7 fin alum. valve covers
I have a question about the casting marks in the midyear Aluminum valve covers.I know that the mold cracked about march of 1966, and all covers after that have a very pronounced mark through the "0" in corvette.What I would like to know is, did the mold start to develop the crack gradually or break all at once? The reason I'm asking is, I have been looking for a set for my 65 365 and have seen the casting mark on almost all of the cars I have looked at even though they are supposed to be all original.Some of the cars have one side with no visable flaw while the other side is very subtle and diminished.Did the mold have any visable flaws in the 63,64,and 65 castings before total failure? Would any of the slightly visable casting flaw covers be correct for 65?Does the term casting flaw mean the very pronounced can't miss seeing seam through the "0" in corvette?
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Re: 7 fin alum. valve covers
Doug, Here is what I have observed. The crank/seam showed up first on the inside of the valve cover. Gradually it appeared on the outside in the letter "O" area.
The latest ones that Chevy sold over the counter had a very pronounced seam. So the mold gradually developed a flaw or crack.
It would not be typical for one to see a seamed valve cover on the' 63 to '65's and also the early '66's. Therefore it would not be correct for your '65 to have any type of casting flaw.
In searching for a valve cover or a pair of them please remember that the fellows who refinish these valve covers cannot make miss piggy look show quality.
If you see a valve cover loaded with white powder and it has some pitting then keep on looking.
How about a pic of your seamed valve cover. A close up of the seam. Thanks, John -
Re: 7 fin alum. valve covers
Doug,
The flaw did become worse over time. My January '67 valve covers both have the casting flaw, but it is very light, I don't think most people would notice it if they weren't looking for it. I have an old NOS example (1970s, I think) and the casting flaw line is very distinct, but the line is not wide or deep, and the "O" in Corvette is not filled in at all, unlike many of the later service replacement valve covers.
Other members here should be able to give more detail (and correct me if I'm wrong), but I suspect the crack happened all at once and then grew worse with usage, which would mean no flaw at all right up until the very last valve cover before the mold was cracked. It has been my understanding that Corvettes with one of each (one valve cover with the flaw, one without) is not uncommon for mid to late 1966 due to mixing of inventory, but by 1967 I think the flaw should be evident in all L79 valve covers if you look closely for it.Comment
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Re: 7 fin alum. valve covers
Does anyone know anything about this mold? How many valve covers did it make at once? Did the entire mold crack? Was it repaired?Comment
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Re: 7 fin alum. valve covers
I believe Paragon now owns the mold, possibly from Paragon can elaborate on the tooling.Comment
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Re: 7 fin alum. valve covers
Do a search in the archives, I believe this has been discussed extensively in the past as to the progression of the problem. Bottom line, the "O" was never filled in any of the original production pieces, Also watch for parts with the "O" simulated" by removel of the filled-in area, usually easily detected as a "configuration" issue in the scriptBill Clupper #618Comment
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Re: 7 fin alum. valve covers
Scott,
When I acquired my four-owner July build date '66 L79 it had one valve cover with the seam flaw and one without. I wound up finding two matched covers both with thin seams, typical of the early flaw, and having them nicely restored by John DeGregory. I did this in part so that I wouldn't ever have to "use up" any special pleadings to the judges about having a non-flawed cover after the accepted cut-off date given in the JG. I talked with several mechanical judges who said they don't ascribe to the possibility that unflawed covers would still be available on the assembly by late July of '66 . I figured I'd reserve my pleadings for some other aspect of my car that is not so easily fixed to comply with the JG. I know this goes against the philosophy of not wanting to change an original item to match the JG, but that's what I did in this case. You have to pick your battles.
GaryComment
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Re: 7 fin alum. valve covers
HI Gary, You are not the first car owner who has had mismatched valve covers from Flint. I have come up against this issue a hand full of times over the years.
But I do agree with your approach to it.
I don't quite understand Cluppers remark about the "O filled in.
Maybe because of the lack of sleep but is Bill saying that no assembly line cars had VC's with the "O" filled in? This I can understand as I have never seen a set of beat up originals with the slag in the "O" but have seen lots of NOS ones filled in.
Bill what do you mean on the next part of your comment. Are you saying you can tell if the "O" has been carved out??? Thanks, JohnComment
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Re: 7 fin alum. valve covers
Yes, I' seen plenty with the "O" filled in, but always on an over-the counter set, not production line installed, and yes, I've seen the "O" with an attempt at "cleaning out" the flaw, but not done properly as compared to an original.Bill Clupper #618Comment
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