1967 Corvette Oil Cap

[Timothy B.]

My 67 is a early September 66 build and I am not sure if this oil cap could be original or someone changed it at some time, the cap was on the car when I purchased it in 1984.

Has anyone with a early 67 ever seen a oil cap like this??

Thanks as always, Tim Barbieri

[Joe L.]

Re: 1967 Corvette Oil Cap

My 67 is a early September 66 build and I am not sure if this oil cap could be original or someone changed it at some time, the cap was on the car when I purchased it in 1984.

Has anyone with a early 67 ever seen a oil cap like this??

Thanks as always, Tim Barbieri

Tim-----


This is not the style cap that was used in "typical factory production" for a 1967 small block. In fact, I did not even realize that this style cap would fit on a 67 filler tube but, obviously, it does.

This is a GM cap, though. It's what's called an AC FC-2 and it was used on most 1969 and later small blocks (valve cover mounted filler). It was also used on many other Chevrolets and other GM cars of the period.

Is it possible that it was originally installed on your 1967? Yes, I'd say it's a POSSIBILITY, regardless of how slight. However, I don't think it would be accepted by a judge as original.

[Timothy B.]

Re: 1967 Corvette Oil Cap

Thanks for the reply, Joe. I have not looked to see if the cap is reproduced, would the correct cap still be available from GM by chance??

[Joe L.]

Re: 1967 Corvette Oil Cap

Thanks for the reply, Joe. I have not looked to see if the cap is reproduced, would the correct cap still be available from GM by chance??

Tim-----


The original cap, GM #3881834 for your 300 hp engine application, was GM-discontinued several years ago. However, an excellent reproduction is available.

[Timothy B.]

Re: 1967 Corvette Oil Cap

Thanks Joe, I will order one.

[Gerard F.]

Re: 1967 Corvette Oil Cap

Tim,

Here's my original on a late 67 327/300 for reference:





Pretty plain looking with the only markings being the S on the center rivet.

I did paint it once, looks like it is ready for another shot

[Peter L.]

Re: 1967 Corvette Oil Cap

Tim/Jerry - As always, Jerry has excellent examples and accompanying photos of the original parts from his car. This same cap configuration was also used on early '67s and is like the one on my early '67 (#1476). Please note configuration the roundness of the rivet head and the "S" stamping. Later versions of this part had a different configuration to the top of the rivet that is not rounded like Jerry's example. Jerry's example would be what I would expect on a '67 (and '66) base motor Corvette engine. Regarding the finish of the top of the cap, the 67 Corvette TIM&JG says the cap can be painted semi-gloss black or chromated with a dark greenish-black finish. If you find one with what the TIM&JG calls the "chromated" finish, they are exceptional and have a green and purple hue reflection when held at the right angle to light. Pete

[Scott S.]

Re: 1967 Corvette Oil Cap

Tim/Jerry - As always, Jerry has excellent examples and accompanying photos of the original parts from his car. This same cap configuration was also used on early '67s and is like the one on my early '67 (#1476). Please note configuration the roundness of the rivet head and the "S" stamping. Later versions of this part had a different configuration to the top of the rivet that is not rounded like Jerry's example. Jerry's example would be what I would expect on a '67 (and '66) base motor Corvette engine. Regarding the finish of the top of the cap, the 67 Corvette TIM&JG says the cap can be painted semi-gloss black or chromated with a dark greenish-black finish. If you find one with what the TIM&JG calls the "chromated" finish, they are exceptional and have a green and purple hue reflection when held at the right angle to light. Pete

Pete,

I found what looks to be one of the "chromated" caps, black-ish in color with hues of green visible when held at an angle to the light. The center rivet is at least one of the issues here. It has the "S" for Stant and it is round, but it is NOT smooth like Jerry's example above. It has four raised rounded-triangular surfaces, or conversely, the shape of an "X" has been cut into the top of the rivet surface, leaving the four rounded-triangular sections. The "S" appears to be the same as my L79 chrome oil-fill cap, with the top of the "S" being slightly smaller than the bottom half of the "S".

Is this a Corvette oil-fill cap, or a cap for some other model?

[Ronald L.]

Re: 1967 Corvette Oil Cap

What you are referring to as black green to purple chromate is in all reality black oxide.

Lots of threads on that here for the big block mid year oil caps, process and supplier Stant are the same.

Paint would not be an acceptable restoration.

I had a local BO shop redo my BB cap, only issue is that process completely eats the paper gasket. That - coaching a new paper gasket on the cap is something for later this year.

[Peter L.]

Re: 1967 Corvette Oil Cap

Scott - It is a functional p/n 3714893 '66-'68 base motor Corvette oil cap and also used on other Chev engines, but it is not the configuration I would expect originally on the '66-'68 Corvette base motor engine. The rivet configuration both top and bottom are typical of later production STANT oil filler caps and not typical of the caps used originally on base motor '67 Corvettes. As you noted the top of the rivet is markedly different from the that on Jerry's original example and in addition the configuration of the bottom of the rivet differs in the center "hole" with the originals having a bigger "hole." Pete

[Scott S.]

Pete, thank you for the explanation.

On a different but related subject, I have seen NOS chrome oil-fill caps sitting next to the GM packaging, implying the featured cap was in the GM packaging, but showing the base engine 3881834 part number on the GM paper envelope. If it only happened once, I would guess it was just an mistaken mix-up of packages and parts, but there are at least two different NOS examples on eBay right now, showing chrome oil filler caps with the base engine part number on the GM packaging

According to both the 1966 and 1967 AIMs, the base engine oil fill cap is # 3881834, while the engine oil fill cap (in UPC L79-A1, which should be the chrome cap) is # 3882864.

The AIMs don't specifically reference "chrome" for the oil fill cap under RPO L79, they just use a different part number than what is called out for the base engine oil fill cap. The parts books reference "chrome" for some other years (e.g. 1969-70 w/H/Per., Sp. H/Per. '350'... 3851735 ... CAP ASSY., chrome), but the books I have don't list the finish for 66-67 p/n 3882864.

Is my understanding correct that an NOS L79 chrome oil-fill cap should be part #3882864?

[Peter L.]

Re: 1967 Corvette Oil Cap

Scott - I also have an GM package with the base motor oil filler cap p/n that had the chrome plated oil filler cap. And yes, as far as I know the chrome one is the appropriate one for the 66-67 350 HP 327. I guess they failed to tell the folks that put the caps in the packages that one had the black finish and the other was was chrome plated. I bet that either one of them cost about the same to make in the old days, so it didn't make much difference which one ended up in the package at least for the base motor one. Although I'm sure if you owned a 350 HP engine and you wanted the chrome one and got the black one you might not be happy. Pete

[David L.]

Re: 1967 Corvette Oil Cap

While digging through my collection of oil caps I found this cap which appear to be a 66-67 Corvette 327 cap. The cap measures about 2.2" in diameter and measures about 2.5" from the end of one "ear" to the end of the other "ear". However, the recessed area around the rivet stamped "S" measures about 1.1" in diameter. The recessed area on the Jerry's original late 67 327/350 cap is just large enough to fit the "S" rivet, maybe 0.5" or 0.6" in diameter.
Could my cap shown below in the attached photo be an early version? It's not a reproduction as indicated by the pitting. I buffed off the dark gray coating and surface rust with my buffing wheel. It is not chrome plated, just buffed. Any comments or ideas?

Dave

[David L.]

Re: 1967 Corvette Oil Cap

Here is a photo of the back side of the cap. I cleaned off most of the rust but not all of it.
Dave