St. Louis Plant Assy Time Study

[Michael H.]

It may sound totally unrealistic to all of those who restore their own cars but here's an amazing bit of trivia from the St. Louis assembly plant.

From the exact moment an absolutely bare frame is placed on the frame buck at the beginning of the "chassis conveyor" to the moment a worker turns the key for the first time and starts the car is just about exactly 196 minutes.

That includes installing all of the suspension/steering, differential, engine/transmission, brake/fuel lines, a complete painted and partially trimmed body, wheels/tires, fuel tank and exhaust etc etc.

From a bare frame to something that runs and drives in a little over three hours!

Granted, these times were from the late 70's and early 80's and would be slightly different than 63 to mid 70's but it still gives some idea of the speed at which these cars were assembled.

Michael

[Eugene B.]

Re: St. Louis Plant Assy Time Study

Michael,
Pretty amazing piece of information. If we could find out how many people worked on the assembly line, then we would know many man-hours it took to produce the car.

Although, when assembling a new car they had the advantage over us restorers since they were receiving many sub-assemblies and completed items and all they had to do is bolt them on the car.

It's still interesting that we spend between 1000 and 2000 hours to restore an automobile that someone else spent a little over 3 hours to build in the first place.

Thanks again for the info, Michael. Interesting and fun data.

Best regards,
Gene

[Jim T.]

Re: St. Louis Plant Assy Time Study

How long was the primering, painting, baking, and finishing out the exterior paint on the C2's and C3's?

[john daly]

Re: St. Louis Plant Assy Time Study

I don't think looking at the process from when the frame assembly was started gives the whole picture. There was lots of assembly and subassembly already completed in St. Louis on the engine and body by that point. On an A.O Smith car the body was essentially complete weeks before the frame started down the line in the chassis department.
I read in one of the books about St Louis that that Paint was set up for 250% of production. That means each car can go through the paint shop including repair 2.5 times and they could still maintain regular production.

[Michael H.]

Re: St. Louis Plant Assy Time Study

John,

You are correct. It doesn't give the whole picture. Not even close. I chose to narrow it down to just one segment of the entire car assembly and I thought the chassis build/body drop would be the most interesting.

The body build, prime and paint was by far the longest operation of all and it was started several hours before it's matching frame or engine had even been pulled into the line. The many prime/paint operations required the body to make several loops through paint, then bake. At least three passes through the oven were required before the paint was complete. I don't remember the exact time but I would guess about eight hours or more on just the body assembly and paint before work started on the chassis.

Roughly the same time, or slightly after, the chassis went on line, the engine was pulled from stock and it started on it's way down the engine dress line. That would be about the same time that the body was rolling out of it's last paint reflow oven.

Michael

[John H.]

Re: St. Louis Plant Assy Time Study

That pretty much squares with my old notes. The outer aisle at the east end of the building was about 400' long, and the frame/chassis/pre-final line to Roll Test was a little longer than that wall (and ran perpendicular to it). Job spacing (except on the short frame upside-down line) was on 20' centers, and line rate was seven per hour, for a chain speed of 2.3 feet per minute (nearly stationary compared to a typical assembly plant at 22 feet per minute). At seven per hour, 196 minutes is 3.26 hours x 140' per hour, or a conveyor length of 456 feet (23 units/job stations) from the frame line start to car start. Assembly plant direct labor time study job loading standards in those days were generally around 85%-90%, so the total transit time for 3.26 hours of applied (studied) direct labor would be closer to 3.5 hours, or conveyor length of 500 feet, or 25 job stations for those operations.

Trim, Chassis, and Final assembly was pretty conventional from a process perspective; the Body Shop and Paint shop were not, and were extraordinarily labor-intensive, with pitifully high rework/re-process and repair rates. "Nature of the beast"

[Sydney G.]

Re: St. Louis Plant Assy Time Study

Michael,
How many paint stations did they have running simultaneously for 63-67?
Were the bodies coming down the assembly line divided into two paint stations for priming and then painting? Or, divided into four stations etc.?
Syd

[Michael H.]

Re: St. Louis Plant Assy Time Study

John,

I think your calculations are accurate. The Chassis line and final line may have been a bit longer. I have the "final line" (after touchdown)at exactly 220' with 12 jobs @ 15'6" centers. I don't have a length for the chassis line (before touchdown) but it held 14 jobs @18'0" centers so the chassis line would have been probably near 300'? Also, I forgot to add the job at the body drop location in between chassis and final line. That would be a total of 27 jobs from beginning to end.

Near the end of production at that facility in 1981, the speed increased to one job in just over six minutes. (6:07 if I remember corrrectly)

[Michael H.]

Re: St. Louis Plant Assy Time Study

Syd,

Very confusing but basically, there was only one line. The bodies came out of the "body grind" booth and entered the one lane first prime/color booth. (called "prime and first coat Lucite spray booth") From there, they entered the 2nd booth that had four runs, or four different tunnels. The first time through, a body went through one of the two "prime lines" and then out the end where it changed direction and returned to the first booth. (confused yet?)

Back through for first mist color coat. Then out of "Prime and First Coat" to the 2nd booth and "prime and 1st coat oven". Around again to the "wet sand deck" and then back in the beginning of the 2nd booth for final color.

I can try to post a drawing showing all the routes if I've confused everyone.

[Michael H.]

Worst Drawing on the Internet

Not exactly blueprint quality but I was in a hurry. Hope this explains it better.

[Sydney G.]

Re: Worst Drawing on the Internet

Michael,
What a scrawling!!
O.K., so you are saying that there were two paint booths, or stations, where the serial sequence was divided, or seperated.
I always wondered how they ran the change of colors, or job orders.
Were the c2's painted in batches (2-10) of Riverside Red for example, or just as the orders came in?
How did they alternate between colors so quickly without holding up the line?
Syd

[Michael H.]

Re: Worst Drawing on the Internet

The colors were random and new car orders were produced as received. If the paint color operation was done using a conventional siphon/cup spray gun, this could/would be a problem as some colors were used less than others so the gun and paint in the cup would sit for quite a while. The system that most automobile mfg's use instead is called a pressure feed recirculating system. There's no cup on the gun at all. Instead, there are two paint material lines attached to the gun, one flowing in and the other flowing out back to a reservoir or pot. The material is constantly circulated, pumped through the system to the gun and back so the material is constantly stired. Slightly restricting the return line at the return port would raise the pressure at the spray nozzle.

On hooks on the wall of the paint booths hung several different spray guns, one for each available color that year. As soon as a body was painted and moved out of the booth, another moved in and the operator picked up the correct gun/color.

I know someone will ask if ever a painter on one side had begun to spray with an incorrect color, different than his partner on the other side. I've heard stories but never was able to document any. I would have to guess that it happened at least a few times over the years. Years ago, I saw a pic of a new F--d Pinto that had been painted one color on one side and a different color on the other. This would have been well into the age of automation so I suppose it's probable that it happened because of computer or operator error.

[Wayne W.]

Re: Worst Drawing on the Internet

Michael, When I was in the plant 1-7-76 it looked to me that the painter used the same gun for every car, but he just plugged it into a different paint feed. I watched them stand and spray through the floor grating untill the color flushed from the gun. Also, I once stripped a silver `72 that was definitely original paint. Under the silver was a coating of steel cities gray. Obviously it was done the wrong color in the first painting, but was corrected at the final.

[Michael H.]

Re: Worst Drawing on the Internet

I wonder if he wasn't just switching guns because one was not performing properly? I'm not 100% sure if each color had a unique gun in the 70's but I know they did in the 60's. I'll try to dig out some info on this.

That Steel Cities Grey 1st coat is interesting. Bet there's a lot of cases like this.

[John H.]

Re: Worst Drawing on the Internet

It paid to be an industrial plumbing contractor (or pipe manufacturer) in the 90's when the OEM's went to waterborne basecoat to comply with EPA VOC regulations; all assembly plant paint circulating systems (THOUSANDS of feet of pipe for each color, from the central mix room to the color booths and back to the mix room) had to be replaced with stainless steel, along with all the valves and pumps. "Big Bucks" hardly describes this expenditure, which was equaled by the massive booth high-velocity downdraft air management systems required to maintain booth temperatures within two degrees and booth humidity within 2%, which was the required "control window" for waterborne paints. An assembly plant Paint Shop is the most expensive real estate on earth; $400-$600 million for a typical new Paint Shop these days (maintained under positive pressure with airlock entry doors, and as clean as a hospital operating room)