Unsightly Shutline Syndrome

Today, we’re pleased to introduce DTW reader, Bruno Vijverman, who poses a question which has been bothering him of late. 

Image: Author’s collection

Bill Mitchell considered the 1965 GM cars to be his best work. And he may very well have been correct: The already beautiful Buick Riviera’s styling was cleaned up with the hidden headlights it was always supposed to have, the Chevrolet Corvair was restyled in a faintly Italianate fashion, while the regular Chevrolets had a more dynamic and flowing look if compared to the somewhat boxy 1964 models.

The same could be said of the other full-size offerings from Oldsmobile, Buick and especially Pontiac. The GM flagship Cadillac was of course also fully restyled for 1965, and is generally regarded as a handsome, and in view of the era and fashion, relatively uncluttered and cleanly styled car.

I also like the 1965 Cadillac. Apart from one thing: the weird trajectory of the shutline between the front and the rear door on the four-door models. Since this caught my eye I cannot “un-see” it.

Photo 02: Note door shutlines. (c) Chron.com

My hobby is collecting American car brochures. Living in Europe, 1960s US cars are not seen that often on my streets for a personal visual inspection, and because my brochures only offer a two dimensional view of the cars, initially at least, I had never noticed it.

Although the unsightly shutline first manifested itself in 1965, I will use the 1966 Cadillac as an example because this was only a mildly facelifted version of the 1965 car and the brochure for the 1966 model demonstrates my point in the clearest manner. If you look at the white car on the cover (lead photo, top), there seems to be nothing wrong. The shutline between front and rear door runs broadly along the same slightly curved trajectory as the one between the front wing and front door.

But when you look at a photograph of the actual car (photo 02, above), it immediately becomes apparent that GM marketing was not happy with the way the actual shutline turned out and decided to resort to some creative retouching to hide it. One imagines that they hoped that the prospective client would be sufficiently distracted by seeing the entire car in person in the showroom that he wouldn’t notice the awful truth….

Author’s own collection

By the way, things get even weirder with the illustrations on the inside pages of the brochure (above). Here the shutline is suddenly perfectly aligned and almost arrow-straight! GM’s ad men were creative with magazine advertisements as well: Cadillac’s cleverly hid the shutline from view by either showing the four-door car in black, or even in rear 3/4 view with the front door open! (See below)

It is difficult to imagine that Bill Mitchell was happy with the way this shutline turned out either- so I assume there must have been some engineering reason that necessitated it.

Perhaps it has something to do with the very slightly concave shape of the bodysides? One can theorise that when opening the rear door, a more or less straight-down shutline would cause the front edge of the rear door to make unwanted contact with the rear edge of the front door. However, this does not explain why the shutline between front wing and front door drops almost perfectly straight down.

Author’s collection

Also, contemporary full-size four door US cars from AMC, Chrysler and Ford don’t seem to require this unusual arrangement. The cars from Buick and Oldsmobile were similarly affected, but the full-size cars from Pontiac and Chevrolet were not. The reason for this is most likely that Cadillac, Buick and Oldsmobile employed the GM “C-body,” while Pontiac and Chevrolet used the smaller “B-body”.

The unsightly shutline was eliminated with the second facelift of the C-body for the 1969 model year, visual evidence that for GM styling, correcting the original shutline was deemed necessary.

I have discussed this anomaly with fellow enthusiasts but unfortunately nobody has been able to provide a convincing explanation. We can’t ask Bill Mitchell anymore (and I fear this also goes for his colleagues in GM’s styling studio at the time), so I turn to Driven to Write and its knowledgeable readers. Who can shed light upon this anomaly?

Perhaps fretting about shutline trajectories borders on OCD but rest assured I neither wear an anorak nor have ever owned one. But given that DTW has its own minor obsession with car ashtrays, I trust the readership can sympathise with mine.


Author: brrrruno

Car brochure collector, Thai food lover, not a morning person before my first cup of coffee

24 thoughts on “Unsightly Shutline Syndrome”

  1. When the rear door opens it is is simply swivelling around its hinges. The convex outside has to go somewhere and the rear edge of the front door is styled to provide the necessary room.
    The front door hinges operate differently and position the opened door body outside the front wing

    This is not possible on rear doors because it would prevent the front door from opening when the rear is opened first.

  2. Interesting question. I think it has to be an engineering requirement so that the rear door does not foul the front when opening, and also allow the front door to be opened when the rear door is open.

    If you look at this 1965 Cadillac, the rear door could not be hinged like the front door, or the front door could not be opened when the rear door is open.

    1. The doors are kissing each other, in public. Nobody would dare try this stunt again. I think it is safe to assume a fair amount of hand-finishing went into every Strich Acht.

  3. On the later cars they changed the hinge design both front and rear. The front door front edge now turns inside the front fender. They had to move the hinge axis onto the door, and closer to the front edge of the door.

    On the rear door, in order to get the hinge axis close enough to the rear door front edge, they had to create a rather tricky b pillar that extends out.

  4. Designing a front door hinge is no trivial task and that’s before you think Avantime.
    TVR found an elegant solution but had to create a very individual door design to fit

    1. In TVR:s case it wasn’t so much a question of hinging the door as of fitting it. Fitting doors and panels on a GRP-bodied car is close to impossible without giant panel gaps because the panels can’t be made with tolerances that small. By designing the car so that the front hinge is somewhat shrouded by the bonnet they could concentrate on having aircraft industry panel gaps only at the rear of the door, saving the fitters endless of time and certainly their minds.

    2. Good point about GRP doors. When Saturn was producing cars with injection moulded doors they had to have large panel gaps because injection moulded is accurate but not dimensionally stable (expands with temperature).

      Buyers didn’t like the gaps and Saturn had to drop the plastic doors. Too bad because they had a lot of advantages.

      Maybe Saturn could have done something like TVR. Fix one edge of the door skin and “float” the other. And disguise the expansion and contraction with design like the TVR door/fender.

  5. Welcome, Bruno. An interesting piece, both on shut lines, and the sleight of hand used in advertising. Even the most venerated designs aren’t immune from some shut line trouble:

    1. You can bet on the French to go one better when it comes to madcap design details.
      Something like the most complicated door hinge mechanism can be found on the Renault Avantime

    2. Unreal ! I would have remembered a door like that, but those were never sold in North America.

    3. The Avantime’s doors are 1.40 metre long and weigh 55 to 60 kgs. In normal Euro parking spaces it would be impossible to open them far enough to get in or out of the car.
      The solution was this mad hinge design that moves the door about twenty centimetres forward and creates room for entry

      Consolation can be found in the fact that it’s a French solution and they never managed to produce these hinges in the necessary quality.

    4. I think the Soarer / SC400 was for the same purpose, the door was quite long and it allowed the door to be opened with less width.

      What was the purpose of such large doors on the Avantime, since it was a coupe and it looks like one would still have to move the front seat forward to get into the rear ?

    5. I don’t exactly know why these doors are so long. Maybe it’s for more comfortable access to the rear seats, compared with ‘ordinary’ two-door cars, where it’s always rather an exercise for contortionists. An Avantime owner I knew told me that his kids even got in the car without moving the front seats.
      The door length might also have esthetic considerations. With the FWD proportions and the rather massive rear part of the car, a short door stuck to the front wheel may have left an unsightly length of rear window and wing to the eye.

  6. A far more interesting topic than the ashtray stories that come up here, for me a as non smoker anyway. I think Dave hit the nail on the head here, but also agree with Angel Martin. Would be interesting to look further into this topic.

    1. I used to chew tobacco rather than smoke in the car, so I was more interested in cupholders !

  7. I see an optical illusion, the apparent trajectory of the shut line depends on viewing angle.

    The front door hinge change for 1969 is interesting because there must have been a sound reason to use two very different designs on the same car in 1965, but it fell out of fashion rather quickly and has never come back.

  8. The mechanics are fully covered by Dave. And now a different take on Detroit cars of the mid sixties, since nobody here seems to know about the variations on the basic cars that GM made. Or has mentioned it, anyway.

    Their situation was complicated by the need to make both a four-door sedan and a four-door hardtop body. Dave’s first comment picture shows a four-door hardtop, while the second comment photo shows a four-door “formal” sedan, yet another variation compared to plebeian BOPs (BuickOldsmobilePontiac) except for one giant Oldsmobile “limo” built like the second Cadillac Dave shows. So there were three types of four-door machines from GM.

    Four-door hardtops had only a vestigial stump emerging from the floor on which to hang the rear door and anchor the front one, so that the side glass could be frameless – there was no full B-pillar on those cars. Where the rear doors could be hinged and provide adequate strength considering the tumblehome was a poser, which meant asymetrically vertically to the body so the door would open sideways and not up as well at the same time, which problem seemed to dog some European cars. I can tell you from experience that the resulting body rigidity on Detroit four-door hardtops was pretty hopeless and the rear doors were much lighter than the fronts. Quivers and rattles abounded when the doors were slammed shut. Rattles on the move were also standard as the front and rear windows rubbed against each other. Applied to all the Big Three’s cars in four-door hardtop form. Safety measures eventually marked the demise of that body style. Obviously doors cost more to engineer than sheet metal, so the same ones had to fit all the C-body cars no matter the body style.

    For a more uncluttered look, the two-door hardtop was the favoured style for people without children over these four-door models. As a Google search will show, the preserved cars of today are mainly two-door hardtop versions; two-door sedans were bought by the relatively impoverished as the cheapest available, and looked it. Ladling on the envy with dowdiness was Mitchell’s way to make people spring for a more upmarket and expensive car. Few people these days want to preserve some mouldy old four-door, hardtop or sedan or especially a two-door poverty spec six cylinder sedan with three-on-the-tree manual transmission.

    The same ruse of curved shutline as being discussed for the ’66 Cadillac was standard equipment on the full size Chevrolets (and other GM cars) from the early ’70s. Take a gander at a 1974 Chevrolet. That all changed when the rather exceptional for an American car, in my view, 1977 smaller full-size Chevrolets were introduced, along with a bit of engineering discipline as GM market share began its decline. The corporation had to buck up. By 1984, the Fisher Body Division of GM which had designed all the bodies for the various manufacturing divisions up till then was wound up, and its reponsibilities transferred to those divisions to operate separately. Fits improved dramatically from then on. In the 1960s, GM divisions designed the cars, and Fisher Body told them how close they could in fact make the the bodies to the designers’ styling whims. Hardly an ideal situation, and no doubt a contributing factor to the execrable fit and finish. The most amazingly intricate rubber door seals abounded to somehow get all the parts to at least rest somewhere near each other and not have wind whistle at speed.

    If you look at the 1966 cheaper cars than Cadillac from GM, like especially Oldsmobile, the ’65 and on Olds were a total mess to look at in profile due to the styling kickup incorporated at the rear of the rear door. It never seemed to be pressed or fitted properly. I remember that awkwardness but not the front-rear door curved shutline, which they also had when I searched for a look. It seems like a small point to obsess on to me, but we all have hobbies and hobbyhorses of our own! For example, the original ’66 Olds Toronado slayed the Buick Riviera for road presence in the flesh in my view, made it look quite ordinary by comparison. The Buick had a puffed-up look like a marshmallow to its sides with wheels sunk inside the body towards the centre.

    The four-door C-body regular sedans with an actual B-pillar were cheaper to buy than the four-door hardtops, looked much dowdier, and the subject door shutline didn’t even line up with the middle of the B-pillar. Nobody cared. The prevalent public consensus was that imports were “puddle jumpers”, and your average American and Canadian was so conservative they overlooked cack-handed fit and concentrated on size and “style”. Made ’em feel rich to have a big car. I lived through the times and the attitudes. A lot of we younger car enthusiasts at the time used to look at these Detroit blunderbusses with scorn, chucked together with zero pride as they were. Couldn’t budge the majority though; big car = automatic superiority over small one, no matter what a piece of dross it was, and small cars were “foreign” to boot. It took the Japanese invasion a decade until the late ’70s before people finally began to notice that things like hoods, trunk lids, doors and trims, both interior and exterior, could be made to fit and it cost no more to do so.

    The best of these ’60s GM designs on the road and perhaps not in pictures were the ’65 Chevrolet and the Canadian Pontiac which was built on the Chevrolet underpinnings and a smaller car than US Pontiacs. When newly introduced in late 1964, they looked genuinely awesome for the time, introducing the “coke-bottle” look. The ’66s and later were mucked about with, with slight updates, grilles and different gingerbread each year, and immediately lost the purity of the ’65s. The giant GM cars were nowhere near as handsome as the Chevrolets at any time during that late ’60s era, in my biased view. Depending on your predilections for a rigid car body over style, my favourite four-door ’60s Detroiter was the ’63 and ’64 Chrysler full size – which was smaller than the GMs and Fords but of unit body construction. A solid machine. Still huge, but the ’65 replacement was a gigantic wobbler on wheels to compensate. Bloody awful things to pilot around those were – one should have needed a bus driver’s licence to operate it, a big bag o’wind. What a letdown in engineering to suit the market – they sold much better, of course! Those were the sign of the times. The “My garden shed is bigger than yours” sort of thinking.

  9. Thank you all for your comments- we have definitely moved much closer towards the “solution”.
    I must make a correction to my original text where I claim that contemporary cars did not suffer unsightly shutline syndrome.
    Some do, as I discovered while carefully re-examining photos on the web. However, in most cases it is not nearly as prominent as with the 1965-1968 Cadillac. The 1974 Chevrolet mentioned by Bill Malcolm for instance certainly has a “curvy” shutline, but in this car that curvature is duplicated in the shutline between front door and front wing, making it more palatable to my eyes at least.
    The lack of space between front and rear doors when compared to the space available between front door end front wing definitely seems to be a major factor. A very tricky (and no doubt expensive) hinge would probably be the only option, which not many beancounters would allow.
    And finally, thanks for opening my eyes danieljocallaghan. And here I was thinking the XJ was a flawless design. Ouch.

  10. Could I be the only person in the world who quite likes this shutline? To me, it offers strong forward momentum, particularly since the car sits slightly lower at the front than the back.

    1. I guess the reason why I don’t like it is because it is a design compromise to use cheaper components. That might be acceptable on an economy car, but seems stingy on the supposed “Standard of the World”.

      Note that the earlier Cadillacs didn’t do that. They made the extra effort on the B pillar.

  11. 1959 – 1960 GM NOS Right Hand Rear Door Lower Hinge GM # 4783026

    1965 – 1967 NOS Left Hand Rear Door Lower Hinge GM # 7664861

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: