1981-c3 Gas Cap Correct

[Tom R.]

Re: 1981-c3 Gas Cap Correct

I've always thought of a theme that would have broad appeal would be to differentiate late model C3 from early model C3 but don't know that I have enough content...would have to think through this. For example...four-speeds, gas caps, build sheets and I'm sure there are other items but just have to think thru what they would be. Oh yeah...convenience options!

Build sheets seems to gather interest and would cover 73-82 and even thru C6. But I'm differentiating manifests from Corvette order copy associated with 67-72 and discounting anything built in BG since they are readily available. Build sheets, broadcast codes and part images is a nice package to paint a picture of the assembly process. I probably have enough late model to illustrate the relationships and send owners scrambling back to their Corvette to dig through their stuff.

Frankly, I think the org training is heavily accented on C2 early C3 but than late model C3 group hasn't stepped up with the kind of content that fellow C3s would find of interest. This is a topic Freddie and I have talked about over the years. And while the numbers are down for 73-82...may be now is the time to venture into expanding tech sessions to address these model years...more later.

[Edward M.]

Re: 1981-c3 Gas Cap Correct

Joe Lucia said: It was a cap with a METAL top with an "ear" (i.e. raised finger-hold). The top was zinc plated with a chromate (i.e. "gold") overplate. The perimeter of the cap had small "serrations" as an additional hand-hold. The metal was stamped "unleaded fuel" and there may or may not have been additional stampings.

I just checked the cap on my 3 owner, 82K mile 79 and found a cap pretty much like Joe described. Metal top with an "ear", "serrations", stamped "UNLEADED" (above the ear), 'GASOLINE ONLY" (two lines, below the ear), and 557232 (curved line below the word ONLY). The number 3166 is stamped on the "ear".

Any possibility this is correct for my 79?

[Joe L.]

Re: 1981-c3 Gas Cap Correct

Joe Lucia said: It was a cap with a METAL top with an "ear" (i.e. raised finger-hold). The top was zinc plated with a chromate (i.e. "gold") overplate. The perimeter of the cap had small "serrations" as an additional hand-hold. The metal was stamped "unleaded fuel" and there may or may not have been additional stampings.

I just checked the cap on my 3 owner, 82K mile 79 and found a cap pretty much like Joe described. Metal top with an "ear", "serrations", stamped "UNLEADED" (above the ear), 'GASOLINE ONLY" (two lines, below the ear), and 557232 (curved line below the word ONLY). The number 3166 is stamped on the "ear".

Any possibility this is correct for my 79?

Ed------


I think it's VERY, VERY possible it's the original cap. I have only found part number GM #557232 as listed for 1977 SERVICE. I haven't found it as ever used for PRODUCTION, but I think it was used for PRODUCTION. GM #557232 replaced GM #556389 for SERVICE effective November, 1977 and was itself replaced by GM #560524 in February, 1980. So, the period of its SERVICE availability very nicely coincides with the period that, if used in PRODUCTION, would have made it a candidate for use on 1979 Corvettes.

Here are the caps that GM says were used in PRODUCTION for each of the 1975-82 model years and a brief description of the ones I have such info for:

1975-----GM #419862----unknown description

GM #419863-----unknown description

GM #7470051----zinc plated metal top with chromate overplate "ear", "NDH"

1976-----GM #419862-----unknown description

1977-----GM #556389------same description as 7470051 except for
stamped part number

1978-----GM #447998------unknown description

GM #559346------zinc plated, convex metal top with chromate
overplate; no ear, "NDH"

1979------GM #559346------same as above

1980------GM #559346------same as above

1981------GM #559346------same as above

1982------GM #22510715----polished stainless steel metal top; no "ear",
"NDH"

I have attached a photo of an NOS example of the GM #22510715. Anyone ever seen one of these on an '82? The box that this piece was packaged in is dated 1981, so this is an original configuration piece.

Based upon what's been reported already in this thread, we haven't come up with a 1980, 1981, or 1982 Corvette yet that has the cap that GM says was originally installed. While the GM information is usually extremely accurate, I think these 80-82 gas caps may be an exception.

[Terry M.]

Re: 1981-c3 Gas Cap Correct

Frankly, I think the org training is heavily accented on C2 early C3 but than late model C3 group hasn't stepped up with the kind of content that fellow C3s would find of interest. This is a topic Freddie and I have talked about over the years. And while the numbers are down for 73-82...may be now is the time to venture into expanding tech sessions to address these model years...more later.

You are right, but it is those who participate who dictate the content. We could debate if the late C3 participation is down because of the lack of content, or the other way around. And I don't have the answer to that.
Let's keep working on it. I am open to ideas.

[Tom R.]

Re: 1981-c3 Gas Cap Correct

Out of curiosity...I check the AIMs for the model years being discussed. I was curious if the cap was part of the tank assembly or listed separately. It was called out on the "fuel tank cap assembly" page. MY 75 is most interesting due to the number of caps called on on the AIM page which references option K72 which I suspect is an emission control item

1975 except K72 419862
1975 opt exc K72 419863
1975 opt exc K72 7470051
1975 & K72 419910
1976 - 419862
1977
1978 - 559346
1979 - 559346
1980 - 559346
1981 - 559346
1982 - 22510715

Conclusion...doesn't clear up anything except suggests why the judging manual takes a conservative approach to its guidance to judges for gas caps

[Edward M.]

Re: 1981-c3 Gas Cap Correct

Two things:

1. I know that 559346 was the cap on an original 40K mile 1977 car that a friend of mine used to have.

2. On the 557232 cap that I have, what is the 3166 that is stamped on the ear. Date code? There isn't anything on the inside of the cap that would indicate date. 316th day of 1976? If so, that would seem to imply that it would not be correct for my March 79 built Vette.

Yes I did double check, it is 3166, not 3168.

This is a fascinating topic. It desperately needs a Restorer article.

[Tom R.]

Re: 1981-c3 Gas Cap Correct

Two things:

1. I know that 559346 was the cap on an original 40K mile 1977 car that a friend of mine used to have.

2. On the 557232 cap that I have, what is the 3166 that is stamped on the ear. Date code? There isn't anything on the inside of the cap that would indicate date. 316th day of 1976? If so, that would seem to imply that it would not be correct for my March 79 built Vette.

Yes I did double check, it is 3166, not 3168.

Ed

Trust your instincts on this. Consider that part numbers were assigned sequentially so 557232 was assigned before 559346 which would tell us the 557232 cap is older than a 559346 unless of course the older is being phased out while the new is phased in. So the 316th day of 76 is consistent with sequentially assignment of part numbers.

I believe I've seen that 557232 cap before but the ear always tells me that that feature is consistent with early caps 75-77.

Can you post a couple of high resolution photos?

[Terry M.]

Re: 1981-c3 Gas Cap Correct

To state the obvious:
Gas caps are so easily changed, like radiator caps and filters, that it is difficult, short of one-owner cars, to be sure of the provenance of these items. I am not suggesting anything about the data provided in this thread. I just wish to point out the overall level of difficulty of what we are trying to accomplish.

[George C.]

Re: 1981-c3 Gas Cap Correct

Picture of one I have that came off my 1975 Corvette. Oct 74 delivery.

[Tom R.]

Re: 1981-c3 Gas Cap Correct

Picture of one I have that came off my 1975 Corvette. Oct 74 delivery.

Nice one thanks for sharing George. Do you have the build date of the car?

Interesting to note and compare the "serrations" around the outer perimeter of this cap. Compared to other 75 identified caps, this would appear to be an early 75 cap in contrast to others. I say that because the serration feature of other 75 caps seems a consistent feature through 80. Others?

PS...nice oak desk as well or should I say the grain.

[George C.]

Re: 1981-c3 Gas Cap Correct

Hi Tom, Thanks for the nice comment about my table. My Corvette was vin # 1Z37J5S402602. Received at St Louis for production on 10/18/74. I had to do some digging , but found some old paper work. lol.Hope this helps. Save the Wave.>George

[Tom R.]

Re: 1981-c3 Gas Cap Correct

Hi Tom, Thanks for the nice comment about my table. My Corvette was vin # 1Z37J5S402602. Received at St Louis for production on 10/18/74. I had to do some digging , but found some old paper work. lol.Hope this helps. Save the Wave.>George

Love oak! And that's a nice dark finish. I have a blonde oak kitchen table I finished in a walnut oak and the finish is similar...a bit off topic but it is on message with "restoration"

Is there any date codes on the revese side? I'm assuming the 235 4 is the stamped date code which would be consistent with your delivery date. On second thought, I would suspect that there is not date code and that 235 5 was the method of coding for the early caps. But than I'm theorizing in the absence of data.

[George C.]

Re: 1981-c3 Gas Cap Correct

Hi Tom, No other marks or part number on the cap. Just that 235 4 stamp in ink. >George

[Alger R.]

Re: 1981-c3 Gas Cap Correct

How about my original 75 cap from April 2nd, 75 it has the numbers 599 0308. No other markings on inside or outside. No "Unleaded Fuel Only" Has the flat side with the tiny indents circling the side. Also an identical Dole Cap I have had with "Unleaded Fuel Only" but no numbers inside or outside. Very confused as to whats correct for 75

[Tom R.]

Re: 1981-c3 Gas Cap Correct

How about my original 75 cap from April 2nd, 75 it has the numbers 599 0308. No other markings on inside or outside. No "Unleaded Fuel Only" Has the flat side with the tiny indents circling the side. Also an identical Dole Cap I have had with "Unleaded Fuel Only" but no numbers inside or outside. Very confused as to whats correct for 75

Alger...what we are seeing here is that several are correct for 75 so don't doubt yours is not correct. Can you post some high resolution photos?