Author Topic: 68 396 radiator cap  (Read 9529 times)

My68SS

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68 396 radiator cap
« on: April 29, 2006, 04:37:35 PM »
Hi, was the original radiator cap for 68 396 350hp the short eared or long eared type?
Were they 15 psi?
Any pics appreciated
Rob
1968 12C SS
L34/M40
12 bolt posi 3.55

lakeholme

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JohnZ

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Re: 68 396 radiator cap
« Reply #2 on: May 03, 2006, 03:19:19 PM »
Hi, was the original radiator cap for 68 396 350hp the short eared or long eared type?
Were they 15 psi?
Any pics appreciated

The caps with the short ears are later GM service replacements.
'69 Z/28
Fathom Green
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Pacecarjeff

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Re: 68 396 radiator cap
« Reply #3 on: May 05, 2006, 07:17:03 PM »
The repro caps are kinda close, but not exact at all.

A blind man could tell the difference.....
Actually, it might be easier for the blind guy to tell. ;D
The depth and style of the printing is the give away.

Big ears till the early/mid 70's

My68SS

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Re: 68 396 radiator cap
« Reply #4 on: May 05, 2006, 10:06:16 PM »
Quote
The depth and style of the printing is the give away.

Yup, have seen that issue on other bits  :)
Thanks for the replies
Rob
1968 12C SS
L34/M40
12 bolt posi 3.55

JohnZ

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Re: 68 396 radiator cap
« Reply #5 on: May 06, 2006, 02:50:47 PM »
There were MANY different configurations of the RC-15 cap in production and service, and there are at least four different reproductions on the market; there's an excellent research article on the history of the RC-15 cap in the Winter, 2006 issue of the NCRS "Corvette Restorer" magazine.  :)
'69 Z/28
Fathom Green
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MyRed67

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Re: 68 396 radiator cap
« Reply #6 on: December 15, 2010, 07:02:58 AM »
  Can someone post a pic. of a correct RC 15 Radiator cap?  As stated earlier on this post I am seeing many different versions.  I'm assuming a correct cap should #1 be stainless, and #2 have Big ears.  Should it have raised letters"NEVER OPEN HOT" or recess stamped letters "TURN TIGHT" and "REMOVE SLOWLY"?   I am even seeing caps claiming to be NOS both ways.  What is correct?
1967 Camaro  LOS  11A
Original Engine   Z - Tribute
Mike C.    NW - Illinois

My68SS

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Re: 68 396 radiator cap
« Reply #7 on: December 15, 2010, 02:17:00 PM »
Can't say that this is one I have is 'correct', but should be somewhere near the mark.
It's been re-plated and may be much brighter than original. Here in Au, AC caps fitted to GMH cars from the same era were steel with more of a gray galvanized finish.
Not sure that any caps from any manufacturer were stainless in those days.

John, was there one cap that was more common than the others?

Rob
1968 12C SS
L34/M40
12 bolt posi 3.55

JohnZ

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Re: 68 396 radiator cap
« Reply #8 on: December 15, 2010, 06:31:45 PM »
<<John, was there one cap that was more common than the others?>>

Not really - AC made thousands of them every day with multiple sets of tooling, and there were minor variations; all were zinc-plated with long ears, and there were several variations of the center rivet style. Any cap that's stainless or has short ears or says "never open hot" is a much later service replacement. Photo below is the original RC-15 on my '69 Z/28.
'69 Z/28
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My68SS

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Re: 68 396 radiator cap
« Reply #9 on: December 16, 2010, 10:55:50 AM »
Yes, I meant zinc plated, not galvanized.
John, yours looks to be more heavily stamped, giving and almost embossed look to the text and the circle around the AC and RC-15 being slightly depressed below the surface of the surrounding metal, which is exactly how I remember them from those days.

While we're on the subject, below is a couple of before and after cleaning pics of my '86 VL Commodore cap [GMH built car].
They weren't using AC caps by then, they were all built by another local company - CPC.
 
I cleaned it with CLR bathroom tile cleaner which is a weak organic acid [I think], spraying a bit on, then gentle scrubbing with a soft toothbrush then rinse off.
It only took about 20 secs for each side. I moved as quickly as I could so the acid had little to no chance of attacking the zinc.

I then phoned CPC to see if they could rebuild it for me, as all the rubber bits were shot.
To my shock and surprise, instead of the expected loud laughing ["You want us to do what!!... :D] I was put through to a guy who said "Sure, no probs, send it over and I'll do it for you"
After I got up off the floor, I asked him how much. He said he'd do it for free!!   :o

The last couple of pics are how it looked after coming back from CPC.

Rob
1968 12C SS
L34/M40
12 bolt posi 3.55