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Z31 Axle Swap R200 CLSD - M2 Differentials

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JMortensen    235

No. I was selling the shorter CV shafts through my company M2 Differentials. I also had Z31T companion flanges made for the 27 spline stub axles. I had an issue with one batch of shafts that I produced. None of that has anything to do with Modern Motorsports or Chequered Flag. 

I gave up on Joe's supplier, because like I said, I got promises and no parts for about a year. I had someone else make the parts that had issues. Those problems aren't in any way related to what Joe is selling.

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John1jz    0
Posted (edited)

Sorry Jon, I'm not really sure who these were bought through as my memory isn't that good. The stub axles have chequered flag written on the outside. I'm not trying to blame anyone or say there is anything wrong with the products Joe is now selling. Just trying to understand why it broke so I can feel comfortable when I launch off the line.

 

On the shaft that broke you can clearly see heat treatment to the end. The original shafts that were sent, maybe from M2, have been painted but as far as I can see there is no sign of heat treatment. The shaft that didn't brake also has no sign of heat treatment. Another friend of mine who bought these at exactly the same time (shipped together) is running a lot of power with an RB30 and not had any problems. He never bothered swapping out the replacement shaft he was sent. Did notice that the shaft I broke is about 1" longer than the one I have just put back in. I changed the shaft with the car lowered on its wheels and I have around an 1" of clearance before I bolt the axle to the companion flange. Interestingly the other side has about half this. Any comments on this? I do have adjustable bottom arms and camber plates.

Edited by John1jz

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JMortensen    235

I think the CV has about 1 7/16" worth of plunge, so at 1" you should be fine You can double check me on that pretty easily. From full droop to full compression on my car the length change of the shaft was 3/8".

 

I sent that batch of axles out and Jamie twisted one right away with his 600 hp turbo V8 drag racer. I figured out what the problem was (incorrect tempering) and recalled the ones that had been shipped without the correct heat treatment, had them treated, and reshipped them out with a different shorter axle. They way they were the first time (lengthwise) was really OK, that's why your friend didn't have any issues. I don't have a firm hp or torque number that they will fail at without the correct heat treat. 

The earlier shafts that I sent out were from a different machinist and so were correctly tempered the first time, so wouldn't have the obvious burnt looking part at the ends.

If you just want better ones, the stuff that Joe is selling now is stronger 4340 and has the correct heat treat. 

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John1jz    0

I had a measure up of the gap between companion flange face and the side of the r200 and both sides measure 408mm.

 

Drove the zed to the drag strip yesterday which is just over 100 miles and it all felt smooth and OK with the shaft swap. Did a slow pass run to check all ok. On the second run I stated the burnout in the water and as I rolled out onto the sticky tarmack, the tyres gripped and this time the prop rear UJ.

 

I'm not having much luck at the moment but will continues to upgrade what brakes and push forward with the car.

post-26912-0-07459900-1494758459_thumb.jpeg

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NewZed    56

I think that's better ID'ed as the "yoke" that holds the joint.  The joint itself looks okay.  And it's actually the flange that let go.  Looks like it might have had improperly sized, or loose, bolts, allowing stress risers at the holes.  To my earlier comment about finessing all of the various pieces and areas that a person can, to distribute the loads most effectively.  The parts look crude and hammer-proof, but they are actually precision-machined at the areas that matter.  People tend to just throw them together and torque 'em down and if they break they go bigger.

 

 Is that a custom shaft, the u-joint clips aren't Nissan style.  Another precision piece, Nissan actually has a range of internal clips to precisely center the u-joint caps.  Installing the u-joints by the Nissan method is a highly skilled procedure in itself.

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RebekahsZ    106
Posted (edited)

I've broken an inner Z31 stub, overheated an inner CV (road course) and twisted 2 slip yokes, one of them completely and dropped it into my driveshaft loop. Not much available (nothing) to upgrade the rear yoke of the driveshaft, except by getting the newest, biggest factory replacement cast steel yoke available. There are a variety of input yokes for the R200 of varying size. I just went thru my pile of R200s til I found the largest one, and found a driveshaft shop that helped me find the corresponding (new) driveshaft yoke to fit it. Then, I found metric "grade 8" bolts to fit it and made sure the shoulder of the bolts crossed the junction between the two yokes to be joined. Then, I used a torque wrench to torque them up. For the slip yoke end, I now use a $200 treated billet yoke. Really sucks, cause in the next couple years I will be upgrading to a T56 Magnum and will need a new slip yoke too!

Edited by RebekahsZ

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RebekahsZ    106
Posted (edited)

Jerry of jnjdragracing taught me to limit axle angles during launch. When drag racing, I raise my rear ride height so that the axle squats toward being straight, instead of beyond straight. I run a stiffer rear spring and shock that stock, and I have installed bumpstops to further stiffen the rear rate on launch. Then I run 11-14# of air in bias ply slicks, so the tires absorb most of the weight transfer and the driveline shock. Drag radials are a quick way to break stuff.

 

The photos of the brown car show how much the stock suspension gets goofed up during launch. Amazingly, it still hooks up well even with all this camber! But driveline angles become dangerously stressed.

 

Compare this to my avatar photo-there's still some camber and toe deflection, but not nearly as much.

post-5903-0-30430800-1494854062_thumb.png

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Edited by RebekahsZ

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