240Z to Z31T CV Adapter Plate OPTIONS!!!!!!!!!!!

[DatDude]

Ok, so I can see the finish line from a very long journey, that is my 1973 RB 240Z.

 

I have a CLSD from an 1989 Z31T with the CV shafts. I'm trying to get the CV axles bolted into my car but I have been finding out that these adapter options for the CV adapter conversion are PRICEY!!! Especially, when you factor in the price for having to get the 27 spline axles from a 280Z (getting harder to find) and the Modern-Motorsport option. Plus, I don't know why NOBODY developed and adapter for the stock 240Z 25 spline stub axles to just bolt to the Z31T CV axles!!!! People keep saying that it was for strength but I don't buy that. They are not much thicker, and you've only gained just 2 splines. For a stock RB, I'm sure the 25 spline will hold up just fine. I'm just trying to get my CV's under the car. Looking for the welded plate to stock flange option so that I can get my car back on the road. I've seen pictures on Google from what Modern-Motorsports "used" to do, but I need better specs for the plate(steal). I found specs for a plate for the 280ZXT CV's, but I cant figure out why no one has done this for the Z31T CV axles. Maybe I'm looking in the wrong place... Anyone have any answers???

 

Thanks for any and all help you give.

 

 

[NewZed]

There's not a whole lot to the specs. besides a few measurements.  It takes some work to get them right but the whole set of numbers is not complicated.  A center, some holes, a parallel plate.  You could take the 280ZXT CV drawing and change the six holes to four.  cygnusx1 has done 90% of the work for you.  Take the 4 hole measurements yourself.  Make it thinner if you're welding and doing the other side too.  The companion flange dimensions are the same for the 27 and 25 spline hub axles. 

 

http://forums.hybridz.org/files/file/3-cv-adapter-print/

[RebekahsZ]

Put a dollar value on your time. For my time and money, the Chequered Flag Racing prices are more than fair. The fit, finish, and quality are great. If building one of these cats was easy, they would be as common as a Cobra replica.

[seattlejester]

25 splines are quite a bit thinner then the 27 splines. You can put a 27 spline flange on a 25 spline hub and spin it around completely without any interference. The 27 spline hubs aren't the strongest things in the world, but those extra couple mm help. If someone is going to go through the effort of getting an R200 and CV axles, then getting the 27 spline would be a natural consideration. In the stock configurations it seems like the half shaft goes, once you move to CV then it is your stub axles that seem to go, and if your stub goes your wheel falls off the car. Not sure how you are sure the factory 40+ year old hubs will hold up fine with more then double the hp being thrown at it, but if you are comfortable then you are comfortable.

 

You have the bolt pattern from the CV's take that to a machine shop and have them make a plate. Once you have the plate you just need to find a fabricator who can make it for you preferably with a lathe. I will say you have to be careful with the width, the Z31 CV's already seem to bind with the cages flipped, so too wide and you won't even be able to install your CV's. 

[NewZed]

These guys would probably make you one if they don't already.  Four 300ZXT-spaced holes, instead of six 108mm CV holes.  Still spendy.

 

http://www.driveshaftshop.com/import-axles/nissan/nissan-datsun-510-240z-4-bolt-axle-flange-to-108mm-cv-conversion-plate-rear-axle

[NewZed]

Here's another thought, since you're welding - buy some junkyard 300ZXT companion flanges and cut the flange off.  Fit them to your Z car companion flanges.  Weld.

[DatDude]

To NewZed... Good ideas all. But my initial thought while making this post was to find out if someone had already done the leg work with a diagram with this same idea in mind. Then I could just go get the pieces made up and weld them and save myself the manufacturing mark up. I'm soooooo very late to getting a Z and doing a build on it. (But not too late since Sung Kang just finished his build, to tons of interest I might add) I have read many build articles and have done 90% of the work by myself and also have purchased many parts for the build. But It wasn't until about 3 months ago that I realized that I had skipped over/missed something very small, but very big! "25 splines vs 27 spines"! The whole time thinking that I would just buy the MM adapters and bolt my already existing stubs up to it. I've gone back and noticed that most of the builds that I was reading skipped over that part. Especially, if they were 280Z's to start with. These builds are about the "details". Anyway, I just wanted to see if someone had done a diagram to save me the time of having to go out (in the cold) and "exact-it" all up myself. Saving time and money. But since no one has replied with an answer close to that prospect, I guess I'll bite the bullet and spend $700 on the 280Z 27 spline stubs and Modern-Motorsport/Chequered Flag Racing adapter kit. Whichever one can ship it out fastest.

 

But thanks again for your insight.

[DatDude]

To RebekahsZ.... That's exactly where my mind is. Time vs money! I don't think the $440 is a bad price, but then adding in the cost of the 280Z stubs and then the time of what I have to do to get them onto my car.... I just wanted to explore other options. And yes, I do understand that this is a process and that all builds have challenges/extra cost. And I certainly didn't expect it to be "easy". I just want to get my car back on the road!!! LOL... I took a perfectly good running 240Z (except in the winter) and then decided to do a motor swap on it. Then shortly after, I made a decision that I didn't want to live check-to-check any longer and right in the middle of this project decided to go to school full-time. Kinda putting me into the bad situation of not being able to go backwards to what I had but also not having everything that I needed to go forward. Especially, with having to downsize my paycheck to go to school. And this was my daily driver at the time. Anyway, again, this post was more so to gauge where I am and where I need to be in order to get past this hurdle and on to the next. But as I stated to NewZed, I'll probably just purchase to 280Z stubs and the adapters from Chequered Flag or Modern-Motorsport. Just didn't want to give up more money if I could do the work myself.

 

But thanks for your reply. )

[DatDude]

To Seattlejester.... Yes, I know that they are thicker. I've seen them once with my own eyes, but very briefly. So I'm not saying that they aren't an upgrade, because surely they are. Not the best, but enough. I was going to upgrade my stubs eventually to something more "race spec" considering my future power/track aspirations. But this idea was more of a Band-Aid until I saved for the "Big-Boy" parts. Didn't want to spend and then spend again. Trying to cut down the wasted money. Anyway, figured if there was and already R&D'ed diagram out here, I could explore it for cheap since I'd put it together myself. And I'd go into that modification knowing that I'd just baby it and not give it the "full potatoes" (as Chris Harris would say) until the new parts had arrived after saving for them. My mind said, since Modern-Motorsport was selling services for the 27 spline axle where they welded it up by hand, then It must have worked. (at least for a while) So building my own will work as well, just for a much shorter amount of time. So I had no plans of just welding this thing together and flogging it like I stole it. Just a small bridge to get me where I need to go. And yes, I fully understand that these are 40+ year old axles, and that they are basically systems built on systems and that the weakest link will go first. And I want my wheels to stay on my car. LOL... I also understand that these 40+ year old stubs will not stand up to doubling the horsepower, torque and traction (CLSD) that this car was originally supposed to have! That wasn't what I was saying. I just didn't explain that this was a Band-Aid. And a cheap one at that. But it would allow me to put everything back on the ground, get my driveshaft measurements together and get my baby back on the road. Babied at 3000 RPM before boost really kicks in and only traveling about 4 miles a day on roads doing 45mph and under, until the winter time was over seemed in my mind to be a doable prospect. But again, as I stated to the others in this post, I'm really weighing my options. Price vs Time. But after a few more brains have gotten into my post, I think I'm leaning towards just saving and purchase some axles from a 280Z and then go for the Modern-Motorsports/Chequered Flag adapter kit. But we'll see.

 

But thanks for your input. )

[RebekahsZ]

I'm cheering for you-you'll get 'er done.

[NewZed]

To NewZed... Good ideas all. But my initial thought while making this post was to find out if someone had already done the leg work with a diagram with this same idea in mind. Then I could just go get the pieces made up and weld them and save myself the manufacturing mark up.

 

 Anyway, I just wanted to see if someone had done a diagram to save me the time of having to go out (in the cold) and "exact-it" all up myself. Saving time and money. But since no one has replied with an answer close to that prospect,

cygnusx1 did a ton of legwork and shared it.  If cygnusx1's diagram isn't close enough, then nobody's will be (did you even look at it?).  And you don't need to stay outside, bring the 300ZX shaft in to your nice warm home.  The dimensions you need are on the CV shaft.  Or take the shaft and the drawing to whoever is doing this work so cheaply for you.  

 

Your best band-aid for getting back on the road might be to use the u-joint half-shafts, with R200 open-diff axle shafts.  Clip-in, bolt-in, and cheap. 

[seattlejester]

The drawing is crazy detailed (if we are thinking of the same one), you legitimately have to erase the holes made for the 3x2 pattern and change it to a 4x1 pattern matching the CV shaft you have.  You also have the 4x1 pattern on the CV axle that you have, so can't see how much easier it could get, no R&D or time required. Hell if you were lazy enough you could just take the axle and the flange to a machinist/fabricator and say "make this fit this, you have ____ much room...."

 

I have a set of the older MM adapters and they are not simply welded up. The adapter piece is machined with a rectangle to fit the stock z flange very snugly inside and then the flange is welded to the adapter, that assures perfect fitment each time.

 

Concurred, if it is a bandaid and you plan on putting around just throw the stock half shafts in with the input shafts from an R200, bolt on fitment with the CLSD you mention. Last time I was looking for a set a forum member offered a set to me for 40 or 50$ for the inputs, half shafts can be acquired at low prices if you don't have yours and they are the same from the 240-280z. Unless you are drastically lowered you don't need the CV's especially while driving around at 3000rpm staying off boost.

[DatDude]

Thanks RebekahsZ. ) Pushing hard for the finish line.

[DatDude]

To NewZed.... You're right. Sygnusx1 did do a lot of the work. And with your help of shining light on that link, has given me a good head start to what I was thinking about making when I made this post originally. My statement was just basically saying that I was looking for someone with the "exact same idea" as myself. To modify/rig up an adapter to fit the 25 spline stub axles to a 300ZXT, CLSD, R200 with CV axles. Plenty people have done this conversion (in different ways I might add) to the CV's for the 280ZXT. But I just couldn't believe that of all the builds on this site, no one had tried that same thing with the 300ZXT drivetrain parts. I couldn't have been the first person with this idea. So I wanted to see if anyone had decided to make my specific adapter. BUT.... Maybe they did, and decided that it wasn't cost effective. I was just going to snatch up the idea, if plausible, and see what a machine shop would think of making the parts for me. (cost) But yes, I did look at the blueprint that was in the link. And since then, I have revisited that idea of building the adapters myself. I really don't want to spend $700+ on parts that I could use said money elsewhere. I have even gone and blueprinted my own adapter off of his with the four holes so that I could take it to a machine shop on Wednesday. So trust, you've been a big help and all options are still on the table. Just need to talk to the folks that would make the parts. The using the junk yard 300ZXT flanges was a good idea as well, but where I'm from, you rarely see these kind of cars. Just grandma's Buick, a Ford Contour or a Chevy Caprise. I'm working with limited options here, you know. So the net is my best friend for this car. But I'm still searching for parts. And we'll see what I can come up with in the mean time while I'm waiting on the machine shop for the quote. As for the U-Joint half shafts with axle shafts, been looking for those too. All in one package just to buy. Been seeing u-joint axles but not the shafts that slide into the R200. If you have a lead on those, cheap, then I would greatly appreciate that too. Thanks Again.

[DatDude]

Good Info again. And yes, since reading this post again, I have been searching for that very BandAid. Half Shafts and input shafts for the R200. Unfortunately, I went all in with the CV shafts working and just bolting right up, but again I missed a few details in between my reading. So needless to say, I sold those half shafts a long time ago. LOL.... Didn't think I would need them. Lets see if I cant buy them back for cheaper. SMH... Thank you guys again for helping me with my problem.