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1974 260Z 300ZXT CV Axle Conversion


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Hello all. I am looking for a R200 CV axle swap guru to help me out.

 

I recently decided to go r200 in my rb25 260z and along with that, I purchased silverminemotors CV axle conversion weld on plates for the stub axles and had two CV shafts mailed to me as well (driver and passenger)

 

These axles are the 4 bolt turbo units.

I welded on the flanges and installed the r200 along with all the proper r200 swap suspension components. After install, i tried to mate the cv's to the stub shaft flanges after fully inserting the splined side into the r200. Unfortunately, they are too long and do not slip behind the stub shaft to bolt in. When i say too long, i mean by millimeters. I can unbolt the strut, bolt the axle on, and then force the strut back into place. This then puts so much outward pressure caused by the CV on the hub that you cannot adjust the coilovers. Not to mention, the axles are fully bottomed and this will cause a great shock load to my differential carrier bearings and axles. 

 

The way i see it, i only have one option and that is to get these axles shortened or have custom axles made.

 

To whom it may concern, the r200 is a 86' 300zx 3.7 welded unit. The differential cover, mustache bar, cross member, and front mount are all off of a 280z with an r200 as well.

 

I have spent days researching this topic and it seems as if nobody ever has this problem. Obviously people flip the cages to accommodate for an extra 3.5mm which almost eliminates any binding problems on suspension jounce. Unfortunately these are aftermarket CV axles that have a tripod joint so I do not have the option to flip the cages. Even if i saved that 3.5mm, i would still have binding issues.

 

Any help would be greatly appreciated. At this point, i think I am just going to have these axles shortened and hope they last. I am just trying to pick anybodies brain who has had this issue before i throw money at questionable tripod units.

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I saw a post recently, can't remember where, where the guy cut a new groove in the axle for the retaining clip, then cut the end off of the axle to shorten it.  It was a simple solution to a common problem.

 

You should post a picture of your axles and tell where you got them.  If you can't flip the cages then they're not Nissan so nobody really knows what you're working with.

 

The "too long aftermarket CV axle"  has been described before.

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6 hours ago, NewZed said:

I saw a post recently, can't remember where, where the guy cut a new groove in the axle for the retaining clip, then cut the end off of the axle to shorten it.  It was a simple solution to a common problem.

 

You should post a picture of your axles and tell where you got them.  If you can't flip the cages then they're not Nissan so nobody really knows what you're working with.

 

The "too long aftermarket CV axle"  has been described before.

I was thinking about doing that exact procedure. Although, I am concerned of compromising the strength of the axle shafts in doing so.

 

The axles were drop shipped to me from rock auto when I purchased the adapter plates. They are trakmotive cv axles.

 

Here are some pictures of the axles installed (After forcing fitment). You can see that the plunge joint is completely bottomed out. I also have attached a picture of the rough compressed axle lengths. I did not fully disassemble them to get the exact length of the main shafts.

52362FED-C6F2-4F60-918C-E8B87E7EF4BE.jpeg

D976E5BF-C5B0-42A3-A11E-4B724071C127.jpeg

D49F5629-4777-4059-99CC-E37BFF17C1EB.jpeg

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Who is selling this kit?  They should know about the axle problem.  Could be the axles, could be the adapters, could be both together.  Save someone else future problems and tell where you got it.

 

jmortensen has done a ton of work on the axle length problem, along with other people.  You could search his name and the topic.  You'd probably have to take yours apart to see what's possible, which might make it impossible to return them.  Seems like the "plunge joint" side would have some room for shortening and cutting a new notch, since it's just mm's.

 

Found some videos just for fun.  There's explosions and stuff.  Remember, smoking kills.  Good luck.

 

 

 

 

 

 

 

 

 

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  • 2 weeks later...

There’s a PDF in my FS thread frogon posted. Covers anything and everything on the swap. 
 

First of all, don’t spend any money modifying those axles. They’re actually not that strong and much much smaller shaft than the OE z31t axles. Though it does matter what power you’re running, along with intended use, trans type, and tire traction. 
 

Secondly, did the silvermine kit come with any documentation on how to weld? Did you adjust it all so that it’s centered? When designing ours we found out the square part of the flange is not concentric. If you have a dial gauge, try to measure your runout. 
 

I’m curious how thick the center part of the silvermine adapters are, as they are adding to the problem of being too tight. That’s why I decided to design these. With the rock auto axles mine just BARELY fit on the passenger side. 

Was it only the passenger side you had problems with?

If that’s the case, I have a solution for you. You could buy another driver side axle. It is shorter. But you will have to swap the diff side Cv end from the passenger unit as the splined end is longer on that side and a DS axle can’t be swapped in as is. They’re actually pretty cheap I think ($75?). 

If you’re over 300whp and intend to drag race, then it might not be the best solution as you’ll probably break them anyways. In that case I’d keep eye out for z31T axles. 
 

Also, the axle is tightest when at full droop. You could install droop limiters to limit how close it gets. You should find if you jack up the suspension 1-1.5” you suddenly have more room.

 

Anyways, rambling now, message me if you have questions. 

 

Edited by mtnickel
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