S30 Construction Theories

[geezer]

This is part of an ongoing study of the S30s construction. I have enlisted the use of this chart to illustrate the S30s movement through the Metal Shop. The chart and the names of the lines are provided by Nissan. This was the Metal Shop Layout that was used at the District 1 Shonan Plant, the District 2 Shonan Plant and the Kyoto Plant. It is the first time I have seen an overview/flow chart of Nissan's Metal Shops. Although several technological improvements would have undoubtedly been made since the S30 run, I believe this general layout would closely resemble the system used.

The jury is still out. Did Nissan use a “buck” system for frameup during the S30 run? That method would consist of permanently mounted stationary sets of hydraulic arms with multiple hydraulic clamps that were electrically controlled. They would be used to position, clamp & maintain tolerances while being welded. The shell would then be unclamped and sent to the next station and the next assembly would move into its place. Or, did they use a traveling platform jig system which consisted of identical platform jigs that would move in unison and stop at each station, where parts were added, clamped, then welded?

Anyhow, looking at this illustration you will not see an exacting layout of the Metal Shop, but a drawing representing how it works (flow chart). The actual configuration would not remotely look like this. This is kind of like comparing a wiring diagram with what is actually in your car.

Notice the names of the lines:

Engine Compartment Line

The actual cowl panel would be a part of the floor assembly. It looks like everything ahead of the cowl panel is part of a separate assembly and built on this line. Just like the Nissan Shatai sketch discussed in an earlier thread led me to believe.

Manual Line

Because of the location in the system, I am led to believe this is for the construction of special or low production number models, suggested by the reduced number of platform jigs or work stations. This line could run independently and at a slower speed then the rest of the system. What comes to mind are the different parts required to build differing chassis and floor pans to accommodate special fuel tanks or suspension components, etc.

Floor Main Line

You can see where the Engine Compartment assemblies join up with the first section of the Floor Line and also the floors that were built on the Manual Line meet up here.

Floor Main Line

More pieces are clamped and welded in prep for the Body Sides

Body Side RH

Body Side LH

In the case of the S30 using this progression of events the quarter assemblies would be built on these lines, and maybe the outer rockers were a part of this assembly?

Body Main

The Body Sides meet up with the combined Engine Compartment & Floor assemblies and are incorporated into the build here. The associated parts and roof panel are added here also.

Body Main final welding

Exactly as it says. You can liken it to the North American Re-spot.

Metal Line

All the leading, grinding, metal finish work is done here, as well as hanging doors, hatch and hood. Then it’s off to Paint.

I would like to point out the linear progression method used here. You can see on the plan the individual stops that would be occupied by an assembly in its particular stage of build. In each one of these segments the platform jigs would move in unison with each other to the next station, then stop until each process is completed. Each station has what is called a process performed. Each process would be a description of the parts added and welded on, the application of sealer etc. whatever work was done. There could be a team of a dozen workers or more at a single station all performing a different process. We have a good picture representative of this.

Also, a metal repair area would be incorporated into this plan along with what we called “the cookie jar” where the excess units above and beyond the quota were kept. In case of a breakdown or production shortfall they were sent off to paint. Also a replacement body/shell could be extracted and used to replace one that met with an unfortunate demise along the way. I’m still studying theories on how the chassis numbers were controlled in the event of a shell being pulled from the lineup.

I believe this is very close to the S30 Metal Shop layout. Until more evidence presents itself, we can only study our cars and use our imagination to figure out the order of the individual parts being clamped on and welded, but keep this build format in mind. I would bet the farm, it is not far off the mark. If anyone has any thoughts or anything that they would like to discuss, contribute, critique. etc., please do. Keep in mind most of my contribution is considered theory only until proven and I’m just having fun with this.

Edited September 12, 2009 by geezer
corrected structure of post

[Zs-ondabrain]

I've actually done the "Mental Tear down and rebuild" in my mind many times but this really helps put things into perspective.

I do my best learning while "Having Fun" Keep it up.

Dave

[Bonzi Lon]

My theory on chassis numbers.

I think the numbers were put on after quality control checked everything and it was good to go to the paint department. Numbers being assigned and stamped upon leaving Q.C. and off to paint. If the shell was out of quality the 'cookie jar' shell could be inserted without loosing a chassis number or floor speed. The out of quality shell would be taken out/off, repaired or scrapped.

Bonzi Lon

[geezer]

My theory on chassis numbers.

I think the numbers were put on after quality control checked everything and it was good to go to the paint department. Numbers being assigned and stamped upon leaving Q.C. and off to paint. If the shell was out of quality the 'cookie jar' shell could be inserted without loosing a chassis number or floor speed. The out of quality shell would be taken out/off, repaired or scrapped.

Bonzi Lon

For the longest time I was convinced the number was stamped on the cowl in sub-assembly before becoming a part of the shell. One of the reasons I was stuck on that opinion was that I couldn't see how the number could have been stamped without a solid backing. I was trying to imagine how this could be done on a completed shell.

What I discovered, (and I would like to hear what others have found) is the number on my car wasn't stamped at all. It was engraved on. I studied it under magnification from both sides. From the backside you cannot see any evidence of the number being stamped. Looking at the numbers under the magnifying glass its easy to see the metal was carved out and not stamped. I would have loved to see this when it was done. I'm left wondering what the equipment used looked like.

Other than that, I'm now a believer in your theory Bonzi. What you describe is totally logical to me.

Edited September 12, 2009 by geezer

[Bonzi Lon]

Very interesting that it is engraved not stamped.

Engraving would not be hard at all. Having been in the jewelry business for life, we know if it can be held down, we can engrave it, even the insides of rings.

A small rotary bit engraver, or diamond point stylis, that would fit over the cowl and clamp down in the proper position. Place the proper font/numbers in the machine. It works off a pentagraph that follows the master type and the rotary head, or diamond point will make the same image on the cowl, but smaller.

This is all speculation.

Bonzi Lon

[Zak's Z]

Very interesting, Ron. I went out and studied my bare shell with this chart in mind, and I can see where the big pieces were joined. I had a look at my firewall VIN and can't see any marks that would be associated to a 'force' being applied. No bends, nothing pushed in.

[hls30.com]

I'll have to get the stripper out and check one of my shells-cool!

Will

[26th-Z]

I am glad to see you bring this subject up again Ron. I am absolutely fascinated with the design and construction engineering of the S30. The sophistication of the chassis construction for the period is remarkable in my opinion. Now you bring to light the idea that the VIN was engraved in place - very interesting.

I think I have posted these pictures from the collection before, but these may help illustrate.

I first became interested when I picked up this photo of a complete floor from an eBay sale years ago. Then I started collecting pictures of the various metal stampings and repair parts from eBay ads. These, I assocated with the exploded diagrams and illustrations in the parts books to examine various assembly ideas. On a bare chassis like 26th was once, you can see the assembly welds contrasted with the fabrication spot welds. Then you and I got into that long e-mail discussion, Ron, and I collected some photos from Nissan corporate annual reports. This is a great subject!

Edited September 12, 2009 by 26th-Z

[geezer]

Thanks for taking a good look at the chassis number Zak. Eventually we will get feedback from examples across the S30 timeline but that will take while. Unless the paint is chemically stripped, which mine was, at the time I noticed this, it could be tough to make a determination. I know Will is going to check a few and this is just something of interest to look for at the opportune time during a restoration or perhaps when a car is being parted.

The illustrations, pics, sketches, etc. are great Chris and they sure fuel the imagination. Everyone looks at these and comes away with a different idea of what they are looking at and I hope the explanations I shared, shed a little light on the subject. I have opinions and my skewed North American views of how these cars were constructed but not much in the way of tangible proof. I suspect we will always have unanswered questions.

As you know this Metal Shop flow chart was originally used for another purpose but should help us determine the order of assembly. It is actually only a matter of identifying all of the stampings that belong to each of the different lines, then determine the logical order of assembly. We also have to keep in mind that each of these lines have sub-assembly feeders. Many of these assemblies are spotwelded together using pedistal spot welders offline, (as you noticed when you were looking at Her Majesty the 26th naked) then clamped & welded in place on the line. The parts catalogs have some great illustrations that can help but I noticed they can also throw a few curves.

I haven't given this study much thought lately and my line of thinking was, if this thread was started, more input from those interested sure can't hurt and may get us thinking about it more. I really don't care how "off the wall" anyone might think their questions or ideas will be taken, throw them out here.

I am going to review my notes and then start line by line describing how I think this build was done. I find it difficult though to keep what happened in Japan all those years ago seperate from my own knowledge and experiences here. The similarities are uncanny.

PS - Chris, it's been a while since you mentioned the upright support bracket on the inside of the rear panel. Remember you said every Z made had a vertical strip there that was void of paint. I keep forgetting to tell you what I think it is. Going through the Paintshop every car had a heavy ground cable clamped from that general location to the body cart it was riding on. A safety precaution I've seen in every plant I've been in. It's located there for ease of attaching & removal. If I'm wrong about that, the only other thing that comes to mind, would be a temporary hatch support?

Edited September 12, 2009 by geezer

[Zak's Z]

I'll have to get the stripper out and check one of my shells-cool!

Will

Whoa whoa... lets not get too crazy here! Ron, look what you've done!

I cleaned mine off with both sandblasting and wire wheels so theres no chance of me noticing any engraving artifacts. I can say for certain there is no evidence of stamping (although its been painted). There would be a slight 'rise' at the edges of the numbers where the metal would have pushed up (bulged) outside of the stamp.

[Bonzi Lon]

Engraving over Stamping = Protection from Counterfiting.

After looking at both my Z's VIN's under a 10X loupe they appear to have been engraved with a rotary head and small bit. Each character is perfectly spaced and cut into the metal at the same depth, however an unusual font was used. Look closely at the 'H', 'L' and '0' (zero's). The 'H' has a wavy left leg, the whole 'L' is unusal, and the 'zero' has a funny top. "If" each company had 'their own font', copyrighted, registered with the feds, it would be hard to copy. Making a counterfit die for stamping is easier than one for engraving, if your that bent on it.

Now look at your block numbers. Under the same loupe, on the CC pad, (L24-L26) these have been 'stamped' using the same font as the VIN, only smaller and fairly straight in line. All 3 blocks have the same font for 'L & 6', hand struck, I don't have a 2 or 4 for compairson of the cowl font. The pad that has the numbers on it are smaller than the CC pad and more of the industry standard, definetly hand struck and not as evenly spaced.

I tried to find a VIN on the 68 Roadster for compairson but couldn't find it other than the aluminum plate. Any idea where it could be? Any other Datsun before the Z have this type and style of engraving over stamping?

Bonzi Lon

[geezer]

It is unanimous up to this point with 5 VIN numbers being studied closely. Unless we have someone come forward with evidence of their chassis numbers being stamped, I think it is safe to say they were engraved. I agree on the specialized font that was used. It is unique and not easily reproduced. I did notice though, on my car the numbers are not spaced perfectly and are not positioned evenly horizontally either. Not a very good pic, but if you look very closely, you will also see a small symbol before the last digit of "0" that is engraved also. Wonder what the significance of that could be? It will be interesting to see if there is a master pattern that develops with different number progressions when we compare these.