1981 Corvette Gas Cap

[Chuck G.]

A friend just bought a pretty nice 81 earlier today. I ran into him this evening. Sounds like a pretty original car with about 78K miles on it. He showed my some cell phone pix of the exterior only.

He had concern about 2 gas cap issues.

1. The cap is white.
2. He wasn't sure if the cap should be vented or non vented.

I'm no late C3 guru, but I believe that the white cap is correct, appearance wise.

I also "think" that the cap should be non-vented, as this car apparently has all the emissions/smog stuff still on it.

So.... Should the cap be vented or non vented?

Is the white plastic cap correct?

TIA

Chuck

[Joe L.]

Re: 1981 Corvette Gas Cap

A friend just bought a pretty nice 81 earlier today. I ran into him this evening. Sounds like a pretty original car with about 78K miles on it. He showed my some cell phone pix of the exterior only.

He had concern about 2 gas cap issues.

1. The cap is white.
2. He wasn't sure if the cap should be vented or non vented.

I'm no late C3 guru, but I believe that the white cap is correct, appearance wise.

I also "think" that the cap should be non-vented, as this car apparently has all the emissions/smog stuff still on it.

So.... Should the cap be vented or non vented?

Is the white plastic cap correct?

TIA

Chuck

Chuck------


Attached is a photo of a known-original 1981 Corvette gas cap. Was every one ever installed on a 1981 exactly like this? That I do not know.

All 1970 and later Corvette gas caps were non-vented.


DSCN2893.jpgDSCN2894.jpg

[Terry M.]

Re: 1981 Corvette Gas Cap

A friend just bought a pretty nice 81 earlier today. I ran into him this evening. Sounds like a pretty original car with about 78K miles on it. He showed my some cell phone pix of the exterior only.

He had concern about 2 gas cap issues.

1. The cap is white.
2. He wasn't sure if the cap should be vented or non vented.

I'm no late C3 guru, but I believe that the white cap is correct, appearance wise.

I also "think" that the cap should be non-vented, as this car apparently has all the emissions/smog stuff still on it.

So.... Should the cap be vented or non vented?

Is the white plastic cap correct?

TIA

Chuck

Chuck,
There is a date code (of course, what would one expect) on those gas caps. Around the circumference, just above the threaded portion -- close under the cap part. I can nto remember the sequence, but the code will be obvious once you find it. Small letters and numbers about the size of the code on the turn signal flasher.

Of course if the code looks correct for the car, well, if it walks like a duck and quacks like a duck -- and on and on.

[Joe L.]

Re: 1981 Corvette Gas Cap

Chuck,
There is a date code (of course, what would one expect) on those gas caps. Around the circumference, just above the threaded portion -- close under the cap part. I can nto remember the sequence, but the code will be obvious once you find it. Small letters and numbers about the size of the code on the turn signal flasher.

Of course if the code looks correct for the car, well, if it walks like a duck and quacks like a duck -- and on and on.

Terry------


I can find no code on the one I pictured. Of course, if it was printed rather than embossed it could have deteriorated.

[Tom R.]

Re: 1981 Corvette Gas Cap

The date code in this photo is a a 1980 cap. It shows the format (day/year) and what to look for (embossed numbers).

1980capdatecode.pdf

[Chuck G.]

Re: 1981 Corvette Gas Cap

Thank you for all the information. I'll pass it on to my bud today. I'm sure he'll be playing with his new toy.

Chuck

[Terry M.]

Re: 1981 Corvette Gas Cap

The date code in this photo is a a 1980 cap. It shows the format (day/year) and what to look for (embossed numbers).

[ATTACH=CONFIG]48056[/ATTACH]

Tom,
That is not the one I remember Brian showing me, but then maybe he showed me a different year. The one he showed me was located as I described and is indented into the plastic, so it would be there for life.

[Chuck G.]

Re: 1981 Corvette Gas Cap

I copied the pictures, then sent those pictures along with the date info y'all provided to my friend earlier this AM.

Haven't heard back yet. I'm sure he'll be playing with his new toy all day today.

Chuck

[Joe L.]

Re: 1981 Corvette Gas Cap

The date code in this photo is a a 1980 cap. It shows the format (day/year) and what to look for (embossed numbers).

[ATTACH=CONFIG]48056[/ATTACH]

Tom------


Do you have any other photos (e.g. top) of this cap?

[Tom R.]

Re: 1981 Corvette Gas Cap

Do you have any other photos (e.g. top) of this cap?

Yes

80cap.jpg

The one he showed me was located as I described and is indented into the plastic, so it would be there for life.

Like this? I picked this OTC SERVICE replacement cap this summer cheap dated 712 or 71st day of 1982. The original boxes carries GM# 22525300. It has the S for Stant but color is black vs OEM that were white for this period.

DSC03626.jpg

[Chuck G.]

Re: 1981 Corvette Gas Cap

My friends was shocked to learn the the white cap was correct. He figured it was some Pep Boys aftermarket product.
I did direct him to the NCRS site and told him about the JG's etc. Don't know if he wants to go that route, but the manual contains a wealth of info about the car.

Thanks again to all.

Chuck

[Joe L.]

Re: 1981 Corvette Gas Cap

Yes

[ATTACH=CONFIG]48068[/ATTACH]



Like this? I picked this OTC SERVICE replacement cap this summer cheap dated 712 or 71st day of 1982. The original boxes carries GM# 22525300. It has the S for Stant but color is black vs OEM that were white for this period.

[ATTACH=CONFIG]48069[/ATTACH]

Tom------


Yes, the 22503147 is configured as I would expect. This goes to show that the caps specified in the AIM were not always the ones actually installed. For 1979 through 1981 the AIM's specify cap GM #559346. The P&A catalogs show the 559346 for 1979. However, the GM #22503147 is shown in the P&A for 1980 and 1981. Both the 559346 and 22503147 are very similar caps. Both have a convex steel cap with stamped part number. Both were manufactured by the New Departure Hyatt (NDH) Division of GM. These have the embossed date stamp as you pictured. Date stamping of parts was a "habit" of GM parts manufacturing divisions, but many outside suppliers to GM did not date stamp parts.

However, the cap seen on many, if not all, 1981's is the all plastic, flat top, white cap. This cap is manufactured by Stant. I do believe that this cap was either a white plastic version of the 22525300 or, possibly, a predecessor part number to the 22525300. On the known-original cap from the 1981 I pictured, the only numeric embossment I can find is a "2-3" which I do not believe is a date code.

[Tom R.]

Re: 1981 Corvette Gas Cap

Joe

Terry might be interested in this but I have managed to collect I believe a range of the non-vented caps from 1975-82 and have outlined a powerpoint (tech session) on caps, date codes and "ears." Not sure who cares...but I got em.

Yes, the 22503147 is configured as I would expect. This goes to show that the caps specified in the AIM were not always the ones actually installed. For 1979 through 1981 the AIM's specify cap GM #559346. The P&A catalogs show the 559346 for 1979. However, the GM #22503147 is shown in the P&A for 1980 and 1981. Both the 559346 and 22503147 are very similar caps. Both have a convex steel cap with stamped part number. Both were manufactured by the New Departure Hyatt (NDH) Division of GM. These have the embossed date stamp as you pictured. Date stamping of parts was a "habit" of GM parts manufacturing divisions, but many outside suppliers to GM did not date stamp parts.

I have several caps of both part numbers and they are idential except the stamped number. In fact, I was using the GM# 22503147 (in the photo) on my Pace Car that, as you would expect, fit and functioned just fine.

However, the cap seen on many, if not all, 1981's is the all plastic, flat top, white cap. This cap is manufactured by Stant. I do believe that this cap was either a white plastic version of the 22525300 or, possibly, a predecessor part number to the 22525300. On the known-original cap from the 1981 I pictured, the only numeric embossment I can find is a "2-3" which I do not believe is a date code.

Vendors usually want a premium price for white caps like $50 at swap meets (i.e., Carlisle) so I have passed on many...the only one missing from my collection of non-vented gas caps for 1975-82 Corvettes...FWIW.

[Terry M.]

Re: 1981 Corvette Gas Cap

Tom,
That power point would be excellent material for the classroom part of the AJS as I get that feature rolling; but you would have to be the presenter because I haven't a clue.

[Tom R.]

Re: 1981 Corvette Gas Cap

Sure! I should also do a write-up for Vinnie. However, I have noticed that the "call for papers" is not as necessary as in the past...lots of submissions. I have to thank the many contributors on the tech board for the inspiration to do the research. It also gives me something to look for at Corvette swap meets.