How close dose the date code have to be to the build date of the car?

 

I'm no expert, & I'm going by my April 1968 built Cutlass, but it kinda depends on what part.
Prebuilt assembles like trans, diffs, engine components, etc.. seem to be ~ 6-8 weeks ahead of build date.
Some suspension & body pieces were about 2-3 weeks ahead.

Some things were made in batches so a certain date could cover a couple of months of cars.

 

To accomplish what? Proof of the numbers-matching-ness of the car? The build date itself is only a month/week, anyway, right? There's no way to pinpoint the exact date a car was built, at least that I know of.

 

Unless the week only has 1 day !

Mine is 5th week April 68. Tuesday was April 30, so it was built either 29th or 30th.

 

Not necessarily. I would guess that the "weeks" were Monday through Friday weeks regardless of how many days of a particular month fell in a particular week, and the "month" of the week would be whatever month the day that started the week was in. So the "first" week of any month is the first FULL week of that month, or, in other words, the week that contains the first Monday of the month.

So May 1, 2, and 3 (Wednesday, Thursday, and Friday) of 1968 were actually part of the last week of April, not the first week of May, because Monday of that week was still in April, and the "first" week of May 1968 was actually the week that began on Monday, May 6. I don't actually know that any of this is the case, but this is the way I've always interpreted these month/week date codes.

It's actually much simpler as all months begin on a Monday. Otherwise, you'd have every month beginning on any day, and that's much more cumbersome to keep track of. In one particular month, if the 1st was, say, a Thursday, that means the week would end the next Wednesday, and week 2 would begin on a Thursday. In a different month, the 1st could be on a Tuesday, so Monday of the next week is actually the last day of the first week, and Tuesday is the first day of the second week, and on and on for every month with every month being different. It would be a royal pain in the *** to keep track of, and I'm guessing that the manufacturers didn't do it this way.

 

From the original parts on my '68 4-4-2 convertible (Lansing car) with a build date of the first week of April 1968 (04A), the parts can vary from just a day or two, to nearly six months. For instance, the original block on my car is dated "304", or November 1, 1967. That's 5 months before the car was built. I have a friend with a Lansing '68 4-4-2 convertible whose build date is 04C and the original block in his car is dated just a couple of weeks before his car's build date.

On the other hand, the steering box on my car is dated April 1, 1968, and the box cover is dated April 4, 1968. Those two dates represent the production date of 04A on my trim tag.

I say that, in general, if a part is dated within 6 months of the build date of the car, that would make the part valid if you are looking to do a "numbers correct" car. But there are even exceptions to that. If a car is a rarer production (Hurst Olds, W30/31/32, etc.) you might find parts that are older than 6 months before the production date on the trim tag.

Just my 2 cents worth.

Randy C.

 

X2^^

On my W-31 the oldest component was the original mufflers that are 4 months prior to the build date. Most of the components are within 30 days.

 

I don't think that is completely correct. Where i work we deal with a 52 week calendar (Billing cycle). This year January had 4 weeks, February had 4 weeks and this month has 5 weeks. This month started on Monday but it was February 25th. The last week will end March 29th. About like a pay check, My first day of this year is December 28th because the 27th was the last pay day of last year.

If you had a car built the first week of November 69 could it have been built from October 28 to November 1 or would it have to be built on November 1st and no other day? If the first week didn't start till November 4th (first Monday of the month) that would eliminate the 5th week of November and i have a 5th week of November car. I don't know if that was how GM did it or not?
http://www.timeanddate.com/calendar/...969&country=23

 

I see your point. I really don't know what the Oldsmobile calendar situation was. It would be interesting to find out.

I can correct one thing, though. You've posted a link to the 1969 Julian Calendar. The correct calendar is the Gregorian Calendar, which is what is followed in the U.S. and is slightly different.

http://www.timeanddate.com/calendar/...1969&country=1

 

My experience has been that cast pieces can be months ahead of the build date. Parts like Muncie trans,starters,alternators,voltage regulators can be within days of a build date. My 66 block has a 307 date and a build date of 02D. That's basically 4 months out. My theory is when they cast parts,they go into a holding room/building with the earliest parts in the back. The newest parts toward the front and when needed,the parts in the front are used first.

 

I goofed up also on my car. It was October 5th week and not November.

 

This is a great topic. It appears that GM used a calendar week for the fisher body tags. However, you will have split weeks as mentioned in most of the months. Now, if you have your broadcast card, then you are in luck when your car was built by fisher. Also, another point to consider on dates is automation. I am sure automation improved lets; say from 1964 to 1972 and depending on the number of shifts that were working. Also, think items may have a casting date and then assembly date. Example: the rear ends are as such except for the W-27s. Again, good topic.

 

Things like voltage regulators and alternators were stamped when they were made not the car, so if you have a Arlington or Fremont car, there is no way those parts could have been made days before your car. They had to be made, shipped hundreds of miles, then installed. Id bet plants like that had huge floats to guard against running out.

Lansing was probably the same, but since the engine plant was local and the delco plants were a days drive, parts could and were dated closer to the cars build.

I was cleaning up the intake off my club coupe last night and the cast date is 345. Car was built third week of Dec 1964. Intake was probably still hot when it was bolted on.

Alternator is dated Dec 2.

 

Our transmissions at work go to the dock. They sit waiting to be loaded onto trucks to shipped out. A lot times they get put on hold to be rechecked, so newer built transmissions can and do get shipped out before older ones. Also, if we run out of certain parts we will build other models that we dont need to stay running. Those will sit until needed.

Im going to guess Olds would build a bunch of 400s all at the same time. But they didnt build a bunch of 442s at the same time. They picked the 400s as needed.

 

See,nobody wanted a 65,so the parts were date coded closer to the build. Now,with the 66's being so much popular & better looking,the date codes were farther apart.

 

65
25,003

66
21,997

 

Damn,that hurts.

 

You guys are funny.

Good discussion.

 

...and that's what makes this site so great!

Randy C.

 

I have a '68 W34 Toronado engine that has a casting date of 78 (March 18, 1968) with the car having a build date of 03D (fourth week of March.) Was this enough time from the cast date for the engine to be machined and installed into a car on the production line? BTW, this car has one of the rare forged cranks in it.

 

Thank you and all of the others who have served our Country,especially those who paid the ultimate price on this Memorial Day.

 

It's close but I believe it works. Like I said for my car, the steering box and cover are dated the very same week as the build date of the car. I'm not an expert in engineering or machining, but I believe that if they needed engines for cars on the assembly line, that they would be made available. And, with the VIN code on your engine block matching your VIN, there is no doubt the block is original to the car.

Randy C.

 

The block in my 69 is original and dated 115 which was a friday and the build date is 04e so my engine must still of been warm

 

^^ This ^^

I've never heard of a 're-stamped' engine VIN derivative. I supposed it might have been done in shady cases of high dollar rare 'numbers matching' resto'd cars, but very doubtful for regular cars. If the block was a service replacement (i.e. the original owner blew it up and had it replaced under warranty), it would not have a VIN stamp at all....just a blank/bare pad.

Don't remember the date on my '68 350 block, but other parts were dated
within 2 weeks of my 04E build date.

 

Something to remember - the Fisher Body "tag" has the assembly week for the body, not the car.

In another thread it was suggested (regardless of year/month/etc.):
01A = 1st-7th
01B = 8th-14th
01C = 15th-21st
01D = 22th-28th
01E = 29th-end of month

The "short" E-week would explain why there are so few "01E" tags.

I'll plug some info I have into the above 52-week theory, but I already have questions how 12 months and 5 weeks (A,B,C,D,E) & leap year would play out there.

 

Also, Toronado bodies were "built" at Fisher Body "EUC" Euclid, Ohio - so the body had to be shipped (I'll "assume" by train) to Lansing for final assembly. The engine only had to travel across the "plant".


FIFO - "first in - first out" inventory controls were NOT in use.

 

What about strikes and other shutdowns ?
A car body that was assembled the 4th week of April may have sat for three months on the line while the strike was settled.
When production resumed in July the car may have been completed with components that were made in the same week.
So called "experts" would say that such a car could not be "correct" with components built after the so called "build date". and yet the car would be totally original.
I think that this business of "matching date coding" is ridiculous and a waste of time and in some cases money.
IF THE PART IS THE CORRECT ONE SPECIFIED FOR THAT YEAR MODEL OF CAR IT IS CORRECT! Date codes be damned!

 

I went and looked
I don't see the difference between the Julian in the link

http://www.timeanddate.com/calendar/...969&country=23

and what we use.
One starts on TU, other on WED.... how can that be?
??