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That's great. Will you just let the axle float between the CV joints? That was my intention too initally. Now I consider that a problem because no manufacturer does that. Every CV axle assembly has a fixed CV end. How much did your modified outside flanges cost you to get made?

If I were you I'd forget the ATF and run over to my local Chyrsler or Chevy dealer. Once there, pick up as many quarts as needed of the Castrol synthetic used in the NV4500 5-speed gearboxes found in the one-ton trucks. This stuff is awesome although quite expensive (around $20 a quart). You won't need to worry about opening up your tranny because what little gear lube remains will blend with the Castrol product. Shifting will be butter smooth (assuming the box is in good condition) all year around.

I did get around to disassembling the inner joint. The assembly is held in place on the shaft by a c-clip like those found on the later CV axle assemblies. I pounded the inner CV assembly off with a lead mallet. The c-clip broke in two pieces in the process. Reassembly would be reversed with new c-clip. I haven't looked into acquiring another c-clip but it shouldn't be too much trouble to locate. In the interim, I'm now looking at using early 80's Porsche CV's for their compactness and strength (smaller units rated to 400hp according to Ross at MM). Custom axles would be needed but that isn't a major hurdle. I have drawn up plans for 3/4" thick adapters on the inner joint and 1" on the outer. The outers would bolt directly to the stock 240Z-280Z stub axle flange. The whole outer assembly should be about 2.5" thick, less boot, which I'm thinking will allow the boots to clear the anti-sway bar ends nicely without modifications to the bar links. Plus, Porsche type CV's are readily available and cheap.

Also look at the seal contact area of the driveshaft slip-joint. If there is a groove at this location a new seal may not help. You'd have two basic choices at that point. Try to find a two-lip seal (I'm assuming the original is only single lip variety) that will place a seal lip in an unworn area or speedi-sleeve the slip-joint in the seal contact area. I've used these on many applications with great results. A speedi-sleeve is a very thin stainless steel ring of varying diameters and widths used to repair the seal surface area on balancers, yokes, etc. when excess wear prevents proper oil seal operation. Do a search on the web.

Sweet... I hope to soon have some basic drawings for the adapters for all to see. I don't have any fancy software so I have to do it the old fashioned way with pencil, ruller and compass. I'll be heading out to a few machine shops with hopes of finding someone willing to make these without emptying my bank account.

Sounds great. I just got my Porsche axles. These CV joints are super strong. I now plan to have a 1/2" thick adapter machined to nestle between the R180 CV side flange and the Porsche CV joint. On the outer side, I am still considering using Ross' billet pieces and Z31 CV joints. Alternately, I could use the Porsche CV joints and another adapter plate between it and the 280Z stub axle flange. It would be much cheaper!! The upside would be identical CV's that are readily available if needed.

Very interesting, I haven't got the axles in hand but they are suppose to be appeoximately 3 3/4" across with a bolt pattern on a 3 1/2" diameter. These should still be easily stout enough for my L6 as I don't push the car very hard anyhow. They also have at least 5 (maybe 6) balls in the much heavier joint housing. I've already conceded to custom axles. I'll know more when they are in my hands. Photos and more info will be coming...

The Petronix is merely a triggering device. The MSD creats an extended high voltage discharge across the plug via the coil. The coil produces the high voltage. I'd check to see if there was a full 12 volts to the coil and then maybe consider swapping out the coil. Another issue can be carbon tracking in the cap due to the higher sustained voltages, bad rotor or even a damaged carbon button in the cap. I'd look at the simpler possibilites before writing off the MSD box or coil.

I've given that setup some serious thought. Initially, I was going to do that very thing. I have four of the outer CV joints for that purpose. The outer CV and associated spring (I assume you're refering to the internal spring that preloads the axle shaft on a 280ZXT axle assembly) can remain if you use Ross' 280ZXT companion flanges. The problem arises that with the spring installed the inner CV joint (original 720 4x4) innards are pushed into the back of the cup and will lump over with every rotation. This joint was not intended ot be used in such a manner. Maybe a nylon button could be inserted in this joint to prevent bottoming out. Otherwise, life expectancy cannot be long in this arrangement. If the spring is removed then the axle can float between the inner and outer CV joints. The same effect takes place within the CV joints as mentioned above but without the preloads. Some have said to have run this arrangement for many years without detrimental effects. My newly thought out conversion has a fixed CV joint at the diff and allows the axle to float within the outer CV joint to account for suspension movement. This is the way all factory CV axle assemblies have been produced (at least, all that I've ever seen). It would be a fluke if I found out the Porsche CV were dimensionally the same as the Nissan pieces but a pleasant surprise none the less. I still suspect I'll be having custom axles machined for this project.

I just purchased a complete set of Porsche 911 axle assemblies, including the diff flanges and stub axles. The idea is the have the Porsche diff flanges machined to mimic the R180 CV side flanges (assuming there is enough material to do so) or machine a simple 1/2" thick spacer to bolt to the R180 side flange and then bolt the Porsche inner CV to the spacer. It's only a matter of having axle shafts machined to match the Porsche splines at one end and the Z31 splines at the other.

I'm looking at Porsche inner CV joints as a possibility. Custom axles will probably be the only, although expensive, course. I just added a rough drawing of my Z31 CV joint modification to my gallery. This will give viewers an idea of what I'm trying to do. In the drawing I show bolts and nuts retaining the CV to the R180 side flange. I don't think there is room for the bolts head though. In that case, I'd simply install studs and weld them on the backside to prevent movement. Alternately, I'm now thinking of the possibility of having Porsche stub axles machined to minic the R180 side flanges. This would allow a direct bolt-up of the Porsche CV. It would also move the CV further inboard providing for more axle articulation. Again, custom axles would be required.

Yes, the early NISMO R180 uses the bolt retained side flanges. I could swap out to R200 but don't want or need to. I'll have to look into fixed CV joints from other makes as a possible alternative. In the mean time I'll continue pursuing the present path I've chosen. Thanks for the feedback.

I don't think so. If you had to pop the end cover off and push the shaft outwards through the housing to reveal the CV innards then this is the outer CV joint. The CV joint I'm refering to has the short axle machined into it that goes into the diff housing and engages the diff spider gears. The reason for matching the CV joint to the shaft is to ensure wear pattern matched parts go back together properly. I also think there is a disassembly/assembly criteria here but I can't valid it. Maybe someone else can?

Here goes... I have the basic components to complete the CV conversion of the NISMO R180 LSD differential in the 240Z. The parts list is as follows.... 280Z stub axles, Ross' billet z31 (4-bolt) companion flanges, 300ZX turbo axles with custom length shafts, R180 differential CV side flanges (6-bolt pattern) from a late 720 4x4. Here's the kicker... I'm thinking that I will cut the short shaft off of the inner fixed CV joint housing and remove the seal dust guard. A companion flange can be machined which friction fits over the lip on the inner joint (where the seal dust guard would have been pressed on) and then welded both sides. On the housing side, the weld would need to be stitched to allow room for the bolt heads. This flange would be stepped (imagine a short top hat) so mounting suface is moved out from the joint housing allowing for the 6 bolts to be inserted for attachment to the differential side flange. Once welded up and cooled down, the CV joint can be reassembled and driven onto the axle shaft. The only pain is if the joint ever wore out the process would need to be repeated entirely with new stepped flanges and inner CV joint housings. I don't see this as a monumental detriment since these joints rarely fail. The original thought was to allow the axle shaft to float between to CV tulips. I don't see this as a viable path since every manufacturer has gone to great length to design their CV shafts with a fixed end. Input?

When all else fails grab a manual. I pulled out the book for my Xterra since in uses CV axles up front. One end is fixed and the other allows movement for suspension travel. To disassemble the fixed end you would clamp the shaft in a vise and whack on the outer housing to drive it off the shaft. Apparently, it has a split ring to retain the shaft in the joint. This would be similiar to the retaining ring which holds the axle assembly into a R200 diff. I'll shoot pictures as I disassemble one and post them for all to see.

Jeez, that sounds so easy...just kidding. If I'm reading right I need to dislodge the inner CV joint by whacking it with a soft-faced mallet? Is the inner snap ring round? Does the entire internal assembly come out of the housing this way or does removing the axle allow for more rotation of the cage allowing removal of the bearings? Has anyone pictures of this? I've tried rotating the joint and there appears to be no way to dislodge the balls. I'm trying to come up with a CV conversion for my NISMO R180 LSD. I already have the proper differential 6-bolt CV side flanges. I have the 6-bolt inner tulips to match the side flanges also. I have the 4-bolt outer CV tulips which will bolt ot Ross' billet companion flanges. If I use this combination (6-bolt and 4-bolt) the axle shaft can move (float) within the two CV's. I don't thibk this is good practice. The Z31 has the fixed joint up at the diff. I'm thinking that I can disassemble this joint, machine a 6-bolt flange to weld to this inner joint housing and have the equivalent of the Z31 axle assembly to fit in my 240Z. I hope that makes sense. I'm a visual guy, pictures...PLEASE!

I got my axles ($52.50) this morning. These are the 4 bolt type. It took about 45 minutes to pull them with hand tools. Luckily, the car was off the ground on welded rims for easier access. The axles are in good shape aside from a little dirt and rust. The last steps are purchasing the billet Z31 companion flanges from Ross, having the custom axles machined, assembly of the axles and tearing the rearend apart for struts, springs, mustache bar, bushings, etc. That should take about 15 minutes...LMAO!

Is this R200 just sitting out of the car? If so, then you'll have to fab a piece of long flat stock to bolt to the pinion flange with access for the socket to reach the pinion nut. This stock will keep the pinion from rotating with the impact gun. Another set of hands would help too. If the R200 is still in the car this flat stock still works wonders but a good impact should have the same results. You might also try using a long breaker bar wedged against the ground or chassis and roll the car slightly forward in neutral to break the initial torque. The nut would then come off with relative ease.

While doing some quik searching I came across this bit of info... "There are only two differential companion flanges. The 84-86 models have a slightly offset bolt pattern (i.e. make a rectangle). The 87-89 models have a equal bolt pattern (i.e. make a square)." Does this imply that the earlier 4 bolt pattern (at the axle stub flange) is rectangular and the later is square? I ask because I want to use Ross' billet companion flanges which appear to be square. I don't want to waste time or money on parts I can't use.

I have a chance to pick up some axles kinda cheap ($50 a pair) from a 84 300ZX turbo but I have to pull them. Before I make the trek to the source I'd like to know if these are the axles I want. I'm looking for the Z31(?) CV axles in the 4 bolt pattern. Are these it or are they the earlier 6 bolt pattern? Thanks for any help!

How you got a decent deal of the column. A bearing supplier would have been your best bet for finding a suitable replacement. Also, most auto parts stores have bearing/seal interchange books on hand. You could measure the dimensions of the bearings and look through this book to find a match. One note here, most auto parts stores are manned by unknowledgable persons (sorry auto parts guys/gals if I hurt your feelings if you actually do have a clue) willing to work for minimum wage. That's been my experience since Advance and Auto Zone have prevailed in the market place. I long for the good old days of real parts counter people. I worked part time for Advance years back just for the discount and left after getting a 10 cent raise for 6 months service. They called to rehire me because the customers were upset not getting the parts and info they needed to fix their cars. Sorry to get on a rant.

You would need an inline pulse generator. It mounts between the tranny gear and the cable. This unit produces the square wave pattern needed to drive the Autometer speedo. The speedo has a small switch (mounted externally) you would use to calibrate the gauge. It is covered in the instructions provided with the gauge. I have never had much luck with these inline generators. I ended up modifying my tranny to accept a reluctor ring and VSS (vehicle speed sensor) to feed my Autometer speedo and the PCM for the Chevy 4.3 Vortec V6. While this is not installed in my 240Z, the principles and application remains the same. This was accomplished by machining a reluctor gear to be a friction fit (also drilled and tapped for 3 setscrews to hold it in place) over the speedo gears on the output shaft of the tranny. I then was able to drill and tap for a VSS to line up with this reluctor gear. The clearance has to be very close for accurate pulse generation and fixed so it can't rotate in or out. Another choice would be to machine a bung to fit where the mechanical gear goes in so that the VSS is perpendicular and centered to the reluctor gear. One more note, I used a 4x4 VSS because it has threads allowing for adjustment. The car version slips into a fixed hole and is held there with a small bracket.

I did not follow the rules of experimentation when using Acetone. I was on a 700 mile road trip (mostly highway). I felt this would yield better results due to a reduced variation in load and engine speed. The test bed includes purchasing the petrol from one source to provide more consistant results. The problem I have with that is the petrol will vary each time the station tanks are replenished null and voiding that constant. While there would be some measurable differences if the acetone is actually benefiting combustion and increasing mileage there should be a marked improvement in mileage across the board regardless of where the petrol is purchased. I failed to get that results but believe me when I say that I really wanted to.