NewZed

Page 10 here looks interesting, although the whole catalog is worth browsing - http://www.ntn.ca/Catalogues/NTN/CVJ-ForIndusrial_en.pdf Here's one of the Pathfinder axle threads, only because it was mentioned, sounds like you're going a different way - http://forums.hybridz.org/topic/72805-using-pathfinder-and-zxt-axles-to-install-30-spline-nismo-lsd-kit-56k/page-3?do=findComment&comment=942447

Thinking about brass, steel and shifting, the other teeth that grind are the splines on the coupling sleeve and the dog teeth, if I understand things. Maybe yours are rounded or damaged. That's the thing about rebuilding transmssions, it seems like you'd have to rebuild them before they start grinding, if you want like-new performance after the rebuild. Once they start grinding the parts that don't come in the rebuild kit are getting damaged.

You wrote "61.1" twice, in the title and in the post. Did you mean 6.1? 61 volts would be five batteries wired in series. I don't think it's possible to generate 61 volts from six 2.1 volt lead-acid cells (the typical 12 volt battery). Sounds fascinating though.

Use your meter on a 9 volt or 1.5 volt battery. It will probably read 0.9 or 0.15.

Regarding the star "walking" on the shaft - it's either supposed to be free to move around, or it's supposed to stay in one place. But walking to a new spot and getting stuck so tight that you have to bang it off with a hammer can't be right. It's either a cause of the problem, or a result of the problem. Might be worth focusing on how and why that happens. If the balls were pressing on the circlip, that force would be pushing against the star and cage, preventing it from getting stuck on the inner spline portion. Since the star is stuck, that suggests that the star walked doen the shaft first, got stuck, then held the balls against the clip until it popped out. I've found that the weird small stuff is sometimes the clue to solving the big problem. Good luck.

Thanks for doing that work and posting those videos. It seems like the star/bearing race/cage walking down the shaft might be the problem, not a result of the problem. For whatever reason the star walks, pulling the balls with it. If the cage and star walk far enough inward, that makes the end of the axle get closer to the stops, effectively. After the star walks down the shaft, is it possible for the balls to be on the circlip and the end of the axle to be on the stop, binding the axle end and balls between the stop and the circlip, until one or both give? If you could lock the star in place at the end of the shaft it might solve the problem. Just a guess. I can't imagine that the star is supposed to move on those splines while in use. You might compare a stock Q45 shaft to the MM shafts and see if the star can walk on the stock shaft, and measure the distance from balls in the star wheel and the axle end, with the star walked inward, and see if it's longer then the cup can take. A fix might be as simple as peening some splines on the inside of the star to stop it from walking. As far as shaft length - I can see that I missed something when looking at the drawings and the shortest shaft may not be at full compression. The hub doesn't tilt when it pivots around the control arm axis, it stays essentially perpendicular to the ground. Two things happening, one pulling it away and one drawing it closer. Looks like pulling away wins based on your videos, the shaft is shortest with the wheels hanging (as jmortensen has said in previous posts). Thansk again, those videos show a lot.

If you mean the half- or drive-shafts by "axles", then rolling it around won't hurt anything, The hub axles and bearings are separate self-contained assemblies. The mustache bar bushings are available in the Nissan stock rubber from or you can get aftermarket polyurethane replacements.

I'm short on terminology also, so my post might not have made much sense. And I don't understand the fine details of the CV joints, that's why this thread is interesting. Rossman and texis offer the best suggestion, especailly after you've had so many problems. Put one or both axles back together with no boots and watch what happens as you lift the suspension up and down and rotate the wheel. You've probably seen this thread (it's in the FAQ's), it mentions joint problems if you put the cages in backward (Post #48) and has pictures of assembling the joint. Circa 2005, yours is not a new problem. http://forums.hybridz.org/topic/25054-r230-axle-assembly-a-pictoral-review/ As far as the length, everything pivots around the inner control arm attachment point. The inner CV joint is above the control arm attachment point, therefore gets longer as the wheel drops and shorter as the wheel rises. You can verify this by moving the suspension up and down as suggested. If your diff really is lower its CV joint axis might be the same as the control arm's so it will be shortest when level. See the attached picture. I could be wrong but that's what the picture tells me. Maybe one axle joint is binding under load and pulling the other side out. Another possibility, hard to verify in the garage.

I think some people call it the "star wheel" or something like that. But in bearing terms I think that it is the cage and race combined. Maybe the stops are there more to keep the axle from moving far enough to let the balls out of their "cage". Axle with "cage" moves (too far), balls get left behind, come out of cage, get stuck between cage and circlip, circlip pops out on the reverse movement. There is probably a critical relationship between the cage, cup, stops, circlips and cage/star position on the shaft. The balls should never be able to come out of their spot between cup and cage/star, but yours might be. Hard to tell what happens first but you might be able to work the joint with the shaft off the car and figure it out. I would guess that the stops should have been taller. As far as the stops getting worn down, if you take a compass to the drawing in the FSM, draw some lines and take some measurements you'll see that the drive shaft is most extended with the wheels hanging, and most compressed with them up. You might not have needed that spacer at all, and your problem was the stops all along. The spacer may have destroyed your stops. Sorry I didn't suggest this sooner, you could have at least considered it and taken some measurements on the car.

You might run that pressure test again, or a leak down test A slanted motor shouldn't cause a 17% drop from high to low. Reporting the values from all cylinders would tell more also, not just two. That link works. Sounds terrible. Good luck.

Link doesn't work and youtube is misspelled. If you get the head off again maybe you could rig up a drill motor to spin the cam on the bench. Should be enough oil already there to keep things lubricated and you can watch each valve moving. Support the head by the ends and the valves can open and close freely. Or stand it on end. A piece of hose from the drill chuck to a bolt head makes a good flexible coupler. Have you done a pressure check to make sure each valve is closing properly? Maybe you've got a bent one that is hanging and getting dinged by the rocker arm.

Maybe your problem is related to why Nissan went to a dual-cone synchronizer. Might be cheaper in the long run to take the bellhousing from your ZX trans and do the 71C conversion. It would be interesting to see what the friction surface looks like on the 2nd gear ring when you take it apart. Another thought regarding the blocking ring is that all "brass" may not be the same. In other words, the coefficient of friction may be different between Nissan rings and aftermarket rings. Maybe just replace the 2nd gear ring with a factory Nissan ring. They're about $50 at courtesyparts.com. Edit - one of these might buy you a few RPM also - http://www.courtesyparts.com/nissan-motorsports-roller-bearing-pilot-bushing-p-341365.html

That's pressure that you're reading, not compression. The gauge used can have a big affect on the number you get. The big tubular adapters that come with some gauges can drop the pressure reading by 60 psi. The adapter tube and gauge volume get added to the combustion chamber volume so the effective compression ratio drops.

If you're going to try some other fluids, the Swepco/ATF blend is definitely worth a shot. Fluids have a big impact. I had an old 78 5 speed that ground the 2-3 shift with Valvoline 75/90. Redline MT90 fixed that problem. Then I tried the MT90 in an old 1980 5 speed but still had a problem, with 1-2 and 2-3, so tried the Swepco/ATF blend. It raised my RPM limit before gridning, by about 1200 RPM (memory, may not match previous posts) over the MT90. This is on old worn, or rusted synchros, so may not apply to new. I used the Swepco based on JMortensen's recommendation's in past threads. He has a lot of history with the blend at 50/50. 50/50 felt a little thin to me so I upped the Swepco to 75%. Not cheap though, about $15/quart. The newer "syncromesh" type fluids are thinner, about 30W, from what I've picked up on the web. You need some higher viscosity to get things spinning, and the materials and synchroniser pieces are designed aorund a certain type of fluid. Re johnc's comment about new fluids in old design transmission's.

Did you rebuild with Nissan baulk/synchro rings or aftermarket? I've seen internet reports about "problems" with the less expensive rings although details were sparse. And did you record the ring/gear clearances, just for comparison? Was the 2nd gear clearance similar tothe others, or on the high or low side? I had a similar high RPM shifting problems with an old junk yard transmission and found that the Swepco 201/ATF blend was significantly better than both MT90 and Valvoline 75/90. I ended up at 75/25 blend. Just one more anecdote.

The first page of this thread will answer a lot of your questions - http://forums.hybridz.org/topic/49194-differential-cv-lsd-hp-torque-r160-r180-r200-r230-diff-mount/ The R200 mustache bars are out there, typically from $50 to $75. Hardly worth messing with trying to drill spring steel (see the thread above, first page). As johnc inferred, your and other's, and my, difficulties come from trying to save money by using existing parts and puzzle-piecing it together. Study the Modern Motorsports parts below, and the link inside with the install pictures and you'll see pretty much everything that needs to be considered. The first page of the link above shows some shortnose R200 install parts also. http://www.modern-motorsports.com/catalog/product_info.php?products_id=74&PHPSESSID=9e25b7fab3e9baf204ae3aa017e3d66f I have also read that the stock control arms may interfere with the big flanges on the short-nose diffs. Most people seem to have aftermarket control arms for this diff swap. One more thing to watch out for. It was noted in the Pathfinder axle threads.

The 280Z body style changed in 1979, with the ZX (in the States). None of the ZX drivetrain mounting hardware will work on the Z car, except the two studs in the cover and the holes for the front mount. The ZX's don't have a mustache bar. The only good differential part you'll get from a 79 ZX is the differential assembly itself, which might be a longnose R200, but could be an R180. It's been proposed that the diff and its carrier from the shortnose Q45 R200 (which you most likely have) will swap in to the long nose R200 case with its ring and pinon gear intact. You might need sleeves for the botls thoguh. This allows you to use typical longnose R200 hardware to bolt the diff in to the car. Then you need half-shafts to get the power to the wheels. The most difficult and/or expensive part of the swap seems to be getting half-shafts of the right length with the right bolt pattern. If you come up with a good inexpensive plan I'm sure it wil be popular. I've been through most of those threads and every now and then they'll get brought back to life. Somebody with the Pathfinder axles blew up a CV joint when the axle shaft pulled the joint apart. His adapter thickness was off a little bit, not thick enough. There's a recent thead on a similar problem with the Modern Motorsports kit. He didn't have an adapter but had custom shafts, the joint pulled apart. Good luck. Take extra care on those half-shafts.

.390" = 9.9 mm. That's what the atlanticz table shows for exhaust valve lift for the J cam. You're actually measuring .4 mm over what's shown for the M cam. Odd. It's also odd that the part numbers both end in E4126 for the L24 and L28E A cams, in the table, and show the same specs, but the FSM numbers are different, 11 mm vs 10.5 mm. Maybe someone assumed that the A's were the same. Just goes back to verifying what you read. Maybe someone could start a "measure your valve lift" thread and get some more verified numbers. Just for fun.

Looks salty. There must be some kind of reason. Four intake runners feeding six ports seems a little weird. I like the custom bracket for the nylon zip tie. Probably a weight saving measure.

73 shows 11 mm also. I've looked before and can't find the ZX (P79, P90) numbers in the FSM's, so can't compare those. Who knows from where the numbers came.

10.4 mm vs. 10.5 mm - atlanticz table vs. 1978 FSM data. I thought the topic was about the validity of the data in the atlanticz table, not driveability. You said the atlanticz table was completely inaccurate and we're trying to determine if that's true or not.

Too bad there are no references on the atlanticz page to tell where the information comes from. The L28 A cam specs in the table are 0.1 off from the 1978 FSM, so probably not copied from there. Somebody must have measured or has another document to work from. 0.1 is pretty close though. One A cam measurement shouldn't be enough to paint the whole table as completely innaccurate though. That would be some radical extrapolation. Picture from the 1978 FSM Engine Mechanical chapter:

This site is pretty handy and suggests that one part is pre-5/77 and the other after. Click on Part #5 and you'll get another window. http://www.carpartsmanual.com/datsunS30/DatsunZIndex/Engine280Z/EFI/AirFlow/tabid/1614/Default.aspx

Thanks for clarifying my misinformation. I had originally written a comment that it seemed odd that MM would sell an axle that was too short, but edited it out. But that does appear to be the case. When a car at stock height hits a bump it will drop or rise to the height where the joints pop apart momentarily so too short is too short no matter where your ride height starts. If the axles are designed to work with the adapters then MM must have bad information on how long the axles should be to work right, since they come as a package. Weird how this stuff happens. Good luck to the OP on getting it working. Seems like there aren't many easy deviations from stock when it comes to the rear drive shafts, everyone has problems.

Be careful if you decide to buy a "new" Q45 axle from a parts store for the CV joint. "New" means a totaly different design, that will only work with the manufacturer's shafts. Only "rebuilt" will have the Nissan design. You said that that the PO said you had MM axles. I don't see that MM sells a CV axle/center bar/shaft. Maybe the PO meant 5 lug axles as shown on the MM page - http://www.modern-motorsports.com/catalog/default.php?cPath=32_53 You probably have the two short shafts from a Q45 and the same problem that SUNNNY Z and RB26 had. Interesting problem, those two drive shafts seem to be a lot more trouble for everybody, than you would think from looking at them. I'm still trying to find the cheap way to get a VLSD in my car. I'm stuck on axles.