1970-83 DATSUN Z
  • Over the years you've probably spent sleepless nights pondering the next big Z mod. You've replaced the suspension, the wheels, the interior, maybe even the engine. You've pored over the car devising new upgrades and tweaks and are satisfied with what you've done. But is there anything else to try? Yes...the axle shafts.

    Recently I set out on the ambitious repair of replacing the rear wheel bearings on my 1970 240Z. Previously I had installed an R200 with a 4.11:1 gearset and R200 halfshafts...essentially the standard R200 conversion. But when I had all the parts out I realized the spider joints on my axle shafts didn't exactly rotate smoothly...they were very stiff when flexed in one direction. I had replaced the spider joints a couple of times over the years, but I suspected using a bench press and all the hammering with a sledge had bent the flange ears slightly...binding the joint. Or maybe it was age, these things take a lot of abuse.

    So I started to look for new replacements. The original halfshafts were long out of production of course, and I actually stumbled across a company on Rockauto that sold rebuilt R200 versions. But as you would expect when I tried to order them were out of stock. At one time A1 Cardone sold rebuilt 280ZX turbo CV axles too, but same thing...they were out of stock. And considering I would have to source 30 year old stub axles for turbo CVs it didn't seem like an easy upgrade. Then I stumbled across Wolf Creek Racing and their bolt-in CV joint kit for ZCARs.

    They advertised these benefits:
    - better and greater angulation than U-joints
    - Eliminates vibration from U-joint halfshafts
    - Transmits 2-3% more power to the wheels
    - Reduce rotating mass and unsprung weight

    So the following are some photos of my conversion. This is for the R200, the R180 is going to be slightly different of course.

    BELOW: this is a good view of the halfshaft minus the brake drum backing plate. The conversion is straightforward but I suggest buying new nuts and bolts to replace the original ones. Using old fasteners in a new conversion is "false economy". These bits are easily purchased at the Nissan dealer, I'll post the part numbers when I can dig them up.


    BELOW: The original stub axle and wheel flanges are reused. This is one of my R200 stub axles. I removed the old bolts and pressed in new factory versions.


    BELOW: This is one of the aluminum adapters fabricated by Wolf Creek. One adapter bolts to the stub axle and the other to the flange end on your wheel. The new CV axle shaft fits between them and is held in place by 6 long bolts on each end.


    BELOW: these are the new factory nuts and bolts attaching the adapter to the stub axle. You have to use the correct nuts here as they are thin wall and low-profile. You also will have to find a thin-wall socket to fit into the recess. I torqued mine to 45 ft.lbs with loctite.


    BELOW: The new shaft uses high-performance German 100mm CV joints on the end of splined chrome-moly shafts. Your job is to add grease to the joints at both ends and bolt it in place between the two adaptors. Cleanliness is foremost as you want to keep dirt and grit out of the joint.


    BELOW: This is a shot of the stub axle end. The CV joint is fully greased and the flange has been torqued to the adaptor with the supplied allen bolts. The bolts are high quality and were pre-drilled for safety wire. This is a good opportunity to buy a pair of safety wire pliers and learn how to use them. You should safety wire the differential end before installing the shaft into the car...the wheel end is safety-wired afterwards.

    One complaint I have is that the threads on the bolts were metric but the allen socket was SAE. I damaged a couple of bolts using a metric allen socket until I realized this. I've noticed a tendency for fastener companies to make bolts with metric threads and SAE heads...which is very wrong.

    To install I snapped the stub axle into the differential and slipped the other end in place at the wheel flange to install the bolts. Safety wiring was a bit fumble fingered due to limited space but I got it done. Sorry, I was so anxious to try it out I never took any photos of the final install, I suggest you go to the Wolf Creek Racing website to see what it looks like when fully in place.


    CONCLUSION: The original Nissan/Datsun halfshaft is heavy. When I pull one in/out of my R200 I have to use both hands, and reaching in to push it back in place is tiring. I'm guessing it's 15-18 lbs. That adds a lot of rotating weight to the drivetrain. The friction from four pressed-in needle bearings on the end of each axle shaft also adds drag, especially as the suspension flexes up and down.

    The Wolf Creek CV is so light I can insert the whole assembly into the differential with one hand. I'm estimating it at 5-6lbs. The use of large ball bearings in the joint removes drag as the whole assembly is designed to flex smoothly. It's a very different design than a spider joint.

    On the road the back end of the car is much less "busy". Road noise is reduced and the rear-end feels smoother. The car is easier to push in my garage if I slip my foot onto the ground which tells me the old halfshaft friction was significant. On the road the car has snappier response and in tight corners I can break a wheel loose in 3rd gear...that never happened before. Removing all that rotating weight and friction is the same effect as using a light flywheel on the engine in my opinion.

    So while these CVS are an investment to install I think it makes a significant difference in performance. If one of the parts ever needs breaks I can easily find replacement parts at EMPI.

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