Topic: 1967 unique distributor ported vacuum switch C7OZ-12A091-A

[67gta289]

Here are some additional pictures of the C7OZ-12A091-A discussed in the (locked) thread linked below

http://www.concoursmustang.com/forum/index.php?topic=19661.15

The plating is starting to fail in a few places.  Of course the plating on the service part might be different than the factory installed parts.

[Deuce]

Thank you for the excellent photos and measurements!  Probably as close as many of us will get to a NOS piece.

[J_Speegle]

Thanks for the posting and pictures. Yes believe that some of the original finishes have failed over the years on this piece or that it may have been plated differently from assembly line pieces as we have found on other parts when we compare original to service parts.

Thanks again

[67gtasanjose]

The plating is starting to fail in a few places.  Of course the plating on the service part might be different than the factory installed parts.

The plating type is the same as a July '67 dated one on my engine.
FWIW, My whole engine is dated in June/July 67, all castings and date stamps pretty close to one another with a final assembly date of engine in July '67. (I believe my ported vacuum switch to be an assemblyline item, correct for a July build example. It is a complete replacement engine assembly purchased with all components including this item. One of those "Wish I hadn't have done THAT" things now that I am restoring it...I bought the engine because it had much lower mileage. I installed it circa 1985/6)

[67gtasanjose]

Similar Ported Vacuum Switch just relisted on "The Bay" right now "On Sale" this time (not me). Listed as a C7AZ-12A091-C for Big Block Fords.

NOTE: Has the same Finishes as John's recent find. I believe this example & John's NOS example above, represent the original "finishes" we may expect to have seen on the Assemblyline back in the day. My ORIGINAL (7-67 dated) one was plated like these two within this thread, leading me to believe along these lines.

[J_Speegle]

Similar Ported Vacuum Switch just relisted on "The Bay" right now "On Sale" this time (not me). Listed as a C7AZ-12A091-C for Big Block Fords.

NOTE: Has the same Finishes as John's recent find. I believe this example & John's NOS example above, represent the original "finishes" we may expect to have seen on the Assemblyline back in the day. My ORIGINAL (7-67 dated) one was plated like these two within this thread, leading me to believe along these lines.

Thanks for posting. In this set of pictures the two different plating finishes is easier to see and along the lines I was expecting to see 

Tough pieces to find if you need them.

[Bob Gaines]

Similar Ported Vacuum Switch just relisted on "The Bay" right now "On Sale" this time (not me). Listed as a C7AZ-12A091-C for Big Block Fords.

NOTE: Has the same Finishes as John's recent find. I believe this example & John's NOS example above, represent the original "finishes" we may expect to have seen on the Assemblyline back in the day. My ORIGINAL (7-67 dated) one was plated like these two within this thread, leading me to believe along these lines.

I respectfully disagree. The valve end of the "John's recent find" has had the protective gold chromate coating removed by corrosion (white dicast oxidation) compared to the newest picture posted which has the chromate coating still intact (ported dicast valve end)  . This is the same coating applied to some carburetors most commonly seen on vintage Holley carbs.

[67gtasanjose]

Similar Ported Vacuum Switch just relisted on "The Bay" right now "On Sale" this time (not me). Listed as a C7AZ-12A091-C for Big Block Fords.

NOTE: Has the same Finishes as John's recent find. I believe this example & John's NOS example above, represent the original "finishes" we may expect to have seen on the Assemblyline back in the day. My ORIGINAL (7-67 dated) one was plated like these two within this thread, leading me to believe along these lines.

I respectfully disagree. The valve end of the "John's recent find" has had the protective gold chromate coating removed by corrosion (white dicast oxidation) compared to the newest picture posted which has the chromate coating still intact (ported dicast valve end)  . This is the same coating applied to some carburetors most commonly seen on vintage Holley carbs.

Bob, thanks for the clarification.

My intention was to clarify that I believed John's recent find initially BEGAN it's life looking more like the C7AZ-C example I found and recently posted images of. I also have some pictures of another C7AZ-C example (pictures available upon request) that not only is shaped differently than the one I just posted, it has an overall appearance of the whole ported vacuum switch being "gold" in color, thus NOT having the distinctive zinc-plated lower section. I am under the belief the "all gold" one I have pictures of, is a later Service Replacement. Since I had not mentioned anything about that "OTHER" (all-gold) finish I knew about, you would not have known what I was reffering to when I called the zinc-plated ones as "the same". I hope this statement is a better description of what I was trying to say when I compared John's find to the pictures I had just posted as "the same" as John's.

As always, the 'written words' often fail to communicate the thoughts. Bottom line, my previous post shows what we are seeking to duplicate. John's example "needs work" to get to the Concours-correct plating, I was under the impression that was obvious. I also wished to point out the "gold chromate" finish of an original ported switch portion of the assembly.

So, now the MOST IMPORTANT part of this discussion. A recent request a few weeks ago, asking what "finish we should find on the ported switch", http://www.concoursmustang.com/forum/index.php?topic=19602.0
it is my understanding that we should:

a.) begin with Restoring the finish to a gold chromate vacuum switch (upper section) crimped into a zinc-plated lower section/fitting/elbow.
b.) after being installed into the engine (using minimal shellac sealer), a restorer would
c.) loosely mask the upper gold chromate section & hose nipples (of both the vacuum hoses and the heater hose) and then the restorer would
d.) spray some engine color onto the areas of the ported switch/heater elbow that were not masked off, focusing the spray towards only the lower-most areas of the installed ported vacuum switch.

Is this "correct" or "close" to what we should be seeking to accomplish? (further discussion appreciated).

[preaction]

John, thanks for posting your find as it got me to thinking about when  and if a ported vacuum switch would have  been used with a 67 thermactor, A/C, automatic, equipted 390 Mustang/Cougar as it turns out it is not used in these applications as I discovered from research done here so that left me with when these were used my guess was that it found its way to the largest cars I found this application chart in a July/August shop tips booklet.

[196667Bob]

There must have been a change in thinking between July-August of 1967 and June of 1968. Attached is a copy from the 1960-68 MPC, dated June of 1968, which shows use of a ported vacuum switch on 1967, 390 Mustangs (although a different Part Number than the one posted for 289's), as well as yet another Part Number for all 1968 engines. This possibly could have occurred as one of the many "Changes" that occurred in 1967, or by a TSB (I haven't had time to check either yet).

Bob

[67gtasanjose]

There must have been a change in thinking between July-August of 1967 and June of 1968. Attached is a copy from the 1960-68 MPC, dated June of 1968, which shows use of a ported vacuum switch on 1967, 390 Mustangs (although a different Part Number than the one posted for 289's), as well as yet another Part Number for all 1968 engines. This possibly could have occurred as one of the many "Changes" that occurred in 1967, or by a TSB (I haven't had time to check either yet).

Bob

Regarding 67 Mustang 390 applications, I interpret your MPC chart to state the PVS was used on 2BC (2-barrel) cars. Only in 68 was there a 2BC 390 (X-code) and everything in 68 was different than anything in 67 for emission control parts so let's not go down that rabbit hole.

[J_Speegle]

So, now the MOST IMPORTANT part of this discussion. A recent request a few weeks ago, asking what "finish we should find on the ported switch", http://www.concoursmustang.com/forum/index.php?topic=19602.0
it is my understanding that we should:

a.) begin with Restoring the finish to a gold chromate vacuum switch (upper section) crimped into a zinc-plated lower section/fitting/elbow.
b.) after being installed into the engine (using minimal shellac sealer), a restorer would
c.) loosely mask the upper gold chromate section & hose nipples (of both the vacuum hoses and the heater hose) and then the restorer would
d.) spray some engine color onto the areas of the ported switch/heater elbow that were not masked off, focusing the spray towards only the lower-most areas of the installed ported vacuum switch.

Is this "correct" or "close" to what we should be seeking to accomplish? (further discussion appreciated).

Yes I believe that would lead a current restorer to reproduce what we currently understand. I still hold out the possibility of the base section originally having the dichromate dye coating over the zinc but will wait and watch for new examples to show up if they do in the future

[67gtasanjose]

Yes I believe that would lead a current restorer to reproduce what we currently understand. I still hold out the possibility of the base section originally having the dichromate dye coating over the zinc but will wait and watch for new examples to show up if they do in the future

Would you like images of the one I removed from my engine last week? It is zinc plated, no signs of dichromate in any of the areas protected by paint. It had been repainted but the zinc areas that were protected are silver in color, not gold.

[196667Bob]

Regarding 67 Mustang 390 applications, I interpret your MPC chart to state the PVS was used on 2BC (2-barrel) cars. Only in 68 was there a 2BC 390 (X-code) and everything in 68 was different than anything in 67 for emission control parts so let's not go down that rabbit hole.

Richard : The chart from the MPC only shows a 390 2BC for Thunderbirds (which is incorrect), and for Fairlanes (which is correct - Code Y). It does not show any other Models with a 390 2BC.
Also, it shows the 68's as a completely different Part Number, which as you noted, we don't want to get into here.

Bob

[Bob Gaines]

Would you like images of the one I removed from my engine last week? It is zinc plated, no signs of dichromate in any of the areas protected by paint. It had been repainted but the zinc areas that were protected are silver in color, not gold.

The only portion that is typically the gold chromate is the dicast vacuum tree portion and not the lower fitting portion. The NOS one from the ebay auction shows this difference. FYI the 68.69.70 and later vacuum trees are also the gold chromate which would indicate a pattern. This same gold chromate process has been used to protect diecast carb parts (same material as vacuum tree)since the early 60's .