1972 Closed Air Filter Element Technical Description Clarification

[Scott K.]

In reviewing the TIM & JG for 70 72 Corvettes, page 58, Section 4. AIR CLEANER, paragraph 3 discusses AIR FILTER ELEMENT.Starting with sentence 3, the description reads:

"An expanded screen filter has been seen on a few low mileage 1970 to 1972 Corvettes. The wording Best way to protect your engine.... indicates these as original. The gauge of the screen is smaller than current production. We have seen enough original filters and photos of engine compartments of new cars to conclude the correct original 1970-1972 air filter used an expanded metal outer screen. It had a vertical pattern, where the long dimension of each opening in the screen is in the vertical axis. The current AC filter with expanded metal outer screen has thicker metal and the lack of admonition, hot-foil stamped on the original filters, reading: BEST WAY TO PROTECT YOUR ENGINE -REPLACE WITH TYPE A 212 CW or A 329 CW."

In reading this description above, the first three sentences infer that since "Best Way" was present on a few low mileage 70 to 72 Corvettes and through lack of further description it should therefore be the standard for ALL air filter elements of this period? There are no details or descriptions herein regarding Open vs Closed air filter elements and their differences nor is there distinction between the design, markings or stampings of the 212 vs 329 filters.

Further, there seems to be a middle ground (ie: missing statement that closed the gap between the "few" and "current") where the description of the "few" ends after sentence 5 and the 6th begins with "The current AC..".

In reading many of the posts on this subject at this site, there are descriptions of what originals are believed to look like / read -vs- service replacements. There also seems to be debate about the extended use of "best of" during this period.

Should the description of Air Filter elements be revisited and expanded to provide additional clarity?

Questions I have:

1. Do ALL (both 212 and 329) filter elements ABSOLUTELY state "Best way".. OR are there some that exclude these words and begin with "Protect"?

2. Is there a difference in the wording/stampings on A329C -vs- A329CW air filter elements? (with the W referring to wetted) And then how about the mesh?

3. Seems they are all supposed to be yellowish in color (implying wetting).. but is the mesh different in open vs closed systems?

[Terry M.]

Re: 1972 Closed Air Filter Element Technical Description Clarification

In reviewing the TIM & JG for 70 72 Corvettes, page 58, Section 4. AIR CLEANER, paragraph 3 discusses AIR FILTER ELEMENT.Starting with sentence 3, the description reads:

"An expanded screen filter has been seen on a few low mileage 1970 to 1972 Corvettes. The wording Best way to protect your engine.... indicates these as original. The gauge of the screen is smaller than current production. We have seen enough original filters and photos of engine compartments of new cars to conclude the correct original 1970-1972 air filter used an expanded metal outer screen. It had a vertical pattern, where the long dimension of each opening in the screen is in the vertical axis. The current AC filter with expanded metal outer screen has thicker metal and the lack of admonition, hot-foil stamped on the original filters, reading: BEST WAY TO PROTECT YOUR ENGINE -REPLACE WITH TYPE A 212 CW or A 329 CW."

In reading this description above, the first three sentences infer that since "Best Way" was present on a few low mileage 70 to 72 Corvettes and through lack of further description it should therefore be the standard for ALL air filter elements of this period? There are no details or descriptions herein regarding Open vs Closed air filter elements and their differences nor is there distinction between the design, markings or stampings of the 212 vs 329 filters.

Further, there seems to be a middle ground (ie: missing statement that closed the gap between the "few" and "current") where the description of the "few" ends after sentence 5 and the 6th begins with "The current AC..".

In reading many of the posts on this subject at this site, there are descriptions of what originals are believed to look like / read -vs- service replacements. There also seems to be debate about the extended use of "best of" during this period.

Should the description of Air Filter elements be revisited and expanded to provide additional clarity?

Questions I have:

1. Do ALL (both 212 and 329) filter elements ABSOLUTELY state "Best way".. OR are there some that exclude these words and begin with "Protect"?

2. Is there a difference in the wording/stampings on A329C -vs- A329CW air filter elements? (with the W referring to wetted) And then how about the mesh?

3. Seems they are all supposed to be yellowish in color (implying wetting).. but is the mesh different in open vs closed systems?

Scott, if you are quoting from Edition four of the 1970-72 TIM&JG it would be important to know that that edition was last revised in 2006 or earlier. I think the 2006 date is right, but I could be wrong about that date. My point is that the information in that edition is at least six years old. The material contained in that edition is what we knew at that time. Your reading of this board may include information generated since that edition was published.

However, and most importantly, almost all of the information posted on this board is relevant to SERVICE replacement filters. NO ONE has produced a verifiable factory installed 1970-72 Corvette air filter since or before 2006. What you refer to as a gap in the information in the fourth edition TIM&JG is exactly there because we did not wish to include SERVICE information when we had a suspicion that there was a difference between factory installed and service filters. That suspicion still exists, and it would be a disservice to authenticity (although not to some vendors and filter collectors) to include SERVICE data unless and until PRODUCTION data can be established.

"Should the description of Air Filter elements be revisited and expanded to provide additional clarity?" Maybe a statement as above, perhaps edited for focus, could be added to the next edition, you will have to take that up with the National Team Leader. At this time there is no revision of the 1970-72 TIM&JG scheduled -- so whatever happens will not happen too soon.

[Scott K.]

Re: 1972 Closed Air Filter Element Technical Description Clarification

Terry,

Appreciate the response. You are correct sir! Was reviewing the Fourth Edition when it became apparent that Judging may be based on limited or out of date information given the confirmed age of the TIM & JG for 70-72 vehicles.

So, I'm still pretty much where I started which is that the TIM & JG establishes an baseline based on a few examples (out of thousands of vehicles manufactured) and then fast forwards to current day reference, leaving field interpretation as to what may or may not be acceptable in between. I find the TIM & JG valuable.. but often inconclusive and lacking updates as you've identified. Probably time that updates get added to these guides? I'd be happy to pay a fee to purchase an update.

Net/net: Trying to do a reasonable job in restoring my 72 and sorting fact from fiction is a interesting proposition for certain.

Thanks again for the insights.

Scott.

[Terry M.]

Re: 1972 Closed Air Filter Element Technical Description Clarification

Terry,

Appreciate the response. You are correct sir! Was reviewing the Fourth Edition when it became apparent that Judging may be based on limited or out of date information given the confirmed age of the TIM & JG for 70-72 vehicles.

So, I'm still pretty much where I started which is that the TIM & JG establishes an baseline based on a few examples (out of thousands of vehicles manufactured) and then fast forwards to current day reference, leaving field interpretation as to what may or may not be acceptable in between. I find the TIM & JG valuable.. but often inconclusive and lacking updates as you've identified. Probably time that updates get added to these guides? I'd be happy to pay a fee to purchase an update.

Net/net: Trying to do a reasonable job in restoring my 72 and sorting fact from fiction is a interesting proposition for certain.

Thanks again for the insights.

Scott.

Having been through several revisions of both the 1968-69 and 1970-72 manuals I can tell you that the timing of revisions are not based on cost to the end user. EVERY ONE has been long overdue when it was finally complete, and every one needed revisions of those revisions before the changes reached print. Every one also contained mistakes and omissions. They are all done by volunteers who on occasion find that other matters take precedence in their lives.

Most of the observations in these manuals are from relatively few examples. The Internet has made it easier to expand those examples, but in the bigger scheme of things our observations will always be drawn from only a small percentage of the cars built. If we waited for significant numbers to be observed it would be a long time before any manual was produced. I expect many of us, even the youngest, wouldn't be alive for the first manual if significant numbers were the criteria.

Your original point is well taken and that paragraph on air filters could stand to be clarified. If we can find our way through the mass of data on SERVICE filters we should do that, and include a statement about PRODUCTION v SERVICE filters.

[Scott K.]

Re: 1972 Closed Air Filter Element Technical Description Clarification

Good points.. however statistical relevance would lend improved validity.

[Terry M.]

Re: 1972 Closed Air Filter Element Technical Description Clarification

Good points.. however statistical relevance would lend improved validity.

I agree. I guess I will have to say I agree a second time to satisfy the dumb computer.

[Scott K.]

Re: 1972 Closed Air Filter Element Technical Description Clarification

I guess I will have to say I agree a second time to satisfy the dumb computer.

.???? What?

[Rick M.]

Re: 1972 Closed Air Filter Element Technical Description Clarification

Couldn't updates be posted on this site?

[Scott K.]

Re: 1972 Closed Air Filter Element Technical Description Clarification

It would seem like a reasonable and convenient process to have an NCRS managed and maintained "Judging Manual Updates" section on this website where information could be updated regularly and downloaded as needed. This format would also facilitate use of color pictures and related materials. Perhaps it's time for NCRS to make some changes to way things used to be done.

[William C.]

Re: 1972 Closed Air Filter Element Technical Description Clarification

One thing to note is that the air filters were shipped with the air cleaner, and not separately to the assembly plant (per the AIM) so that adds another level of confusion to identifying an "original"

[Terry M.]

Re: 1972 Closed Air Filter Element Technical Description Clarification

.???? What?

I initially typed "I agree" but the computer requires more words and letters than that phrase, so i typed more, and more, and more.

[Terry M.]

Re: 1972 Closed Air Filter Element Technical Description Clarification

Couldn't updates be posted on this site?

I will tell you one of NCRSs dirty little secrets: The income from advertising in The Driveline and selling Judging Manuals underwrites many of NCRSs other activities. Anything, like posting updates on-line, that will reduce that income is just not going to happen.

[Rick M.]

Re: 1972 Closed Air Filter Element Technical Description Clarification

Charge for the updates!