kj280z Posted May 15, 2011 Share Posted May 15, 2011 (edited) Hey all I know that the CV Axle discussion been done several times - I have read all the posts - That's why I'm posting this... Being that several of you have run into the 300zxt shafts being too long in certain instances (various ride heights and an assortment of other reasons), I'd like to try to approach it from a slightly different angle... Firstly, the 300zxt axles are becoming very hard to find... Secondly the 280zxt axles are also hard to find. (I have all of the adapters and CV axles to do both of these conversions so I have all the reference parts) We obviously have 2 options for adapters for both of those CV Axles combinations via Modern Motorsports, but the availability of the axles and some of the challenges folks have faced make it worth a further discussion. I know the 300zx NA shafts (84-89) are too long - but those are very plentiful. Some have raised concerns about various aspects of them not being as strong as the 300zxt shafts - but would they be good enough? I have a shop near me that does a great job of making custom shaft lengths - If I had the center shafts made to the correct length and if they could be used with the 280zxt adapters from Modern Motorsports, that might just be the answer... I'd love to hear the thoughts on that... I'd like to hear some feedback on the correct lengths that folks have run which would avoid all the binding issues and eliminate the need to flip cages and all the rest of the things required to run the Z31T MM adapters... When I start this project within the next week or so I'll be taking my own measurements as well... Just feels like we need a more viable and plentiful solution for the CV Axle conversion - some of the other porsche conversions seem to be way over priced IMHO Edited May 15, 2011 by kj280z Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 15, 2011 Share Posted May 15, 2011 The problem is you not only need the custom shaft, you need the companion flange adapter as well, and I don't think there is one. I haven't looked at the 300ZX NA shafts in a very long time, but I think they're 6 equally spaced holes, not three pairs like the 280ZX shafts. Maybe one of the R230 adapters works, I don't know. I don't think the 300ZX shafts are going to be a weak point that causes problems for the vast majority of us though. Maybe for the guy who is trying to turn 9 second 1/4 mile times... Quote Link to comment Share on other sites More sharing options...
kamikaZeS30 Posted May 15, 2011 Share Posted May 15, 2011 Wait, what else do you need to do to the Z31 Turbo axles besides flip the outer bearing cages? I have been driving mine around for a couple weeks, now, with the adapters, new stub axles and everything. This might be that weird feeling I get in the rear, if they're binding... I hadn't considered that. Quote Link to comment Share on other sites More sharing options...
kj280z Posted May 15, 2011 Author Share Posted May 15, 2011 (edited) The problem is you not only need the custom shaft, you need the companion flange adapter as well, and I don't think there is one. I haven't looked at the 300ZX NA shafts in a very long time, but I think they're 6 equally spaced holes, not three pairs like the 280ZX shafts. Maybe one of the R230 adapters works, I don't know. I don't think the 300ZX shafts are going to be a weak point that causes problems for the vast majority of us though. Maybe for the guy who is trying to turn 9 second 1/4 mile times... John - Thanks for the reply - While I don't have a set of Z31 NA axles at the moment, the pictures I've seen appear that the bolt pattern is in fact 3 pairs of 2 bolts (6 total) rather than 6 equally spaced holes. - If that is true, I'd love to hear if the bolt pattern is the same as the 280zxt CV Axles - if it is, the companion flange adapter from MM for the 280zxt axles should work with a shortened 300zx NA CV axle... Hoping that's the case Edited May 15, 2011 by kj280z Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 15, 2011 Share Posted May 15, 2011 There really isn't much you can do about it unless you have adjustable control arms. Solutions pretty well boil down to lengthening the control arm or getting a custom shorter CV shaft. If you want to check for bind, take the driver's side spring off, disconnect the sway bar, then move the suspension all the way up and down by hand (not with a jack) and see if you can feel the CV bottoming out. Quote Link to comment Share on other sites More sharing options...
kj280z Posted May 15, 2011 Author Share Posted May 15, 2011 Wait, what else do you need to do to the Z31 Turbo axles besides flip the outer bearing cages? I have been driving mine around for a couple weeks, now, with the adapters, new stub axles and everything. This might be that weird feeling I get in the rear, if they're binding... I hadn't considered that. There's plenty of posts on the topic - some had to grind off some material at the end so the shafts would not hit the end cap etc... if you search you'll find it... Some have ruined their differentials because they bind, others have bought re-manufactured units and the companies who rebuilt them used the wrong length center shafts - all kinds of stuff... Since they're pushing the limits on being too long, there isn't too much margin for error so it could be several things. Quote Link to comment Share on other sites More sharing options...
kj280z Posted May 15, 2011 Author Share Posted May 15, 2011 (edited) There really isn't much you can do about it unless you have adjustable control arms. Solutions pretty well boil down to lengthening the control arm or getting a custom shorter CV shaft. If you want to check for bind, take the driver's side spring off, disconnect the sway bar, then move the suspension all the way up and down by hand (not with a jack) and see if you can feel the CV bottoming out. Agreed - I was thinking that if I was able to have this shop make several sets of shortened center sections for the 300zx NA axles, that folks might want to run them with the 280zxt MM adapters I have the adjustable rear control arms, so I'd probably be fine with the Z31T conversion, but it was a real PIA finding the Z31T axles, so I was looking for a more readily available solution... All I would do is work to get the measurements correct, then give out the number to his shop and you guys could get them directly or have them done by whoever you like since it should be an easy part to have made - that is of coarse if you're able to get the adapters from MM I've been trying to call/email Ross for a few days now and have not heard anything... Would love to discuss this option with him... Edited May 15, 2011 by kj280z Quote Link to comment Share on other sites More sharing options...
kj280z Posted May 30, 2011 Author Share Posted May 30, 2011 I installed the Z31T CV shafts with the MM adapters last night. (75 280z) I shortened BOTH shafts by flipping the cages. I had plenty of room on the drivers side, but on the passenger side EVEN WITH the MM adjustable lower control arms, there was no way the passenger side would work (the MM control arms widen the rear which provides more room depending on the camber adjustment). I can now see why so many have ran into issues trying to make this work... The only answer on the passenger side is to run the CV without the end cap (the adapter provides an adequate seal just fill it with grease), and to grind 1/8" off the end of the shaft. Additionally I ground some material off the stub axle shaft (about 1 thread worth)... Hopefully it will be good enough. Test drives so far seem to be that it's fine. No issues with the sway bar hitting the CV boot with the MM rear control arms which was good... I still think it would be worth having some shortened center shafts made for the Z31 NA CVs and to use the 280zxt MM adapters - maybe someday - Now that I have this working I'll leave that to someone else to try... Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 30, 2011 Share Posted May 30, 2011 That's news to me, I thought because of the offset of the diff it was only the driver's side that had issues. How much did you lengthen the control arms, and how did you test for bind? Quote Link to comment Share on other sites More sharing options...
kj280z Posted May 30, 2011 Author Share Posted May 30, 2011 That's news to me, I thought because of the offset of the diff it was only the driver's side that had issues. How much did you lengthen the control arms, and how did you test for bind? It was news to me too, but would explain a lot of the issues people have run in to.... I didn't have to test for bind - it wouldn't even compress enough to install! Once I modified everything, it fit... I checked for bind by removing the spring and compressing the suspension by hand - it is still VERY close though... And yes I'm positive the shafts are installed on the correct sides... I even flipped the cage on the passenger side to shorten it! (flipped both cages) Quote Link to comment Share on other sites More sharing options...
JSM Posted May 30, 2011 Share Posted May 30, 2011 (edited) Nevermind... my post was incorrect. Edited May 30, 2011 by JSM Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 31, 2011 Share Posted May 31, 2011 What is the length of the control arms from center of inner to center of outer pivot? Quote Link to comment Share on other sites More sharing options...
kj280z Posted May 31, 2011 Author Share Posted May 31, 2011 What is the length of the control arms from center of inner to center of outer pivot? I will have the car on a lift to do the bad dog rails in a week or so and I will follow-up then Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 17, 2011 Share Posted June 17, 2011 Any news on this? Curious to see if both sides need fixing as a general rule... Quote Link to comment Share on other sites More sharing options...
kj280z Posted June 17, 2011 Author Share Posted June 17, 2011 Any news on this? Curious to see if both sides need fixing as a general rule... Both sides have to be flipped (shortened) to obtain proper margins and even then they're tight. On the passenger side we did not re-install the cap since the adapter has a machine fitting... we ground off 1/8" of the end of the shaft, then filled the adapter (and CV) with lube and installed without the cap on the passenger side... it has been fine for 400 miles of driving... Bugs the heck out of me that Ross has not called me back or answered my emails on this!!!!! Been over 45 days! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 18, 2011 Share Posted June 18, 2011 Did you measure the control arm length? Quote Link to comment Share on other sites More sharing options...
rossman Posted June 18, 2011 Share Posted June 18, 2011 (edited) I believe wheelman has found a solution. Look at post #40 of this thread. He found that early Pathfinder V6 axles are exactly the same as Z31T axles except shorter. In fact, they are so short that he had to ADD a spacer on one side. Edited June 18, 2011 by rossman Quote Link to comment Share on other sites More sharing options...
kj280z Posted June 20, 2011 Author Share Posted June 20, 2011 (edited) Did you measure the control arm length? John I didn't... I have the MM adjustable LCA's. Which points would you like me to measure for you? Edited June 20, 2011 by kj280z Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 20, 2011 Share Posted June 20, 2011 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. Quote Link to comment Share on other sites More sharing options...
rossman Posted June 21, 2011 Share Posted June 21, 2011 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. If my half shafts end up binding (haven't tested yet), I'd buy a set assuming the cost is reasonable. Quote Link to comment Share on other sites More sharing options...
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