DATSUN DIFFERENTIALS

Datsun used several different sized differentials in their independent-rear-suspensioned sports cars. The 510 sedans used the R160, the early Z’s used the R180, and the later Z’s used the R200. There are also several other variations out there (R190, R230, LSDs, Ks, clip-ins, bolt-ins, etc). The diff name refers to the size of the ring gear in millimeters, ie the R160 has a 160mm ring gear. Here’s a link to more info than you could ever need - Hybrid Z diff info.

The R160 and R180 are known to be direct bolt-in swaps in the 510 and the early Z, but there are a few important differences. The larger ring gear in the R180 allows it to handle higher torque motors before destroying itself, but the R160 can still stand up to some pretty surprisingly powerful motors. Also the R160 weighs about 8 lbs less and the case is 1/2″ narrower, thus leading to this story. The R160 and early R180 use the same inner bolt-in stub axles (properly known as the side flange). But since the R160 has a narrower case, it needs to use a longer dust cap. (Left – R160, Right – R180).

The dust cap size difference keeps you from being able to swap them between diffs, so don’t get them mixed up in your parts bin! Doh…  The dust caps are not that critical of a part, you could just cut them off and use the stubs in either diff if you had too. When I had my CV joint adapters made, I had a R160 in my 510, but now that I have a R180 in it, they didn’t fit. So I cut off the caps, and welded on a pair of caps that I cut off some R180 stubs. Problem solved. If I use them now in my R160, they will just have a 1/4″ gap between the dust cap and the axle seal.