Radiator Caps (All)

[Thomas D.]

I sell reproduction radiator caps, and for the most part, I feel they are pretty close (if not exact) reproductions. Every year it seems the rules change and we make another version or configuration to meet judging standards. In many cases, I have never seen an original cap that NCRS manuals discribe, yet we will make it never the less.

My goal is simple...I want to do it right. The different versions are growing, and that can't be right. Who comes up with all these different configurations?
I would like to collect any original samples and/or photos of Corvette rad caps and/or any GM documents anyone might have to back up the history and usage.

This summer I saw someone paying $70 for a replated original cap that was so pitted I could hardly make out the letters. We need to stop this kind of madness and make the right thing. I just need to know what that is.

I'll be at Carlisle in a couple weeks, with my caps, and I'll bring a digital camera. Bring your caps over to compare! We'll take photo's of any original and make notes of anything different. Any help will be greatly appreciated and the hobby will be better for it.

[Patrick H.]

Re: Radiator Caps (All)

Tom,

Curent reproductions are not exact, unless the tooling has changed significantly in the last year.

The most obvious difference I see is the lettering. The reproduction caps have lettering that appears to almost be engraved, and the letters are quite thin with respect to heaviness of the font. Rub you finger across the lettering and you can feel the metal "heaped up" (exaggeration here) and rough.

Original caps have wider (i.e. thicker) fonts, and appear whacked in quite deeply. Someone took a BFHammer (or likely BF stamping machine) and whacked in the lettering. The cap is actually somewhat deformed due to the process. Repro caps are flat with that engraved (appearing) lettering.

The other differences are the size of the "ears" although recent reproductions are better. They used to be too small. In addition, the arrows of a reproduction were spaced incorrectly when comparing the distance of the letters, arrows and central depression.

Then again, you likely know this, but I thought I'd mention it for others. This general info is based on 63-7? caps; I don't do solid axle cars. I have pictures of MANY radiator caps, both original and reproduction, in case I ever get that article written for Terry...
If you're interested in doing a story together, let me know. I've got a lot of the background done.

Patrick

[Joe L.]

Re: Radiator Caps (All)

Tom-------

I applaud you and totally agree with you. I think that there are several factors which influence this thing on radiator caps. Among them are the following:

1) Radiator caps are a very "portable" sort of part. They can be changed with the greatest of ease. Sometimes, I think that folks think that because the cap on their car APPEARS old and is an AC piece, it "must" be the original cap. Who really knows, though, if the cap wasn't changed years earlier, maybe within the first few years of the car's life and for a variety of reasons? It's very hard to document or know for certain if a given radiator cap really is the one originally installed on the car. In some cases, I think that these "known original" caps have become the "standard" by which other caps are judged. This same "phenomenon" also affects judging of other components;

2) Some of the radiator caps used on Corvettes were the same as those used on passenger cars. The only real exceptions were the RC-20, RC-22, and RC-26 used on 1960-72 Corvettes with aluminum raditors and/or aluminum supply tanks. So, GM was producing a LOT of these non-Corvette-unique radiator caps. They may have been produced in different plants with slightly different tooling or, even, on many different machines within the same plant with different tooling. I feel that there may have been variations in the caps with respect to nuances of configuration even within a given model year for a given application. Even the Corvette-unique caps may have been produced on different tooling. Consequently, and this is an important point, the only way to know, for sure, what cap was originally installed on a particular Corvette is to have the KNOWN ORIGINAL cap that was installed on a particular Corvette. Very few people, except original owners who have exclusively serviced their own cars over the years, are in a positon to know if a particular cap is original to their car. Fortunately, I'm one of them. I have the known-original cap for my car (not still on the car). I can say, for certain, that it's the one originally installed on my car. But, no way can I say that every other 1969 RC-26 radiator cap was exactly the same;

3) From my observation, the type number stamping on these caps appears to have been a stamping that was done seperately from the rest of the stamping on the cap. So, even though some Corvette cap types are unique to Corvettes, they may have been produced on various assembly lines/plants along with other caps. The same differences described above that could affect the common caps, might affect the Corvette-only caps, too. In other words, there's no way of knowing that the Corvette-only caps were produced on a dedicated assembly line at only one plant. I believe that it's more likely than not that they were produced on a variety of assembly lines at, perhaps, a variety of plants;

4) adding more confusion to the whole issue, for some reason that I've never been able to determine, PRODUCTION radiator cap part numbers were different than SERVICE radiator cap part numbers. I don't know why this was the case since the caps were supplied as a single piece; it's not as if the part number on the box represented the part number for 2 or more pieces contained in the box. Whether there were differences between PRODUCTION and SERVICE caps, I don't know. It doesn't seem logical that there would be differences, but I've learned that GM "logic protocols" don't always follow common ones.

[Geoff C.]

[Joe L.]

Re: Corvette Cookie Cutter Sale

Geoffrey------

I still think that the elfs from der forest had something to do with these radiator cap repros. I see their hand in it all. When are those guys going to give it up?

[Geoff C.]

Re: Corvette Cookie Cutter Sale

Joe

Kenny Rubin made a repro. I think Richard Cohen did also. But the i's, the t's, the chisel, the depth, the shallowness, the nip, the bit, and the tip were all very, very different than those run on that single machine at now closed AC Delco factory in Phlint operated by old Sparky McPhart who made every single Corvette radiator cap. He told me so.

We're gonna have some more fun at Carlisle this year. Best arrangement ever in the same spot. And it's about time after 24 years. Remember, I have voting rights now in the Borough of Carlisle and will run for Justice of the Peace, so I can perform marriages as well as give away Corvette newsprint and good/bad avice.

Geoffrey Coenen

PS I actually think these repro caps look nice at the prices they pull and the power of the monocular I do not use for their examination. However the best examinations are those done with your finger(s) and your experiences may vary.

[Joe L.]

Re: Corvette Cookie Cutter Sale

Geoffrey------

I thought I saw you carrying around one of those "broach buster" scopes in your back pocket. But, the way things are, you gotta have one to protect yourself from these jerks that try to pass off a car with a stamp pad with "funny" broach marks.

In fact, I think that I saw you sneak that scope out and train it on the derrieres of some of the cute gals as they walked by last year. Now that I think about it, I'm not so sure that was a "broach buster" scope. It might have been one of those "x-ray vision" things that lets you see through clothes. What the heck, though, no sense in letting anything worthwhile get by if you've got the means to check it out.

[Thomas D.]

Re: Radiator Caps (All)

Joe,

You hit the nail on the head! How can anyone claim positively that they have an original cap unless they owned the car from day one and even then, are all the caps the same? I say no but as you know, judging doesn't allow for options. We must have clear discription of a part and application and in the real world that just didn't always happen.
Often the repro caps have been geeked on points because of the "thin" letters. It appears that the same tooling was used for many years and thousands of caps and that as the tooling became dull, the letters became wider.
With so many unknowns, I personally would never deduct points for a radiator cap as long as it fit the judging discription. (IE RC26 15#) Going any further is wrong and impossible to prove there wasn't variations.
But I am still going to try to make them better. If we can get them closer and maybe some of them "exact" I'll offer them with no specific years or usage and let customers decide what's right and what isn't.

[Loren L.]

KUDOS to the Doc for grabbing us by

the throat and dragging us, kicking and screaming, into the Real World. Now, we need to go one step further and consider the possibility - in the case of hose clamps - that Wittek was NOT the General's only supplier....

[Harmon C.]

Re: Radiator Caps (All)

One needs to keep in mind their are 4500 points and your judge takes off one point for your cap right or wrong because he is the expert on caps he may just miss something that is really wrong. If one tries for a 97 and is happy with it you will enjoy NCRS judging but if you need 99.9% you will come up short as the experts will get you right or wrong. If the caps you make are by the same method GM had them made they will pass most judges. I see one post that says etched not stamped and the font not TFP both will put a part in the area where the expert takes over. Lyle

[Patrick H.]

Re: Radiator Caps (All)

"I see one post that says etched not stamped and the font not TFP both will put a part in the area where the expert takes over."

Just my $0.02, but I don't think it takes any expert to see the difference between the lettering of an original and a repro cap when it comes to the font and the etching or stamping appearance.

I applaud Tom for wanting to improve the quality of his reproduction radiator caps.

Patrick

[Jack H.]

Is anyone duplicating....

the cup-shaped overflow mechanism? In addition to judges looking at font, placement of characters/pictorials, and the plating (brite vs. dull), every reproduction cap I've seen has a very different overflow mechanism on the bottom side vs. originals from the period (whether they be Corvette or pass car/truck)....

[Patrick H.]

Re: Is anyone duplicating....

I doubt it.

I would "guess" (and it's nothing more than that) that the current mechanism is the same on used in current day ACDelco caps. I could easily check this evening at home as I own originals, repros and current day caps. But, why reproduce what you can easily obtain?

In addition, in judging, the caps are not removed (for obvious reasons). Terry and I even discussed whether or not to include such info in an article, as we didn't think we wanted judges opening up hot cooling systems to check the accuracy of the cap underside.

I know that the restored caps (at least from one source) use current day innards riveted in place on an old cap.

Patrick

[Joe L.]

Re: Is anyone duplicating....

Jack------

This thing with "dull versus bright" plating has always confounded me. Many folks say that the current zinc or cadmium plating on parts (radiator caps or otherwise) is "too bright". However, how can anyone verify what the "brightness" was of the original plating? Zinc, cadmium, and most other metallic elements used for plating OXIDIZE when exposed to atmospheric oxygen (and, other oxidizing compounds that may be found in a polluted atmosphere) and they consequently "dull". One of the few exceptions to this is gold and one finds very little gold plating ever originally used on Corvettes. Although it's true that the oxidation proceeds more quickly and more extensively for parts that are actually used on a car, even those NOS pieces found in boxes suffer from oxidation and the inevitable "dulling" of the finish due to the build-up of the metallic oxide. So, unless someone has some original plated pieces that were produced in the 50's, 60's, and 70's that were IMMEDIATELY HERMETICALLY SEALED, I don't see how anyone can say what the "brightness" of the plated pieces was when they were new. Personally, I've acquired a lot of NOS pieces over the years but I've yet to come across one that was hermetically sealed.

[Tony H.]

Re: Is anyone duplicating....

I have an original, unrestored RC-26 cap and two original, restored RC-26 caps that have another difference I noticed that would not be obvious unless removed from the car. The springs used in the restored versions were coiled in the opposite direction (right-hand vs left-hand) than the known original (unrestored) cap. I would be in favor of including all the information that may be known for fact in an article, regardless whether it can be shown (judged) on the field or not. I started this collection to someday write an article for the Restorer. I'd be interested in collaborating.