C4 hood date code etchings

[Peter M.]

Re: C4 hood date code etchings

Okay, here is a wrinkle for you. My 1986 C4 Pace Car has an etching on the inner convertible hatch panel. The Corvette arrived from the Bowling Green assembly plant with the following lettering scratched into the convertible top deck lid:

1 of 80 – 3/16/86

1 of 80 - a.jpg1 of 80 - b.jpg

[Rex M.]

Re: C4 hood date code etchings

Peter, The convertible hatch panel was produced by Budd Co. in North Baltimore, Ohio. I saw panels on the line at Bowling Green with tags such as these. It was their way of tracking, similar to what Gen Corp used.

[Joe L.]

Re: C4 hood date code etchings

Pat, I'm the guy who pointed out the etched dates on some hoods at the Florida Regional. Hoods made after about 1990 were made in Shelbyville, Indiana at Gen Corp Automotive. Assembly workers were instructed to put the date / sequence number of assembly / and shift. Thus a number like 10-21-91A would mean; Oct 21st, 91st hood assembled on 1st shift. The workers moved around on different jobs every shift. There were only two shifts; A & B. Sometimes they put it on hoods, and sometimes they didn't. Sometimes it was on the left, then right. Sometimes at the front and some at the rear but usually at the front. The dates were etched with a cheap electric etcher bought at Sears. If done properly Bowling Green could check dates to find if there were a bond adhesive problem on a certain date and on what shift.

Rex------

My guess would be that the last series of numbers (e.g. "91" in my example) sometimes referred to the year rather than the day's sequential build number. My hood would have been produced sometime around October 21, 1991. It just seems too coincidental that my hood, definitely produced in 1991, would also have been the 91st one manufactured on October 21. Also, it would seem that several other hoods reported on here have the last digits consistent with the year the hood would have been manufactured.

I do agree, though, that, from a quality control perspective, the month, day, sequential number, and shift would have been much more relative than including the year. Many GM castings, especially aluminum castings of the period, included only month and day with no reference to year. I've always figured that was because, within the time frame of concern from a quality control perspective, the year would have been known.

[Tom H.]

Re: C4 hood date code etchings

Here's an etching from a May built 96 Grand Sport.

[Rex M.]

Re: C4 hood date code etchings

Joe, With all the changing of workers on the hood assembly, exact instructions were not always given. This was the new "Team Approach". It didn't work and finally Gen Corp went bankrupt and sold to Cambridge Industries. They kept trying to use the rotating workers also. Then they went bankrupt and sold to Meridian Automotive. Workers if instructed correctly, were to scribe; Month, day, assembly sequence number and shift. Most of the time there was only one shift..."A", which they quit writing. But if you have a Vette with the correct inscriptions it should go along with the build date of the car. The date should always be a few days prior but never after the fact.

[Pat F.]

Re: C4 hood date code etchings

This certainly has been an interesting subject. I want to thank everyone who sent in their comments, especially Rex. All this information has been/will be passed onto Tom Barr and Allen Tremain, the National Team Leaders for the 84-96 C4's.
Looking at Tom Hendricks recent photo, it clearly shows the last two digits to be 45. According to Rex this would be the sequence number for the hood built that day. Also from what Rex told us, anything went, so you never know what type of etching you would get, or none at all.
In all the examples that we have gotten, only Joe's had the letter A. This is the earliest example we have.
Procedures and instructions what to place on the hoods probably changed a lot in all the changes in management.
The good thing is that we somewhat understand another mysterious marking on our Corvettes.
If anyone else wants to send in information I would be happy to receive it and then pass it on to Tom and Allen.
Again, thanks to everyone who sent me STUFF.

[Pat F.]

Re: C4 hood date code etchings

Rex, another question that I thought of pertaining to this matter was:

Did your company install the wheel splash panels that were attached underneath the hood? Meaning did you supply a complete hood?

I just received another etching from John Marsico who has a well documented 1992 and he has the shift indicator and the date code is month day and year and shift indicator - A. Looks like the early models show the shift indicator.
John is going to post the photo to this board and I thank him also.

As of now all the information that you folks have posted to this board have been forwarded to Tom and Allen.
Again, thanks for your help.

[John M.]

Re: C4 hood date code etchings

Pat, Sorry for my delay in resp92 Hood Date Code 4.jpg92 Hood Date Code 6-15-92A.jpgonding to this thread and my tardiness in posting the photos of the etchings on my 6/92 LT1 Coupe's Hood. The etching appears to be 6-15-92A. The work is consistent with Rex's description of the inexpensive Sears tool. Thank you Pat for all your work on the C4 database. Your efforts have been so very helpful to all of us. John

[Rex M.]

Re: C4 hood date code etchings

Pat, No GenCorp didn't supply that upper wheel housing as it was made from RIM not fiberglass. We did supply the lower wheel housing and from 1990 on there was no juliene date or anything on the lower. Before 1990, you may see the little white ticket molded into the part. It would be on the back side where you couldn't see it. The upper housing was installed on line at Bowling Green.
Rex

[Joe L.]

Re: C4 hood date code etchings

Joe, With all the changing of workers on the hood assembly, exact instructions were not always given. This was the new "Team Approach". It didn't work and finally Gen Corp went bankrupt and sold to Cambridge Industries. They kept trying to use the rotating workers also. Then they went bankrupt and sold to Meridian Automotive. Workers if instructed correctly, were to scribe; Month, day, assembly sequence number and shift. Most of the time there was only one shift..."A", which they quit writing. But if you have a Vette with the correct inscriptions it should go along with the build date of the car. The date should always be a few days prior but never after the fact.

Rex------


By the way, I'm always extremely interested in learning the manufacturer and manufacturing location of Corvette components. So, thanks very much for providing that information.

A predecessor operation to Gencorp has a very large place in Corvette history. A. O. Smith/Dow-Smith Corporation operated a plant in Ionia, MI which served as an alternate source for complete Corvette bodies during much of the C2 period. I believe some body panels were also manufactured there. Later, the whole operation was sold to Gencorp which continued to manufacture fiberglass components and body assemblies there. I went by about 20 years ago and they were manufacturing fiberglass hoods for Lincoln Mark IV as well as complete rear body sections for Ford stepside pick-up trucks.

The Ionia factory was a huge, old-fashioned, multi-story brick building. Sadly, it's gone now having been demolished several years ago. I'm glad I saw it while it was still standing and in operation.

[Pat F.]

Re: C4 hood date code etchings

Rex, again, thanks for your help. The upper wheel housing made of RIM material that you mentioned might have been supplied by a company called RIMPLY. I wrote an article for the Restorer Magazine (Volume 37, Number 4, Spring 2001) in which I was advised by John Hinckley that the fascias were made of the reaction-injection-molded (RIM) urethane. These items were manufactured by RIMPLY and shipped to Bowling Green. Lots of good markings on these items.
See the photo of the RIMPLY sticker that started it all.
I would appreciate it if you would contact me at fulassoc@comcast.net. I wanted discuss other related items on this matter. I have been asked to write an article on this matter for the Restorer Magazine.

[Ed H.]

Re: C4 hood date code etchings

OOPS, my bad. I should have checked the drivers side of the hood. My 90 has an etching low on the front of the hood, near the head light.
I can see a large letter A at the end of the script. The rest of the etching I am unable to decipher, old eyes I guess. I will show Tom Barr or one of the chassis guys, of the location, at the Arizona Regional next month so it can be examined and noted for the record. My build date is 4/90.

[Pat F.]

Re: C4 hood date code etchings

Ed, thanks for the information. Your identifying the A at the end of etching goes along with what we have seen in the early C4's so far. This letter identifies the shift.
Tom Barr was shown these etchings at the South Florida Regional in Lakeland and at his request we started this inquiry.
Tom will know exactly what you are talking about when you show him the etching on the right side of your hood.
I have a couple of matters going with him right now and I will advise him of your post,
Ed, if at all possible could you take a photo and send it to me at fulassoc@comcast.net.
Thanks

[David H.]

Re: C4 hood date code etchings

Pat,

No hood date etching on my son's June 1996 coupe.

Dave

[Rich C.]

Re: C4 hood date code etchings

Pat,

I earlier reported no etching on my December '96 collector edition. After a 2nd look with better lighting...indeed it is there! Very faint but there is one there after all! Sorry for the mis-info! 11-30-5

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1996 LT-4 CE coupe
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