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Everything posted by JMortensen
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If you're trying to seal the seams, the factory used seam sealer. You can buy seam sealer from the auto parts store. I left mine bare, and plan to shoot some oil in there every couple years. In areas where they were exposed to water, there was rust in the seams in my car despite the factory sealer.
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It's the angles that matter, not whether it's downhill or uphill. There have been some very clever people who have figured the angles using laser pointers. Search "pinion laser pointer" and I'm sure you'll come up with threads by Pop N Wood and bjhines among others who document what to do and how to do it. John-You're a fountain of knowledge. Note to self: don't trust memory. 29 lbs... that's a lot of weight.
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There is a reason they use yellow. "Race car" or not, it's a much better choice than blue...
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Thank you. If memory serves, the longnose R200 weighs ~100 with a Nissan LSD. I believe the shortnose that the OP is looking at is right around the same.
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I don't want to sidetrack too much, but was that Toby's car and do you know the weight of the diff?
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I'd put that sumbitch in everything!
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I have to double check when I actually get the parts, but the price looks like it is going to be $495, no shipping charge. I called a bunch of places and that was the best I could do. The specs are there, so anyone can take those and go get their own quote if they like. All I ask is that if you come up with something cheaper, let me know so that I can try and get a better deal for everyone else here.
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Just FYI Dan, I just did some measuring on my car and found that the CV axles changed 3/8" from full droop to full bump and were shortest at full droop, and that's with the diff in the stock location. For the OP, I'd consider using a different differential. I've been waiting for someone to do a Ford 8.8 IRS. The diffs are cheap and plentiful, there are lots of options for gear ratios and limited slips and lockers, and they're tough. Some come with aluminum housings, so I believe they would be lighter than an R200 or 230. I've found weight for the aluminum version quoted at 65 lbs but haven't verified it myself.
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You can bolt it in if you have the parts needed from a 280Z R200 (mustache bar, curved link behind the diff, the companion flange, and the side stub flanges). Then you need to worry about the halfshafts being too long. You can cut the axle down to make it work, several people have done that and documented it, search and you'll find info. You'll also find info on the driver's side being too long at www.betamotorsports.com in the bench racing section. If you get the 300ZXT adapters from www.modern-motorsports.com, you'll have a similar problem where both of the CV axles are too long. I'm going to have a new solution for that problem in the next couple weeks. I can either sell you shorter CV shafts so that they don't bottom out when you use Ross's setup, or I could sell you an entirely different CV setup, but my setup would require you to either buy my stub axles or to upgrade to 280Z stubs which have 27 splines.
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I have probably an equal amount of Matco and Snap-On, and they made up about 1/3 of my total tools when I left wrenching as a profession. I haven't seen a real difference between one and the other in terms of performance. I would think that your money will go farther on the Matco truck. I would also suggest that you start with a Craftsman set of basic tools, because really, buying Snap-On or Matco 1/4 or 3/8 extension sets is a waste of money (I speak from experience). Last I heard, Matco had a MUCH better deal on tool boxes than Snap-On. That was probably 10 years ago, but the price difference was ridiculous at the time. I would look at Craftsman for boxes too. Just because you paid more for tools doesn't mean that you'll get paid more for the work you're doing. If the tool helps you do the job faster, then it might be worth it. If it's just a socket or an extension, buying "the best" is probably not going to make any difference in your speed whatsoever, but it will put you deeper in debt.
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I've already ordered a prototype set along with the other completely new axle setup, they should be here in about a week and a half to 2 weeks. When I've verified that everything looks right, then I'll make them all available at the same time. I still have to work on pricing and I need to figure out exactly what the cost is as delivered before I can set the price.
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Thanks Rossman. I don't want to get too far out in the weeds, but the real question is how much benefit it provides, and the axle manufacturer that I worked for years back who made 1541H and 4340 chromoly shafts with rolled and cut splines said the difference was negligible. I've looked online and found no hard numbers, but lots of speculation either way. I don't know if the splines on the axles I'll be selling will be rolled or cut, but I will find out and advertise it so that you guys know. I do know that there will be a lifetime warranty and they'll be chromoly, so the material is already ~40% than the stock alloy. I am sure that the upgrade in material is worth far more in terms of strength than rolling splines on the stock material would be. OK now for some info. I can confirm that CV lengths are shortest at full droop as has been widely reported previously. Available CV travel on the 300ZXT CV's is 1 11/16". Total change in length on CV shafts on my car from full droop to full bump is 3/8". I was measuring from where the retainer snap ring would rest against the CV on the inner to the CV shell on the outer, as the center of the CV is right at the same length as the shell at full extension, and the cage gets in the way so it's much easier to measure the housing. Here are my measurements: Driver's side Bump: 11 3/8" Level: 11 1/4" Droop: 11" Passenger's side Bump: 12" Level: 11 7/8" Droop: 11 5/8" Now this is not yet the length of the shaft that we need, because it is the measurement of the shaft when totally topped out, and it doesn't include the length added by the splines. The splines add 2.5" (1.25" per side). Since the amount of travel used is so little, we should be able to make these numbers work for both the billet flanges and the welded flanges. Add another 13/16 or .8125" of length to put the CV in the middle of its travel. Then subtract .375" because I had the MM companion flanges which give 3/8" more space. So basically take my measurement and add 2.9375" or 2 15/16" for a total length that would be accurate on a Z with stock control arms and Ross's welded CV adapters. We can use the level measurement because it is pretty close to the middle, and we get a length of 14 3/16" for the driver and 14 13/16" for the passenger side. This is roughly 1" shorter than stock on the pass side and 1 3/16" shorter on the driver's side. According to wheelman, the stock driver's side shaft is 15 3/8" long. The real question is whether that driver's side will work on the passenger side. So let's reverse the numbers a bit. Take the minimum pass length of 11 5/8", add 2.125" to it and you get 13.75", add in the total travel of 1.6875" and that is the max allowable length of the shaft before it bottoms, and you get 15.4375". So by my calculations, putting the driver's side CV on the passenger's side clears by .0625" if you have the MM welded flanges. Just based on variations in the chasses, I think this is cutting it a little close. That's not considering bushing deflection, etc. So I would say that if you are running MM's billet companion flanges, you can run the driver's side CV on the passenger's side. If not, you should buy both the driver's and passenger's side CVs. I have forwarded the lengths to the axle shop and I will let you guys know when they are available for ordering. These shafts will fit 300ZXT axles ONLY. If you have Ross's kit with 280ZXT axles, you have a couple of problems. First is that those CVs are pretty hard to get apart from what I understand. I haven't done it myself, but I think you need to cut a crimped band off of the outside if memory serves. Not that big a deal, but when you go to put them back on... ??? If it is possible to disassemble and reassemble those shafts, if there is some trick to it, I'd love to hear about it. I can't do the measuring on my car because I don't know how far the CV adapter sticks out from the stub axle, but if I could get reliable measurements from somebody, the same sort of CV axles could be made to fit. I think the assembly/disassembly is too big a hassle for most people.
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I've finally made some headway here. I've read what wheelman suggested, and he was nice enough to give me lengths via PM and I've looked at my own car as well. Wheelman suggested putting the driver's side shaft on the passenger's side because it is 1/2" shorter. I tried to relate these measurements to my own car, which has the chromoly companion flanges from MM (which give an extra 3/8" clearance AND I have 1/2" longer than stock control arms). Based on what I saw on my car, I have some doubts that running the LH axle on the RH side gives enough clearance. If it does, it's got to be really tight, very close to bottoming. On my car, the passenger side is about 1/8" from bottoming out with the stock passenger side shaft in there at full droop, and that is with 7/8" more room than would be available on a car with regular length control arms and the wider MM tig welded adapters. Today I'm going to take my springs out, put stock length control arms in and check the measurements at full droop and full bump, and see where we need to be to put the CV shaft in the middle of the outer race. I expect that I'll come up with a shaft length that is an inch or so shorter than stock for both sides. We will also finally have proof of where the CV shafts are shortest, whether that is at full droop or full bump or level. We'll see. I'll try and post pictures this afternoon. I've sent my passenger CV shaft to a shop with the most reasonable prices so they will have the spline size and groove locations. They are going to make chromoly CV shafts to whatever length we need, and I will sell them through www.m2differentials.com. That means you guys have a phone number to call if there is a problem, I actually respond to emails, M2 takes credit cards so you don't have to screw with Paypal, etc. We will also have a totally new stub and CV swap that we will be releasing in a couple weeks. It will have some pretty major advantages over what is currently available, I'll keep you all updated as that gets closer to happening.
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Suspension alignment tools for the home garage
JMortensen replied to Zmanco's topic in Brakes, Wheels, Suspension and Chassis
You really do not want to raise the car up, adjust it, then set it down and check, then raise it up and adjust it again, etc. When you set the car down the wheels will be pinched underneath the car, and you might dial in 3 degrees of neg camber but the car will sit on the ground with 1 degree positive. You would have to roll and bounce the car around a lot every time you made an adjustment to make sure you were getting the right numbers. When I used to do toe at the track I made a mark on the drivers side tie rod that represented 1/8" in and another that represented 1/8" out with white out and I'd move between the one setting and the other. That I could do by jacking it up because I knew exactly where it needed to go as measured on a proper alignment rack. If you don't have such a reference mark, then you should be trying to adjust it on the ground, not jacking the car up. If you can't reach under the car for some reason, you might try putting it on scales, or driving it up wood ramps to wood platforms that are a couple inches tall. Like you said, you need a flat piece of ground. If you don't have that, you could make the platforms level. If you really wanted to get dialed in you could get some slip plates so that the suspension moved freely. 2 pieces of masonite with a big gob of grease in between makes a good slip plate. -
I got a custom net and it came out pretty damn good. I posted pics of it, if you look and can't find them PM me and I'll email you some pics.
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Suspension alignment tools for the home garage
JMortensen replied to Zmanco's topic in Brakes, Wheels, Suspension and Chassis
Why am I not finding Tom's string setup on his site? -
No, these are off of my car, so they are 300ZXTs.
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Rolled or cut splines is a kinda silly thing to argue over. YES, rolled splines will be tougher. But I can't think of a single occasion where I've personally seen splines stripped off of an otherwise healthy shaft. On your typical 4x4 or drag racer axle they always shear right where the spline meets the shaft, usually after some twist in the shaft itself. As I say on the M2 website, if you're worried about whether the splines are rolled or cut, you should just buy a larger axle shaft with a higher spline count. I went and pulled one of my CV's and took a picture, and you can see why cutting (or rolling) the splines further isn't an option. The splined part of the shaft is 1.150", the section immediately after it is 1.068". So at least on a 300ZXT CV shaft, it's not going to work.
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Cutting the splines higher on a 300ZX shaft might not be possible. I know the ZXT shaft has a shape to it, that I'm pretty sure would make that impossible. Also, by the time you've cut the splines, you're already doing most of the work to make a new axle. I can't imagine this saving a lot of money, and if you have the ability to cut splines, you probably have the tools to make your own axles... Just a quick update on the custom shaft thing, I'm getting a bit of runaround. Still trying to make something work.
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John put together that thread showing a bunch of different cages, should be a FAQ. As a general rule, if a tube can be put in a cage without bending it, then don't bend it. A straight bar is stiffer than a bent one. The one exception is door bars, where they should be bent out into the door to give clearance.
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If you can't handle finding and installing a brake fitting adapter or cutting and flaring a brake line to put the right fitting on, you shouldn't be attempting to modify the brakes. Repair and modification are two different things. Someone here used to have the sig line "Everything takes longer than it does." That's true, and I would add "Most bolt-ons don't" or "Parts that fit may require fitting".
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Higher efficiency cylinder head by grooving?
JMortensen replied to mutantZ's topic in Miscellaneous Tech
Pics? -
The 300ZX NA has the tripod axles, and the CV shafts are longer. I don't know if the tripod joints are exactly the same as the ones on the 280ZXT or if they're different. Just not sure on that one.
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The center of the inner pivot to the center of the outer pivot. I'm thinking about trying to have some custom CV shafts made and making that my first M2 Differentials product for Z cars. It looks like wheelman did figure out a solution, but it still required a 1/2" thick adapter on one side. I think it would be nice to just be able to buy the CV shaft (without the joints, just the shaft with splines) and then be able to pop the joints off and put them on the new shaft and you're done.