RC-26 cap

[Kevin M.]

Can you tell a difference between a repro RC-26 expansion tank cap and an original one?

I seem to find an occasional origianl RC-15 cap, but have yet to find an original RC-26 anywhere... was wondering if it is because they are rare, or if a good quality repro has made them not so noteworthy...

Thanks!

[Patrick H.]

Re: RC-26 cap

Kevin,

The repro RC-26 is as bad as the repro RC-15, and contains essentially the same errors. Unfortunately the RC-26 was only used on Corvettes, so real ones are very rare. The RC-15 was used on millions of GM cars so is quite easy to find.

I hope that helps.

Patrick

[Wayne M.]

Here's one variant off my early '65 C60

Was on my car when purchased 27_1/2 years ago (and still is).

This may be only one variant of how they were stamped (Patrick will know the others). Note the stamp bounce 15#, RC-26

[Peter L.]

Re: Here's one variant off my early '65 C60

Wayne - Neat pre-1966 double stamp RC-26. The 1966 and later RC-26 had the AC logo in a circle and 15# and under that RC-26 on one of the ears.

I have no clue what/where the reproduction folks got the example they used for the reproduction cap!!!!!
Roswell perhaps.

Pete

[Patrick H.]

Re: Here's one variant off my early '65 C60

Pete,

You should easily be able to tell where they got their example to use in making the RC-26 caps.

Look at some of the oldest RC-15s in your collection, and compare them. The repro guys just used the same format all the way through, for each type of radiator cap. They didn't care how accurate they were once they got past 1961!
Of course, that's just in describing the style, not the myriad of other errors in the repro caps.

Patrick

[Gerard F.]

Re: Here's one variant off my early '65 C60

Pete,
Here's what I think is my original on a 67. The radiator guy says I should replace it, but it seems to work after all these years. It even pops off some pressure once in a while when the car gets hot.

Is that the correct orientation of 15# and RC-26 on the later models?

Jerry Fuccillo
#42179

[Patrick H.]

Re: Here's one variant off my early '65 C60

Looks great, Jerry.

Let me know if you ever want to sell.

Patrick

[Kent K.]

Re: RC-26 cap

Patrick,
See photo attached of my original 1969 435HP radiator cap with double strike 15# RC-26 turned sideways on the tab. Sorry about the condition, but I like to exercise caution cleaning things.
Regards, Kent

[Joe R.]

RC-26 cap, original/repro comparison

Hi Patrick:

Attached is a photo that compares my original 67 cap to a repro cap that I bought from LIC a couple years ago. In my opinion, the repro cap is pretty good, although I think that the earlier reproductions were not as well done.

If I were judging, I would be inclined to give full credit for this repro cap. While I can see certain differences in this particular comparison (such as the rivet), they seem small enough that they might be typical of normal production variation.

One way to distinguish the repro cap from the original is to look at the underside, where the repro spring is wound in the opposite direction of the original, and the spring metal behind the seal is a different material. However, as I understand it, judges are now being discouraged from removing the caps to inspect the undersides.

[Joe R.]

Re: Here's one variant off my early '65 C60

Hi Jerry:

I have been told that the orientation of the 15# and RC-26 appeared both ways on original caps. Check the photo that I posted of my original 67 cap (April car), which has a different orientation from yours.

[Patrick H.]

Re: RC-26 cap, original/repro comparison

Joe,

There are actually a couple of vendors of the repro caps. LICS has them made for themselves, and does not buy them from elsewhere. Most vendors buy them from a different source than LICS, and I'm not sure if LICS sells them to any other catalog house.

His are the closest RC-26s to an original, but I can see several small differences between them. Then again, I've spent a LOT of time comparing radiator caps. I doubt that most judges would do that for a point.

Patrick

[Rick S.]

Re: Here's one variant off my early '65 C60

Patrick and others,
I was a newbie at the time and bought a new expansion tank and cap a few years back from Dewitt's Radiator without checking the JM and got dinged at judging. What Dewitt's sold me and they still list on their website is a 13#307 on the right ear within a circle. Does anyone know why Tom sells an incorrect cap that is in direct conflict with the JM? This is for a small block, non AC. http://www.dewitts.com/pages/product....asp?ProdID=84

Also Joe Randolph does Long Island still sell the reproduction cap you posted in your photo?
Regards,
Rick

[Joe L.]

Re: Here's one variant off my early '65 C60

Joe, et al-----

This is a big problem when folks try to determine if a reproduction piece is original by comparing it to a known original. That comparison assumes that ALL original pieces were exactly like the original piece in hand. That's not always the case, and it's especially not always the case for an item like a radiator cap. AC was manufacturing these caps by the "bazillions" in the 60's and 70's. It's true that the "307" or RC-26 were Corvette-only pieces and were undoubtedly manufactured in smaller numbers. However, the shell was most likely stamped off the same tooling as was used for most other caps. So, it may very well vary depending upon the particular tooling set that was used to manufacture it.

Basically, I think that the only part of the cap that received a "custom stamping" was the model number and relief pressure. The rest was "standard".

[Joe R.]

Re: Here's one variant off my early '65 C60

Hi Rick:

You asked if LIC still sells a repro cap like the one I showed in my photo. I don't know the answer, but I suspect that what they are selling today is similar to the one I bought from them a couple years ago.

[Gerard F.]

Looks like this one is more correct

Rick,

for a non-AC 67.

http://www.dewitts.com/pages/productdetail.asp?ProdID=86

Shown for a 64-72 S/B AC car. Looks like mine, only the marking is further to the center. Mine is a non-AC 67.

Now you guys have got me wondering if I have the right cap, even though I'm pretty sure it has been on the car for some 40 years.

Jerry Fuccillo
#42179