I used to work for a company that made paint materials.  One reason clear coats became really popular in the 90's was that they could hide a lot of base coat defects.  Water-based coatings had orange peel and without the clear coat it was very evident.  If you look closely at most new cars' paint you can see the orange peel under the clear coat.  Look at your reflection in a door panel and  it will be wavy and distorted.  But the surface looks shiny and smooth.

The clear coats solved the problem with metal flakes - but created another problem - over a short period of time in hotter sun regions especially - the clear coats started to crack - at first it looked like fine scratches in the paint, then got worse over time as the clear coats increased “grazing” until they started to flake off.

 

The problem as explained by the BMW Factory Tech's -  was UV light passed though the clear coats and heated up the color coat under them. The difference in the coefficient of expansion of the two coatings caused the clear coats to crack as the color coat expand more rapidly under them. 

 

In 1972 BMW and VW had such problems that new cars sitting in stock were crazing before even being sold. I worked for a BMW/DATSUN dealer then.   Lots of customers with BMW’s had their cars stripped and repainted - under extended factory warranty - cars up to 3 years old were covered. 

 

The solution at the time - was to mix a small amount of color with the first application of clear coat - then put a second clear coat over that. That made the heat transfer between the color coat and the final clear coat more slowly and evenly…

 

Do agree that by the 80’s newer paints solved the problem by more closely matching the coefficient of expansion of the two different materials. 

The UV problem happened again in the late 80's.  All of those old Ford and Chevy trucks you see with gray primer showing after large pieces of paint peeled off were because of a change in the E-coat chemistry.  It was actually UV light passing through the coating and degrading the bond between the coats.

Everything you wrote sounds familiar, just about ten years too early.  It would be good to see some history showing what, exactly, Datsun was doing on the 240Z's at the factory.  A second clear coat on top of wet base coat would be different than a clear coat on an already baked base coat.  I think that 73 has a more modern clear coat applied than any 240Z ever had.  It's not a "period correct" paint process.  Today's clear coats would be thicker than the wet on wet clear.

I still think that 73 looks too shiny.  Too "wet".  

Silver 78 is up today.  Already at $21,000.  Sold for $29,000.  Not bad for a big bumper car.

https://bringatrailer.com/listing/1978-datsun-280z-85/

 

Edited February 26, 20214 yr by Zed Head

Bought this for a friend. 67 chevelle 383 stroker. 15k. It's currently in the port of new york

More silver.  Another 78.  One just sold for $29,000, above.  Might be too late, the market is saturated.  This one has had a recent oil change though.  And it has the mini towel bar, for the one next to the sink.  And a rear luggage rack.

https://bringatrailer.com/listing/1978-datsun-280z-86/

Edited February 27, 20214 yr by Zed Head

I'm currently struggling with panel alignment on my 280Z.  It looks to me like the front edge of the hood is too high on this silver car (like mine is).  I've tried to raise the fronts of my fenders, but I'm fairly certain that the fenders weren't that high originally.  I must also admit that I had to patch my fender tops for about 18" back from the front edge, so that might also be messed up.

The first lines I typically notice on a Z are those around the doors.  Everything else needs to be adjusted to fit after those lines are set, I think.  You can't adjust the two door jambs.

The guy in the 78 BAT listing right above your post might be hiding those lines.  None of his pictures are directly from the side.  Here is the other 78 from post #556.  The gaps are even all the way around the door.

Actually, there is one, just one, that is close.  But shots from both sides, straight on, can answer a lot of questions about a car's body work.

He thankfully shows the Gorilla tape interior.

 

48 minutes ago, siteunseen said:

He thankfully shows the Gorilla tape interior.

 

Mine was much worse.  His isn't bad, one small piece.  It has the typical gouge marks from the seatbelt latch.  Looks like somebody was loading rebar.

2 hours ago, Roberts280Z said:

I'm currently struggling with panel alignment on my 280Z.  It looks to me like the front edge of the hood is too high on this silver car (like mine is).  I've tried to raise the fronts of my fenders, but I'm fairly certain that the fenders weren't that high originally.  I must also admit that I had to patch my fender tops for about 18" back from the front edge, so that might also be messed up.

This a problem many of us have had to deal with, the hinges get a bit worn and sloppy over the years, if you loosen the screws holding the hinges to the inner fender, push straight down on both sides of the front of the hood and tighten the screws while still applying that downward pressure. That usually fixes the problem but sometimes the slots on the hinges have to be notched out to lower the hinge a bit more.