. If you're going to push the car at all it is worth taking note that the US did get the wimpy springs, and to couple that with presumably a smaller front bar and no rear bar means that it's not going to handle very well compared to the non US version.

If you're running street type spring rates, you probably want the bars front and back. If you Chet Whittle or Bryan Lampe you don't need as much roll control because your springs are 400% stiffer than stock or more and the springs limit the roll. My car with 200/250 in/lb springs needs bars.

Well I didn't park in a garage, and it didn't leak that much. It wasn't too big a deal, just an annoyance more than anything. You're right though, it was pretty ridiculous to put up with it for that long.

Yep, that's what mine looked like too. There was no wet gas around the filler on mine though, so you might want to check for that Zsaint. I kept trying to seal that hose on the driver's side there, no luck. I dropped the tank and replaced all the hoses. I changed the hose clamps, etc. I'm fairly convinced that ddezso and I had the same thing going on, and I'm also fairly convinced its a seam leak.

I tried to fix mine about 8 times now over the last 7 or 8 years. Finally I've convinced myself that it is the seam that is leaking. I'm going to a fuel cell, but I know that the tank liners like the stuff POR 15 sells will seal pinhole and seam leaks. That would be my first suggestion, having tried EVERYTHING else myself... I sympathize with you though. That is frustrating as hell, especially when you've just installed new hoses and clamps.

I suppose you're right, but the Z wasn't exactly a high end automobile at the time. It'd be much the same as having a '90 Miata that you've spent the last 16 years staring at lovingly. Sure, you could. But IMO that Miata and the Z in the ad is not worthy of this kind of worship. They're both cheap fun mass produced Japanese sports cars, not some exclusive one of 100 built supercar.

Whenever I see a car like this with ultra low mileage my first thought is -- there's a LEMON. Why else wouldn't it have been driven?

I think Arne's on the right track. When I got my first Z it had failed emissions. His mechanic had tried to lower the needles and they were really uneven and bent. It was pretty horrible. I told the guy to knock $200 off the cost and I'd fix it so that it would pass smog. He agreed, and I bought some new needles and nozzles. A friend of mine did a simple tear down and clean and installed the needles and nozzles, thing passed after that. Also, IME passing smog on a 240 is a tricky business. It has to run on the ragged edge of lean to pass. Once passed, I would richen the carbs up quite a bit and it would run 100 times better.

Find a mechanic who knows SU's.

Most tracks are run in both directions here, just to change it up a bit I guess.

The AZC is the MSA 6-1 header. Look closely at the pics. Same thing...

I bought my volt meter from Harbor Freight for $6, then bought a Bosch O2 sensor at AutoZone for $30. I bought an O2 bung from an exhaust shop for $5 and had a friend weld it in for me. The single wire O2 grounds to the bung, the positive you have to connect to a wire inside the car. then clamp it to the positive lead on the voltmeter and ground the negative lead. Turn it to the 2V scale and it will show you to three decimal places (not that you need it that exact) the voltage. The refresh rate of the voltmeter is a bit slow, so you need to keep repeating your tests until you feel comfortable with your results. The Autometer gauge is great but the O2 sensor they supply was a problem for one of the two guys I was citing earlier. He couldn't get a steady voltage reading until he switched to a Bosch sensor. Then everything was peachy.

I have the MSA 6-1 header and the tubes were HORRIBLY crimped where they went into the flange. I actually took a little bit of time to port the header because it was so bad. I also had to weld some on the #6 hole because there just wasn't any metal to seal to the gasket there as delivered. Although I despise my header, I will say that I think these problems would have been minimal if it were a round port head. No crimping of the tubes in that case... My suggestion is that if you have a square port head you should spend the extra money and get the Nissan Comp header.

He has a restored Z. Not a turbo pushing 25 psi or a 14:1 compression race engine. Narrowband works fine for carbs on a stockish engine. If you're tuning to the Nth degree, then yeah, a wideband is a lot more accurate. If you have a turbo pushing a lot of boost and the slightest bit of detonation is going to put holes in pistons, then yeah, a wideband is necessary. If you're tuning a set of carbs, a narrowband works surprisingly well. I've had TWO friends get on the dyno with their L engines running Mikunis and the dyno operator was eating crow about how "useless" the narrowband was. Both said the narrowband followed right along with the wideband the whole time the car was on the dyno, and one did a full day. Last thing, if you're just using this to tune and you don't want to permanently install the fancy gauge, get a cheapie volt meter and a Bosch one wire narrowband O2. .8V on a narrowband is about 13:1, which is just what you want. Do get a quality O2 sensor. Bosch is what worked for me, and the two guys who surprised their respective dyno operators.