Datsun B210 (120Y) axle

[Fingolfin]

Hi all,
You may be aware I'm working on a 1275cc upgrade for my Mog. (Getting close to completion on that engine.) In preparation for the engine changeover, I procured a 3.9 differential, but after ~$700 spent on the pumpkin, it whines terribly, and new crownwheels and pinions are almost as expensive over again!

So, I have a Datsun/Nissan B210 (or 120Y, or Sunny, depending on where you're from), and it has nearly the same wheelbase as a Minor, and its differential is also 3.9 ratio, and the whole drivetrain on that era of Nissans was derived from the BMC A-Series - so my thought is, could I simply swap the two cars' axles? There'd be complications in brakes, driveshaft flanges, and probably in leafspring mounting.

Does anyone have experience of this? I know Datsun drivetrains are popular in Australian Minors...

[philthehill]

Searching the web the Datsun Sunny B310 is the preferred axle to use as it nominally has the same dimensions as the Morris Minor
You will have to fit new axle perches and make up a new propshaft assy.

On the web search for ................Ozminors and/or Morrisdownunder ...........you will have to register to enter their web sites though.

Phil
PS:- Have a good New Year

[Fingolfin]

Thanks for that, Phil. Happy new year to you too!

I've done some more investigating into this axle, and here's what I've found.

• The differential-to-propshaft flange bolt pattern is very close to a Minor's.
  Datsun: 45mm x 54mm between bolt hole centers with a 57mm circle in the middle (according to design specs - haven't measured the physical item yet).
  Minor: 44.93mm x 53.31mm with a 56.6mm circle (according to the 4:55 diff I've just removed).
  The diff also appears to be close to the Minor's diff dimensions (not much longer or shorter). To my amazement, it looks almost like it could "just bolt up" to the Minor's propshaft. The only way to be sure is a physical test.
• The diff is a Nissan H150, which is usable up to about 125bhp and known for being pretty strong. It has a 3.889:1 ratio. The axle hasn't been deprived of oil that I know of, and the one time I drove the Datsun there was no noise, so I'm hopeful it's in good shape.
• I'd prefer to use the Datsun brake assemblies if possible (8" drums, a nice match, I think, for my MGB disc brakes up front). These use metric pipe connector threads, so I'd need to make some new brake pipes with metric connectors on one end and BSF on the other. No big deal.
• The Datsun axle uses what I want to call a "cantilever" system for handbrake cables, with a single cable from the lever in the cab down to the axle, which acts on a lever mechanism to actuate cables out to the drums. Obviously that doesn't integrate with the Minor's system, but I like the Datsun's system better, and may simply transplant the whole thing over (handbrake lever included - its action is a lot smoother than Mog's). That's nothing I can't handle, except a front cable of different length may need to be made.
• The Datsun axle-to-spring perches are somewhat similar to the Minor's (the main difference being extended mounts for the Datsun's telescopic dampers). If they end up not being modifiable, the usual suspects have Minor-type axle perches for cheap, and welding them on would pose no problems.
• And now the problem I feel uncomfortable about. The Datsun's wheel stud PCD is 4.5", as opposed to the Minor's 4". It should be comparatively simple to redrill the drums to have the Minor's 4" PCD, but what to do about the Datsun halfshaft? (The Datsun does not use a separable hub - instead the wheel bearing and seal ride on the halfshaft itself.) It's easy enough to drill holes, but how does one make splines? Is this something a good machine shop can do? Or is it as simple as drilling the holes, then using a sacrificial wheel stud to "tap" good-enough splines into them?
  The alternatives are to use two different wheel PCDs (and two different wheel/tire sizes - the Datsun rims are 12"!), or come up with 4.5" PCD hubs to fit on the Minor's front studs (and still have the issue of too-small rims...).

Just sharing my findings - though I appreciate any and all input, of course. I'm really captivated by this potential project and I can't wait to dig in!