CRG Discussion Forum
Camaro Research Group Discussion => Decoding/Numbers => Topic started by: bowtie68iho on December 19, 2010, 01:01:45 AM
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Does anyone know how to decode the date code on original AC oil filters? I've seen one with the date code "CJ22" in light blue screen print ink ( same color as other text) on the side. Is the "C" for Chevrolet? Is the letter "J" for the month begininng in January or the model year? Did the months skip the letter "I"? I assume the "22" is the 22nd day of whichever month is applicable.
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Does anyone know how to decode the date code on original AC oil filters? I've seen one with the date code "CJ22" in light blue screen print ink ( same color as other text) on the side. Is the "C" for Chevrolet? Is the letter "J" for the month begininng in January or the model year? Did the months skip the letter "I"? I assume the "22" is the 22nd day of whichever month is applicable.
A friend of mine worked at AC Engineering, and was a supervisor on the filter line for several years; I'll bounce this past him and see what he says, and post his response.
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Here's Don's response - he has conducted many NCRS Tech Sessions on AC oil filters, and has hundreds of them in his collection; do you have photos of the filter?
Pf-25's were painted white with blue silkscreening until mid-1974 with no date codes
Pf-25's were painted blue with paper/foil labels from late 1974 to early 1976 with no date codes
Pf-25's were painted blue with paper labels starting in mid-1976 with no date codes at least through 1982.
The first examples I have of what may be date codes are PF-25's in replacement AC-Delco boxes as follows:
Carton Date: 6-97 Code on filter: 274702 Could be: 274th day of 1997 2nd shift
Carton Date: 9-97 Code on filter: 349702 Could be: 349th day of 1997 2nd shift
Carton date: 8-01 Code on filter: 111J2 No idea what this means but believe they were made by a different manufacturer because the round emboss on the shell is smaller than the original filter
I also believe the 1969 Camaro from the factory had an emboss message on the end of the shell that was removed later.
To complicate things further, a version of the PF-25 was produced in Canada that had different silkscreening.
I would like to see pictures or a description of the filter in question.
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Check out:
www.1970z28camaro.com
This is an 1,100 mile car that never had an oil change. Original PF-25 is white with black silk screen, embossed on end.
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Check out:
www.1970z28camaro.com
This is an 1,100 mile car that never had an oil change. Original PF-25 is white with black silk screen, embossed on end.
That is an example of an assembly line oil filter. They go for over $350 when they become available.
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JohnZ, per your request, attached are three photos of a NOS 1968 PF-29 oil filter with date code "CJ22" on the side.
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Check out:
www.1970z28camaro.com
This is an 1,100 mile car that never had an oil change. Original PF-25 is white with black silk screen, embossed on end.
Not hi-jacking thread.... just that site gave me goose bumps. Never seen the white/black PF 25, but I do have a couple of the embossed white/blue in my parts bin.
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I understand the concours aspect of this, but why would you ever want to put a 40+ year old oil filter on your fine ride? The elements do/will deteroriate with time.
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Attached is another NOS PF-29 oil filter (6437946), but a different can design than the previous one I posted. I don't have the date code data on this one.
From what I read about the PF-29 oil filter in the Camaro Master Parts Manuals, it was the original factory oil filter for 1968 Camaros with V8 engines. The PF-25 oil filter (6438261) superseded the PF-29 filter and was available at least through 1973, if not later (one of my two Master Parts Manuals ends in July 1969, the other one ends in 1973).
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My theory on the date code is that the model year was used, not the calendar year. I arrived at this conclusion because the carton for the PF-29 oil filter only listed 1968 V8 engines...no other years. Assuming that the 1968 model year began in August 1967, here's how I decode "CJ22" on the filter:
"C" = Chevrolet.
"J" = April 1968 (if Letter "I" was skipped) or May 1968 (if Letter "I" was not skipped).
"22" = 22nd day of month.
I can't explain the two different PF-29 filters, though. Maybe one was a Canadian version?
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Here's Don's response to the PF-29 photos:
"I have two PF-29's in original AC boxes as follows:
Carton Date Code on filter
8- 67 N H 22
5- 68 H J 22
I have no idea what the code represents. N is the 14th letter ( or 13th if the I is not used)so it can't represent a month. In all my years at AC I don't recall
using a silkscreen for date coding a product."
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I'll be home in a day or so and I'll check the carton date on my filter and then post it. If enough people post their carton dates and PF-29 filter codes maybe we can crack the code.
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My 1100 mile 70 Z28 still had it's orig oil filter and it is white with black lettering, no blue on it. Absolutely the orig filter that was never off the car till I took it off.
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more
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JohnZ...Can you ask Don about mine ?
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JohnZ...Can you ask Don about mine ?
Yup, I'll pass the photos along for Don's review.
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Charley, here's Don's response on the 1100-mile '70 Z/28 oil filter photos:
"The white oil filter shell color, the black printing and the raised letter message appear to be correct for a 1970 model
Camaro. However, the length of the filter appears long. This may be due to the camera angle. The overall length should be 4.26 inches and the diameter inside the lockseam should be 3.524 inches. If possible, have the owner check these dimensions. If it is longer, it could be a PF-29 ( identified as a PF-25) that was used on 1968 model Camaros and Corvettes and replaced by the shorter PF-25 early in the 1969 model year. The PF-29 and PF-25 are functionally equivalent due to a "W" fold filter media design that permits the PF-25 to have the same internal surface area as the longer PF-29 that it replaces.
My analysis is based on the following AC engineering data:
The shell is white and the figures and letters are black until July 12,1970 when they were changed to a red AC "bulls' eye" and blue figures and letters.
On August 8,1968, the engineering drawings of the raised letter message was changed to " Best way to protect your engine replace with AC."
There is no documentation as to when these types of cosmetic changes are implemented in the vehicle assembly plant since they are not critical to the operation of the vehicle. Part inventory levels and tooling change lead times and other factors affect the actual implementation date."
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Yes my filter is the 4.26 and 3.524. You should probably amend your earlier post that left the black lettered filter out. So it sounds like late 70 cars might get the blue letters .
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I've been gone for a while, so I couldn't check my filter carton date until recently. The carton for my CJ22 code only had a single "9" or "6" on the bottom flap, no other numbers, so it could be 1966 or 1969. The vehicle applications listed on my carton are as follows:
BUICK 6 CYL. 1968
CHEVROLET 6 CYL. CHEVY II 1962-68
6 CYL. (EX. CORVAIR) 1963-68
V-8 CHEVY II 1964-68
V-8 ALL 1968
OLDSMOBILE 6 CYL. 1966-68
PONTIAC 6 CYL. TEMPEST 1964-65
STUDEBAKER 6 CYL. 1965-66
There is an NOS PF-29 filter on eBay. I queried the seller about the codes and dates on his filter. His code was JH22 and the carton date was "5-67". So, here's what we have so far:
Carton Date Code on filter
?- 66 C J 22
5- 67 J H 22
8- 67 N H 22
5- 68 H J 22
?- 69 C J 22
Was the carton made before or after the filter? How long before or after the filter? I see an early pattern above with the second letter appearing to be the year and skipping the letter "I". The pattern with the first letter also looks like it repeats itself, but must start some time in the middle of a year. The "22" carries over on every filter, so it must be a plant assembly code or something...unless the PF-29 filters were only made on the 22nd of every month (highly unlikely).
We need more examples from other CRG members to make any further hypotheses.
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I don't have any filter examples, but I was thinking maybe it's along the lines of the key codes with A and B for 67 and C D for 68 going up through the next model year and then starting all over again.
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The 22 is possibly the size of the rubber gasket. Has anyone found any other info on these over the past few years? I have a few from 79-80 down through 66 I can check.
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I just looked and my PF-11 has FF22 the carton date is 4/66