Another RC-15 question

[Dave Morris]

Hi everyone.
Recent posts about the RC-15 radiator caps have made me look at a couple I have. Can someone tell what the "H" or "G" or other letters refer to when talking about these caps. I can see no other letters on the caps I have and am wondering what I am missing. Also, I have one with 1 circle around the AC and another with 2 circles. The plating seems a slightly different color too. Can anyone straighten me out or point me in the direction or where to look.
Thanks,
Dave #1684

[Tony H.]

Re: Another RC-15 question

Dave,

Patrick and I are doing some research on radiator caps used in Corvettes for the bumper years (pre-73).

In doing some of our research, we came across the letter designations on the RC-15 caps. My first recollection of these letters come from a repro manufacturer. The three letters that were used are D, F, & H. There is no particular meaning to the letters except that each is for a design change.

Typically, the D cap is the earliest RC-15 and was not used in Corvette applications. This cap had only the AC encircled and consisted of a brass hollow rivet. The F version of the cap was used in 1966 Corvette to 1967 on brass tanks. This version had two circles, one around the AC and another around the 15# RC15; this version used the hollow rivet. The H version was used in 68-72 Corvettes with brass tank applications and also consisted of two circles as the F version; the rivet is a flat brass rivet with a circular ridge along the rivet's top.

I don't know the story around A, B, C, E, & G. Perhaps they are versions that never made it to production or maybe they are FORD versions.

The cover of these caps we believe are zinc-plated steel. The appearance may vary from cap to cap due to age, environment, coating thickness, and plating processes, etc. It can vary from dull gray to almost a shiny chrome plating. Sometimes, it may be confused with cadmium plating and some restorers have replated these in cadmium. The cadmium plating, like zinc, can vary also for the same reasons.

Patrick and I are working on (finalizing) a Restorer article to help explain all of this. Pretty soon, we will have divulged all our knowledge on this discussion board. New information keeps floating in. We promise to get something out soon.

[Tony H.]

Re: Another RC-15 question

Dave,

Patrick Hulst and I are doing the article for the Restorer on this. I failed to mention his last name in the above post. Also, if possible, I would like to see pictures of the caps you have. In addition to top (cover) views, I would also like bottom and side views of the caps. Email would be fine. Thanks very much.

Tony

[Patrick H.]

Re: Another RC-15 question

Dave and Tony,

Yes, those letter designations are from one repro supplier only. Since I have a couple of the GM drawings for rad caps, I can assure you that GM never used these designations. It would have made my job easier if they had, but they did not.

Letter designations are for Chrysler 300 cars Tony, not f*rd products.

I'm hoping that the article is 95% done and sent out for review in the next week.

Patrick

[Art A.]

Re: Another RC-15 question

Patrick, if you need the drawings that you requested for the article by next week------it's not going to happen that soon. I probably won't have them until after Carlisle.

Art

[Patrick H.]

Re: Another RC-15 question

I e-mailed you, Art.

Patrick

[Pete NCRS # 30998]

Re: Another RC-15 question

Ok, by all this I should be looking for this cap for my 67/427 no air>The F version of the cap was used in 1966 Corvette to 1967 on brass tanks. This version had two circles, one around the AC and another around the 15# RC15; this version used the hollow rivet

hollow rivet, Correct?

Thanks,
Pete

[Patrick H.]

Re: Another RC-15 question

Correct. Hollow rivet.

Just make sure you get the correct hollow rivet configuration. "Most" of the RC-15s that are original have a correct rivet, but I have a service cap with a "slightly" different shaped hollow (dished) rivet. See my post above for the correct shape under the "1968" thread.

Patrick

[Pete NCRS # 30998]

Re: Another RC-15 question

Here is a pic of the cap that is on my vette currently>

Also here is a pic of the bottom and a close up of the hollow rivet>



Since this is not the correct cap for my 67/427 no ac vette, what car is it correct for. I polished it up with Flitz to take the pic, it was dull.

Thanks,
Pete

[Patrick H.]

Re: Another RC-15 question

Pete,

That is what I currently believe to be the "first" design of the RC-15. It was used in Chevrolet passenger cars from 1963 through 1965. I'd bet that 75% of the judges wouldn't know it's not correct for your car. Well, at least until the article when they'll all have no excuse.

You REALLY polished that, didn't you?

Patrick

[Pete NCRS # 30998]

Re: Another RC-15 question

I did shine it up. Should I sell it and look for the correct one?

[Patrick H.]

Re: Another RC-15 question

You could, but since this design was not used on big blocks, the demand is not as high as later ones. I'd keep it for now, use it for judging, and look for a correct one.

Patrick