There has been a lot of disscussion about the series 1, 2 and 3 240Z. The 280Z has similar changes and at first glance August 77 seems to be the change over point.

I often see threads getting side tracked about these differences and when they occured.  A lot of good inforamtion, but its scattered over a lot of different threads and difficult to find again.

This might be a goed way to collect information about these differences and share with other members.

 

To start:

Rear Panel

Im making brackets for my 240Z bumper mod. The first thing I noticed was the bolt pattern for the bumper brackets. According to the parts fiche they changed around 5/77.

Before 5/77 the 2 bolts were in a diagonal pattern, left low and right high. The patterns were the same on the left and right side. After 5/77 the right side bracket changed to two in a vertical line.

Why they changed this is a mystery to me. It may be something to do with the 260Z outside the US. They were not used to mount the 280Z bumper.

The second difference is the four slots (two long and two small) changed to one long on the left side.

I have some photo's of the differences. The green car is a 76 and my red 280Z is a 5/77 (VIN: 403100). Mine is probably one of the first with this later version.

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Good idea Chas.

My 6/77  vin 404578 car has the same bolt pattern & single slot on the rear.

 I've been curious about the slots for a long time. What was their purpose?

Excellent idea Chas! Mine is definitely like the top photo, 1976

I wonder what the thin indent (offset) was for? It has screw mounting points too... My plan is to fill it in during the bodywork.

Edited January 28, 20169 yr by wheee!

How to restore book by Wick Humble has some info on change over dates recalls and tech bulletins. There's a lot to read though!

Good for cabin fever climates. 

9/75 production build 1976 280Z

I not sure why they made the slots? Could be to help remove any exhaust fumes from under the rear area? The indent seems to be there since the series 1 240Z, but it changed shape a little over the models.

I cant work out why they would change the bolt pattern. It wasn't used on the 280Z and I don't think it was used on the 260Z outside the US.

My theory on the slots is  wind noise reduction.

I replaced a side mirror on my 90 f150 looks same as ford but it whistles at 30/35 MPH.

My 01/77' had this before it was replaced so I thinking the change occurred at the beginning of 77' production. 

1977 and up got the better ignition modules, apparently.  Plug gap spec. increased.  Unless the R plugs are used.  Weird spec.

 

In 77, they changed a lot of stuff.

Doors.
Floor stampings.
Seat mounts.
Door locks.
Rear wheel cylinders (and brake shoes?)
Shoulder harness belts relocated to the strut towers (or was that 76)
Different quarter window trim because they don't need the hole for the seatbelt.
Different rear panels where the speakers go and speakers on both sides.
Relocation of the seatbelt warning lamp or something like that came up in a recent thread?

Edited January 29, 20169 yr by Captain Obvious

I believe the fuel tanks are different too. That is why the 76 tank is preferred when going EFI or L28ET in an older car, it is a direct swap...