The other moustache bar bushings - the wavy rubber washers

[Patcon]

The weights have been found on some cars

[Namerow]

1 hour ago, CanTechZ said:

Here is a picture of the early set up,  thanks @Mikes Z car. Note that the bushing presses into the bottom of the mustache bar. The bottom of the bushing has a flange that is rubber coated and does not have a top flange. There is washer with serrated rubber at the top and a plain steel washer at the bottom.

A lot of this discussion about design changes is starting to sound familiar.  There's another Topic somewhere from about 2 years ago that has an extended discussion with lots of photos.

Re your photo of a car with no lower rubber washers fitted to the MB, it's hard (but not impossible) for me to believe that Nissan would have decided to put the wavy rubber washers on the top rather than the bottom of the MB end mount.  After all, the diff weight should be forcing the MB down, not up.  That said, I don't understand why the MB bar in the photo is jammed up against underside of the car.  Possible answer:  The owner used the diff as a jacking point.  As a result, the whole diff/MB assembly got pushed up against the wavy washer and got stuck there.

Let's assume for the moment that maybe there is only one of these rubber washers fitted at each end of the MB.  If that's the case,  it makes more sense to put them on the bottom of the mount rather than the top.  By the way, that's the way it's depicted in the Parts Manual diagram.

What makes more sense to me, though, is that the wavy washers should be fitted to the top and the bottom of the MB end mounts, so that they're put into a slightly pre-loaded state after everything has been tightened up in assembly.  In the parts listings, I see four different iterations of the 'Stopper - Differential Mounting'.  In every case, the manual specifies 2 uppers and 2 lowers. 

I don't know exactly what to make of the arrangement shown in your photo.  Maybe someone with an unmolested early Z (is there such a thing?) can chime in.

 

[Namerow]

1 minute ago, Patcon said:

The weights have been found on some cars

But PN 55490-E8300 (the weight) doesn't seem to appear in the parts manual.  Those add-on rubber washers don't appear to be listed either.

[CanTechZ]

27 minutes ago, Namerow said:

A lot of this discussion about design changes is starting to sound familiar.  There's another Topic somewhere from about 2 years ago that has an extended discussion with lots of photos.

Re your photo of a car with no lower rubber washers fitted to the MB, it's hard (but not impossible) for me to believe that Nissan would have decided to put the wavy rubber washers on the top rather than the bottom of the MB end mount.  After all, the diff weight should be forcing the MB down, not up.  That said, I don't understand why the MB bar in the photo is jammed up against underside of the car.  Possible answer:  The owner used the diff as a jacking point.  As a result, the whole diff/MB assembly got pushed up against the wavy washer and got stuck there.

Let's assume for the moment that maybe there is only one of these rubber washers fitted at each end of the MB.  If that's the case,  it makes more sense to put them on the bottom of the mount rather than the top.  By the way, that's the way it's depicted in the Parts Manual diagram.

What makes more sense to me, though, is that the wavy washers should be fitted to the top and the bottom of the MB end mounts, so that they're put into a slightly pre-loaded state after everything has been tightened up in assembly.  In the parts listings, I see four different iterations of the 'Stopper - Differential Mounting'.  In every case, the manual specifies 2 uppers and 2 lowers. 

I don't know exactly what to make of the arrangement shown in your photo.  Maybe someone with an unmolested early Z (is there such a thing?) can chime in.

 

Here is a snip from my 1970 FSM that shows the rubber washer on top and rubber on the bottom face of the bushing flange with a steel only washer on the bottom.  I looks to me like originally the washers were only meant to contact when the rubber in the bushing was starting to fail, see the note about the 5mm dimension.  In 2005 I had my mustache bar bushings replaced and new washers installed.  It only had one rubber serrated washer of the early type on top and one steel washer on the bottom. In 2005 I was able to get a new early top washer from Nissan.