THE GREAT OIL FILTER DEBATE

CURRENTLY I AM IN THE PROCESS OF PROCURING PARTS FOR A 1941 CHEVROLET SUBURBAN I OWN AND PLAN ON RESTORING SOMETIME IN THE NEAR FUTURE. ONE OF THE ITEMS I HAVE BEEN SEARCHING FOR IS THE CORRECT OIL FILTER ASSEMBLY FOR THIS VEHICLE. I KNOW WHICH ONE I NEED, BUT I HAVE FOUND THROUGH MY SEARCH, THAT EVERYONE I TALK TO HAS A DIFFERENT VERSION OF WHAT THEY THINK IS CORRECT FOR IT.

TO ADD TO THE PROBLEM, IN MANY CASES THE ORIGINAL CHEVROLET PARTS BOOKS USED ALONE, CAN LEAVE YOU WITH A PRETTY BIG GRAY FUZZY VOID, ESPECIALLY IF YOU DON'T HAVE THE ORIGINAL AC FILTER CATALOGS, AND OTHER SOURCE LITERATURE TO FILL IN THE BLANKS. SURELY OTHER FOLKS OUT THERE ARE FACING A SIMILAR PROBLEM, OR HAVE AT LEAST QUESTIONED IT, SO I DECIDED TO TRY TO COME UP WITH A DEFINITIVE ANSWER ON WHAT IS AND IS NOT CORRECT FOR SOME 1920'S 4 CYLINDER MODELS, AND 1930'S TO EARLY 1960'S CHEVROLET 6 CYLINDER CARS AND TRUCKS.

FORTUNATELY, BEING IN THE NOS PARTS BUSINESS, I HAVE ACCUMULATED WELL OVER 50 ORIGINAL CHEVROLET MASTER PARTS BOOKS FROM 1912 THROUGH 1982, NEARLY A DOZEN ORIGINAL AC OIL FILTER CATALOGS, MISCELLANEOUS PIECES OF ORIGINAL AC LITERATURE, AND MANY NOS AC OIL FILTER ASSEMBLIES AND ORIGINAL INSTRUCTION SHEETS. HOPEFULLY I'LL BE ABLE TO CLEAR UP WHAT IS TRULY CORRECT FOR THE 30'S THROUGH 60'S CHEVY'S TO MAKE YOUR RESTORATION A LITTLE EASIER. (OR LITTLE HARDER DEPENDING ON THE RARITY OF THE ONE YOU NEED FOR YOUR VEHICLE) PLEASE BEAR IN MIND THOUGH, THAT EVEN WITH ALL OF THE INFO I HAVE, THERE ARE STILL SOME OF THOSE GRAY AREAS LEFT CONCERNING WHAT IS TRULY CORRECT FOR SOME OF THE YEARS LISTED BELOW, ESPECIALLY SOME 1930'S MODELS, BUT SOME INFORMATION IS BETTER THAN NONE, SO I'LL SHARE WHAT I DO HAVE. I'LL TAKE IT YEAR BY YEAR TO TRY TO SORT OUT THE WHOLE THING AND MAKE IT EASIER TO REFER TO. THIS REFERENCE IS STRICTLY FOR CHEVROLET, BUT IF YOU NEED SOME INFO ON OTHER GM MAKES, DROP ME A LINE AND I'LL BE HAPPY TO SHARE WHAT I KNOW.

IT IS IMPORTANT TO NOTE THAT OIL FILTER ASSEMBLIES WERE NOT STANDARD EQUIPMENT ON PRE-1963 CHEVROLET CARS AND TRUCKS, EXCEPT FOR SOME 1920'S MODELS. CHEVROLET OFFERED OIL FILTER UNITS AS AN RPO (REGULAR PRODUCTION OPTION), OR AS A DEALER INSTALLED ITEM AVAILABLE THROUGH THE GM PARTS DIVISION. IN ADDITION TO THE AC UNITS SUPPLIED TO CHEVROLET, AC MADE MANY OTHER STYLES AND MODELS AVAILABLE THROUGH AC DISTRIBUTORS AND UNITED MOTORS SERVICE THAT WERE NOT OFFICIALLY MARKETED THROUGH CORPORATE CHEVROLET. I WILL BE DISCUSSING MANY OF THESE AC UNITS AS THEY PERTAIN TO PASSENGER CARS AND LIGHT/MEDIUM DUTY TRUCKS. I WILL NOT GO INTO THE HEAVY DUTY UNITS OVER 2 QUARTS, BUT IF YOU NEED INFORMATION ON THOSE UNITS, PLEASE CONTACT ME AND I'LL BE HAPPY TO SHARE THAT AS WELL.

IN ORDER TO HELP WITH THE IDENTIFICATION OF VARIOUS UNITS I WILL BE COVERING, I HAVE INCLUDED PICTURES, AND REFERENCES TO THOSE PICTURES THROUGHOUT THIS ARTICLE. ALL PHOTOGRAPHS OF ACTUAL UNITS SHOWN BELOW ARE OF NOS OIL FILTERS AND FITTING KITS TO MAINTAIN AS HIGH OF DEGREE OF ACCURACY AND AUTHENTICITY AS POSSIBLE. NONE HAVE BEEN REPAINTED OR RESTORED IN ANY WAY.

IF THERE'S ANYONE OUT THERE WITH ADDITIONAL ORIGINAL LITERATURE THAT I DON'T HAVE, OR NOS UNITS THAT THEY WOULD LIKE TO SHARE PICTURES OF TO HELP SHED MORE LIGHT ON THIS, PLEASE FEEL FREE TO CONTACT ME SO I CAN POST IT HERE FOR EVERYONE.

ALL REFERENCE MATERIAL USED IN THIS ARTICLE WAS TAKEN FROM THE FOLLOWING SOURCES:

1928, 1936, 1938, 1939, 1940, 1941, 1942, 1945, 1946, 1947, 1948, 1949, 1950, 1951, 1952, 1953, 1954, 1955, 1956, 1957, 1958, 1959, 1960, 1961, & 1963 CHEVROLET MASTER PARTS CATALOGS, AS WELL AS THE FOLLOWING AC MANUALS AND LITERATURE:

1932 AC PRODUCTS, UNITED MOTORS SERVICE CATALOG

1940 OIL FILTER INSTALLATION MANUAL DATED 4/1/1940

1940 AC L-1 OIL FILTER INSTALLATION INSTRUCTIONS DATED 4/1939

AC S-1 OIL FILTER INSTRUCTIONS DATED 4/1/1940

1940 AC PRODUCTS CATALOG DATED 5/1940

1941 AC PRODUCTS CATALOG DATED 1/1941

1941 AC L-1 & L-4 OIL FILTER INSTALLATION INSTRUCTIONS DATED 8/1940

AC OIL FILTER SHOP MANUAL DATED 11/1942

AC OIL FILTER SHOP MANUAL DATED 11/1945

AC OIL FILTER SPECIFICATIONS MANUAL DATED 7/1947

AC S-2 INSTALLATION INSTRUCTIONS DATED 10/1947

1947 AC SC-646 INSTALLATION INSTRUCTIONS

1948 AC OIL FILTERS AND ELEMENTS CATALOG

AC SC-650 INSTALLATION INSTRUCTIONS DATED 12/1951

1955 AC OIL FILTERS AND ELEMENTS CATALOG

AC SC-655 INSTALLATION INSTRUCTIONS DATED 10/1957

AC SC-255 OIL FILTER INSTRUCTIONS DATED 3/1957

AC SC-660 OIL FILTER INSTRUCTIONS DATED 11/1960

1964 AC OIL FILTERS AND ELEMENTS CATALOG

1927-1928

ACCORDING TO THE 1928 CHEVROLET MASTER PARTS BOOK, THE FILTER USED FOR ALL 1927 & 1928 CAPITOL AND NATIONAL CARS AND TRUCKS IS PART NUMBER 852690. ACCORDING TO THE 1932 AC PRODUCTS, UNITED MOTORS SERVICE CATALOG, IT IS A TYPE XA-3 CARTRIDGE. I RAN ACROSS THE PICTURES BELOW (IMAGE #1) THAT WERE ON AN ORIGINAL CHEVROLET SALESMAN'S FILMSTRIP WHICH SHOWED THE SELLING FEATURES OF THE 1928 CHEVROLET 4 CYLINDER LINE. THESE PHOTOS CONFIRM THE USE OF A FACTORY INSTALLED THROW AWAY AC CARTRIDGE TYPE FILTER, AND THE MOUNTING LOCATION BEING AT THE RIGHT HAND SIDE OF THE ENGINE, JUST ABOVE THE OIL PAN.

IMAGE #1

1927-28 AC TYPE XA-3

1929-1932

THE CHEVROLET PARTS BOOKS DO NOT LIST A FILTER AVAILABLE THROUGH CHEVROLET, BUT THE 1932 AC PRODUCTS, UNITED MOTORS SERVICE CATALOG STATES THAT A TAILORED PACKAGE WAS AVAILABLE THROUGH U.M.S. DEALERS. IT WAS SOLD UNDER AC NUMBER X-851670, AND WAS FOR ALL 1929-32 6 CYLINDER MODELS. (IMAGE #2) THE REPLACEMENT CARTRIDGE WAS AC PART NUMBER XD-2.

IMAGE #2

1929-32 AC TYPE XD-2

1933-1938

W-1 SERIES

THE 1936 CHEVROLET MASTER PARTS BOOK STATES THE FILTER UNIT FOR ALL 1933-36 MODELS EXCEPT CA, CC, DC & EC IS LISTED AS PART NUMBER 601465. SO BASICALLY, A FILTER WAS AVAILABLE FOR 1933-36 TRUCKS, 1935 MASTER PASSENGER CARS, AND ALL 1936 MODEL CARS AND TRUCKS. FOR WHATEVER REASON, THE APPLICATION DID NOT INCLUDE THE 1933 PASSENGER CARS AT ALL, NOR WAS IT FOR USE ON THE 1934 OR 1935 STANDARD PASSENGER CARS.

IT NOTES THAT A DIFFERENT OIL DISTRIBUTOR VALVE CAP #376843 AND GASKET #835905 ARE REQUIRED WITH THIS UNIT WHEN USED ON 1933-34 MODELS. THE NEW VALVE CAP HAD A THREADED HOLE TO ACCOMODATE THE OIL FILTER LINE FITTING. IN THAT SAME 1936 BOOK, IT LISTS PART NUMBER 852902 AS THE "REPLACEMENT UNIT" FOR 1933-36 MODELS CB, DB, O, P, EA, ED, EB, Q & R.

FROM WHAT I CAN DETERMINE FROM THE BOOKS, THE 601465 UNIT PROBABLY INCLUDED ALL OF THE FITTINGS, HOSES/LINES, AND MOUNTING BRACKET. NO MENTION IS MADE AS TO THE AC MODEL NUMBER OF THE UNIT SUPPLIED.

THE ONLY CLUE AS TO THE MODEL OF THIS FILTER IS THAT THE AC OIL FILTER MANUALS I HAVE LIST AC FILTER W-1 AS BEING THE ORIGINAL EQUIPMENT FILTER FOR THOSE 1933-36 MODELS. IT WAS THEN SUPERCEEDED BY FILTER NUMBER W-21. (BOTTOM LEFT ON IMAGE #3)

IMAGE #3

L-1 SERIES (CENTER OPENING TYPE)

SEPARATE FROM WHAT IS LISTED IN THE CHEVROLET MASTER PARTS CATALOGS, AC OFFERED THE L-1 CENTER OPENING TYPE FILTER (IMAGE #4) AS A NEW INSTALLATION ON MOST AMERICAN AUTOMOBILES. IT COULD BE PURCHASED FOR CHEVROLET AS WELL, THROUGH AC AND UNITED MOTORS SERVICE DEALERS. IT USED A REPLACEABLE ELEMENT UNDER PART NUMBER L-11.

IMAGE #4

1939-1940

THE 1939 AND 1940 MASTER PARTS BOOKS DO NOT SHOW A FILTER BEING OFFICIALY OFFERED OR AVAILABLE FOR THESE TWO YEARS DIRECTLY FROM CHEVROLET. THE CHEVROLET DEALERSHIPS, SERVICE STATIONS, AND GENERAL PUBLIC, COULD HOWEVER PURCHASE THE AC MODELS L-1, AND S-1 (DESCRIBED BELOW) THROUGH UNITED MOTORS SERVICE FOR INSTALLATION ON PASSENGERS CARS AND TRUCKS.

1941-1946

DURING THE WAR, VEHICLES SUPPLIED TO THE MILITARY USED THE MILITARY STANDARD SENIOR AND JUNIOR TYPE FILTERS. FOR OBVIOUS REASONS I'M GOING TO COVER UNITS FOR CIVILIAN PASSENGER CARS AND TRUCKS ONLY FOR THESE YEARS, BUT IT IS IMPORTANT TO NOTE THAT THESE TWO MILITARY VERSIONS LATER BECAME THE S-2 & S-6 LINES RESPECTIVELY. (DISCUSSED IN THE 1946-48 SECTION)

S-1 SERIES

AFTER A TWO YEAR ABSENCE OF A FILTER BEING OFFICIALLY OFFERED THROUGH CHEVROLET, THE 1941 CHEVROLET MASTER PARTS BOOK STATES A FILTER WAS NOW AGAIN AVAILABLE UNDER CHEVROLET PART NUMBER 1503611. INITIALLY, IT WAS INTRODUCED BY AC IN 1939 AS AC MODEL S-1, AND WAS OFFICIALLY OFFERED THROUGH CHEVROLET IN 1941 AT A COST OF $6.50, WHICH WAS PRETTY EXPENSIVE FOR THE TIME. THE 1941 BOOK STATES IT COULD BE INSTALLED ON MODELS AS FAR BACK AS 1937, BUT TECHNICALLY WOULD BE CORRECT FOR 1939 TROUGH 1941 ONLY, AND FOR CHEVROLET PURISTS, IT WOULD BE PERMISSIBLE TO USE IT ON 1941 MODELS ONLY.

ALTHOUGH THE CHEVROLET MASTER PARTS BOOKS STATE THE APPLICATION AS "ALL", IT'S SALES WERE UNDOUBTABLY TARGETED PRIMARILY TOWARDS TRUCKS. THE AC OIL FILTER INSTALLATION SHEETS PACKAGED WITH OTHER SMALLER CAPACITY MODELS OF THE TIME (SUCH AS THE L-1 & L-4) INSTRUCTED THE USER TO USE THE S-1 UNIT FOR TRUCK APPLICATIONS.

AS SHOWN IN THE INSTALLATION INSTRUCTIONS AT THE END OF THIS ARTICLE, THE S-1 UNIT WAS MOUNTED ON THE FIREWALL, AND USED A COMBINATION OF FLEXIBLE RUBBER HOSES AND COPPER TUBING TO TAKE THE OIL TO AND FROM THE ENGINE AND FILTER.

S-1 FILTERS WERE SUPPLIED IN TWO DIFFERENT VERSIONS. THE EARLY VERSION IS SHOWN IN IMAGE #5 & #6. IT HAD A 9" SHELL LENGTH, NEARLY 12" OVERALL LENGTH, AND USED GASKET #130. THE UNIT HAD A ROUNDED NECK AT THE BOTTOM, AND USED A T-HANDLE TYPE COVER BOLT.

IMAGE #5

S-1 1st. DESIGN

IMAGE #6

S-1 1st. DESIGN

THE SECOND DESIGN TYPE OF THE S-1 UNIT FIRST APPEARS IN THE APRIL 1, 1940 AC OIL FILTER SERVICE MANUAL, (IMAGE #7) BUT THE INSTRUCTIONS INCLUDED WITH IT STILL SHOW THE FIRST TYPE. THE SECOND TYPE HAD AN CONICAL BOTTOM RATHER THAN THE ROUNDED BOTTOM NECK DESIGN USED IN THE EARLY VERSION. IT WAS SLIGHTLY SHORTER IN LENGTH THAN THE EARLIER TYPE, AND THE TOP COVER WAS RETAINED BY A MORE CONVENTIONAL STYLE BOLT RATHER THAN A T-HANDLE.

IMAGE #7

S-1 2nd. DESIGN

I WOULD IMAGINE THAT DEPENDING ON INVENTORY LEVELS AT AC AT THE TIME, AND UNSOLD UNITS AT THE DEALERSHIPS, IT IS ENTIRELY POSSIBLE THAT SOME FIRST DESIGN UNITS COULD HAVE BEEN USED ALSO ON EARLY 1941 MODELS PRODUCED AND SOLD IN LATE 1940 AND EARLY 1941, ESPECIALLY SINCE THE FIRST AND SECOND DESIGN UNITS USED THE SAME PART NUMBER, SO STOCK COULD HAVE BEEN MIXED.

THE COLOR (OF BOTH STYLES) WAS AN ALUMINUM GRAY LACQUER, AND HAD A BLACK AND SILVER WATERSLIDE DECAL ON THE SIDE OF THE SHELL. BOTH THE EARLY AND THE LATE VERSION USED AC KLEER-KLEEN TYPE S-11 "IGNEONITE" FILTER ELEMENT. WHAT IS AN "IGNEONITE" FILTER YOU MAY ASK? (IMAGE #8) WELL, THE 1942 AC OIL FILTER SERVICE MANUAL STATES: "IGNEONITE IS A MINERAL WOOL MADE FROM ROCK WHICH IS MELTED AND BLOWN INTO FINE STRANDS. THIS IS MIXED WITH A RESIN BINDER AND MOLDED AROUND A PERFORATED CENTER CORE WHICH IS FIRST COVERED WITH SEVERAL LAYERS OF CANTON FLANNEL OR GLASS CLOTH. IT CONTAINS NO CLAY OR FULLER'S EARTH". THERE. NOW YOU KNOW.

IMAGE #8

"IGNEONITE" ELEMENT

THE ELEMENT NUMBER CHANGED TO C-113 AROUND 1944, AND WAS A COTTON TYPE. LATER, THE ELEMENT FILTER MEDIA CHANGED AGAIN TO A MORE MODERN PAPER TYPE IN THE 1950'S, AND WAS SOLD UNDER AC PART NUMBER P-113.

THE S-1 FILTER WAS OFFERED THROUGH CHEVROLET IN 1941, BUT THE 1942 AND THE 1945 CHEVROLET PARTS BOOKS DO NOT LIST A FILTER AVAILABLE THROUGH THE DEALERSHIP AT ALL FOR 1942 MODELS. HOWEVER, AC STILL OFFERED THE S-1, AS WELL AS THE L-1 AND L-4 UNITS FOR 1940-1942 PASSENGER CAR AND LIGHT TRUCK MODELS THROUGH AC DISTRIBUTORS AND UNITED MOTORS SERVICE (SHOWN IN THE NEXT 2 SECTIONS).

L-1 SERIES

AC OFFERED SEVERAL STYLES OF FILTER FOR 1939-46 CARS AND TRUCKS IN ADDITION TO THE S-1 UNIT DESCRIBED ABOVE AND SOLD THROUGH CHEVROLET DEALERSHIPS. THE REDESIGNED AC KLEER-KLEEN L-1 SERIES WAS OFFERED FOR CHEVROLET PASSENGER CARS AND LIGHT TRUCKS. THE NEW DESIGN WAS A TOP OPENING UNIT, RATHER THAN A CENTER OPENING UNIT.

AC MADE TWO DIFFERENT VERSIONS OF THE TOP OPENING L-1 SERIES. A DRAWN SHELL TYPE, AND A WELDED SHELL TYPE WERE BOTH SOLD UNDER THE L-1 SERIES DESIGNATION. THE WELDED SHELL TYPE WAS BASICALLY TWO PIECES WELDED TOGETHER WHERE THE BOTTOM CAP MET THE SHELL BODY, AND THE SHELL HAD A ROLLED LIP UNDER THE COVER. (IMAGE # 9)

IMAGE #9

FIRST TYPE TOP OPENING L-1 FILTER (WELDED SHELL)

THE DRAWN SHELL TYPE WAS ONE PIECE OF STAMPED STEEL FORCED BY A PLUNGER THROUGH A SERIES OF PROGRESSIVELY SMALLER DRAWING DIES TO FORM THE BOTTOM AND SIDES AS ONE UNIT. THE LIP UNDER THE TOP WAS THE SAME DIAMETER AS THE SHELL BODY. (SEE IMAGE # 10)

IMAGE #10

SECOND TYPE TOP OPENING L-1 FILTER (DRAWN SHELL)

THROUGH MY RESEARCH, IT APPEARS THAT THE WELDED STYLE WAS USED FIRST, IN OR AROUND 1939, AND BY 1941 THE DRAWN CUP TYPE WAS THE UNIT PREDOMINANTLY PRODUCED AND SOLD. AS WITH THE MID YEAR CHANGE TO THE S-1 SERIES, IT COULD BE ENTIRELY POSSIBLE THAT SOME FIRST DESIGN L-1 UNITS COULD HAVE BEEN USED ON SOME 1941 VEHICLES. IN FACT THE INSTRUCTION SHEETS FOR 1941 AND 1942, AS WELL AS THE 1941 OIL FILTER BOOKS, STILL SHOW THE WELDED TYPE WHICH WOULD INDICATE THERE WAS SOME OVERLAP BEFORE THE WELDED SHELL TYPE WAS PHASED OUT COMPLETELY.

THE COLOR FOR BOTH VERSIONS WAS AN ALUMINUM GRAY LACQUER, AND HAD A BLACK AND SILVER WATERSLIDE DECAL ON THE SIDE OF THE SHELL. THE DECALS WERE NOT THE SAME FOR BOTH STYLES THOUGH. LOOKING CLOSELY AT IMAGE #9 & #10 OF TWO NOS UNITS SHOWS THE WORDING BEING DIFFERENT IN REFERENCE TO THE GASKET USED.

BOTH VERSIONS WERE ORIGINALLY SUPPLIED WITH AN "IGNEONITE" ELEMENT, # L-11. AROUND 1944 IT WAS CHANGED TO A COTTON ELEMENT PART NUMBER C-112, AND WAS AGAIN CHANGED TO THE P-112 PAPER TYPE YEARS LATER. GASKETS WERE DIFFERENT IN ALL THREE VERSIONS PRODUCED OF THE L-1 (IMAGE #11).

IMAGE #11

UNLIKE LATER STYLES OF THE 40'S & 50'S, THIS FILTER WAS NOT MOUNTED TO THE INTAKE MANIFOLD CROSS RUNNER FORWARD, OR REAR OF THE MANIFOLD HEAT STOVE. THE CHEVROLET BRACKET & FITTING KIT #4 (SHOWN IN THE MOUNTING KIT SECTION) MOUNTED DIRECTLY TO THE FACE OF THE MANIFOLD HEAT STOVE. THE TOP PORTION OF THE BRACKET HAD A SINGLE HOLE, AND THE BOTTOM PORTION HAD TWO HOLES. THE L.H. CARBURETOR STUD NUT AND THE TWO BOLTS ATTACHING THE INTAKE MANIFOLD TO THE EXHAUST MANIFOLD CLOSEST TO THE DRIVERS SIDE FIREWALL WERE REMOVED, THE BRACKET ATTACHED IN PLACE, AND THE NUT AND BOLTS WERE RE-ATTACHED. THE BRACKET HAD A SLOT FOR A 1" WIDE STRAP WHICH CLAMPED THE FILTER UNIT TO THE BRACKET. (SEE IMAGE #12 - PART #'S 853534 & 853434 AND THE L-1 INSTRUCTION SHEET FOUND AT THE END OF THIS ARTICLE).

IMAGE #12

ALTHOUGH THE S-1 UNIT WAS WHAT WAS OFFERED THROUGH THE CHEVROLET PARTS DEPARTMENTS FOR 1941, THE L-1 AND L-4 SERIES (L-4 SERIES IS DISCUSSED IN THE NEXT SECTION) WAS AVAILABLE THROUGH AC DISTRIBUTORS AND UNITED MOTORS SERVICE. STARTING IN 1941, AC OFFERED A DIFFERENT STYLE BRACKET FOR USE ON TRUCKS ONLY (EXCEPT COE MODELS) FROM 1937 TO 1946 UNDER PART NUMBER 4-T (IMAGE # 13 & # 14) WHEN USING AN L-1 OR L-4 UNIT. IT ATTACHED TO THE HORN MOUNT ON THE MANIFOLD IN THE FRONT, AND TO THE INTAKE/EXHAUST MANIFOLD AT THE REAR. TECHNICALLY, THIS WOULD BE A RETROFIT FOR PRE 1941 TRUCKS, AND WOULD ONLY BE CORRECT FOR USE ON 1941-46 MODELS WHEN USING THE L-1 AND L-4.

IMAGE #13

L-1/L-4 MOUNTING BRACKET FOR TRUCK

IMAGE #14

L-4 SERIES

THE L-4 SERIES WAS FIRST INTRODUCED IN 1940. IT HAD A DRAWN SHELL AND WAS A SMALLER VERSION OF THE L-1 SERIES, BEING THE SAME DIAMETER, BUT SHORTER IN LENGTH. IN THE 1941 AC OIL FILTER CATALOG IT WAS ADVERTISED AS "A LOW PRICED FILTER FOR SMALL PASSENGER CARS" (SEE IMAGE # 15 FOR AN EXAMPLE OF A UNIT WITH 1940/EARLY '41 LABELING).

IMAGE #15

L-4 1st. TYPE COLOR SCHEME & DECALS

THE ORIGINAL L-4 SERIES SHOWN IN IMAGE #15 WAS FINISHED IN ALUMINUM LACQUER AND HAD A BLACK AND SILVER "KLEER-KLEEN" DECAL ON THE SHELL WITH THE "L-4" MODEL DESIGNATION AND INSTRUCTIONS ON WHEN TO CHANGE THE OIL. THE LATER TYPE WAS PAINTED WITH A GRAY LACQUER RATHER THAN ALUMINUM, AND HAD A 2 ½" ROUND BLACK AND YELLOW "AC OIL FILTER" DECAL ON THE SHELL. (SEE IMAGE #16).

IMAGE #16

2nd. TYPE L-4 DECAL

LATER VERSIONS APPEARING AROUND 1946 WERE EXACTLY THE SAME IN CONSTRUCTION, BUT THERE WAS A SLIGHT CHANGE IN THE AC WATERSLIDE DECAL (IMAGE #17)

IMAGE #17

L-4 3rd. TYPE DECAL

BOTH OF THE LATER TYPE UNITS THAT WERE PAINTED GRAY HAD AN L-4 DECAL ON THE TOP. (IMAGE #18)

IMAGE #18

L-4 SECOND TYPE COLOR SCHEME LID

UNLIKE LATER STYLES OF THE 40'S & 50'S, THIS FILTER WAS NOT MOUNTED TO THE INTAKE MANIFOLD CROSS RUNNER FORWARD, OR REAR OF THE MANIFOLD HEAT STOVE. IT USED THE SAME BRACKETS AS THE L-1 WHICH MOUNTED DIRECTLY TO THE FACE OF THE MANIFOLD HEAT STOVE. THE TOP PORTION OF THE BRACKET HAD A SINGLE HOLE, AND THE BOTTOM PORTION HAD TWO HOLES. THE L.H. CARBURETOR STUD NUT AND THE TWO BOLTS ATTACHING THE INTAKE MANIFOLD TO THE EXHAUST MANIFOLD CLOSEST TO THE DRIVERS SIDE FIREWALL WERE REMOVED, THE BRACKET ATTACHED IN PLACE, AND THE NUT AND BOLTS WERE RE-ATTACHED. THE BRACKET HAD A SLOT FOR A 1" WIDE STRAP WHICH CLAMPED THE FILTER UNIT TO THE BRACKET. (SEE IMAGE #12 - PART #'S 853534 & 853434).

THE L-4 USED AN "IGNEONITE" ELEMENT, UNDER PART NUMBER L-14. THE COTTON VERSION APPEARED AROUND 1944 UNDER PART NUMBER C-110, AND WAS FINALLY CHANGED TO A P-110 PAPER ELEMENT.

1946 - 1948

S-2 SERIES

THE 1946 CHEVROLET MASTER PARTS CATALOG SHOWS THE PART NUMBER FOR 1946 AS BEING 1504439. IT ALSO STATES THAT IT IS TO BE USED FOR 1942 MODELS. TECHNICALLY IT WOULD BE A RETROFIT, AND NOT BE PERIOD CORRECT FOR '42, SINCE IT DID NOT EXIST AT THAT TIME. HOWEVER, IT STARTED IT'S LIFE AS THE MILITARY STANDARD SENIOR FILTER USED DURING THE WAR ON MILITARY VEHICLES PRODUCED BY GM.

TO THROW A LITTLE SNAG IN ALL OF THIS, THERE IS NO FILTER LISTED FOR 1947 VEHICLES IN THE 1947 CHEVROLET MASTER PARTS CATALOG. HOWEVER, IT STILL LISTS THE 1504439 AS BEING THE UNIT FOR 1942-46 MODELS THOUGH. THE 1948 CHEVROLET CATALOG LISTS THE 1504439 UNIT AS BEING THE CORRECT ONE FOR 1947 AS WELL, SO I'M GOING TO ASSUME IT WAS SOME SORT OF MISTAKE THAT ONE DID NOT APPEAR IN THE '47 BOOK AND THE OVERSIGHT WAS CORRECTED IN THE '48 BOOK. SOMETIMES YA JUST GOTTA LOVE GM.....

ONE THING IS FOR SURE THOUGH. THE 1504439 UNIT IS AN AC MODEL S-2 FILTER ASSEMBLY, WHICH WAS THE REPLACEMENT FOR THE NOW DISCONTINUED S-1 UNIT. ALTHOUGH THE BOOKS SAY "ALL EXCEPT COE" IT IS GEARED MORE TOWARDS TRUCKS I BELIEVE, RATHER THAN THE PASSENGER CARS, SIMPLY BECAUSE OF THE SIZE OF THE UNIT. THE S-2 UNIT IS LARGE, AND IN MY OPINION BEING NEARLY 2 QUARTS, IS A LITTLE BIT OF AN OVERKILL FOR CAR USE. IT HAS A HEIGHT OF 11 5/8", WHICH WAS A LITTLE TALLER THAN IT'S PREDECESSOR THE S-1, AND THE O.D. WAS 5" DIAMETER, AS OPPOSED TO THE S-1'S DIAMETER OF 4 5/8". THE CHEVROLET PURCHASED UNIT WAS MOUNTED TO THE FIREWALL WITH THE 2 STRAPS SUPPLIED WITH IT. THE STANDARD VERSION SUPPLIED BY AC ALSO MOUNTED TO THE FIREWALL WITH THE 2 STRAPS, OR COULD BE MOUNTED ON THE INTAKE MANIFOLD RUNNER BY ADDING THE CORRECT BRACKET SET, WHICH WAS THE SAME AS THE ONE USED FOR THE S-6 MODELS DESCRIBED BELOW AND SHOWN IN THE BRACKET SECTION AT THE END OF THIS ARTICLE.

THE ORIGINAL 1946 UNIT WAS GRAY, AND HAD A 2" DIAMETER YELLOW AND BLACK "AC OIL FILTER" DECAL ON THE SHELL. (SEE IMAGE # 19)

IMAGE #19

(S-2 ORIGINAL GRAY COLOR SCHEME USED TO JULY 1947)

BY MID YEAR 1947, THE COLOR SCHEME CHANGED FROM ALL GRAY TO YELLOW WITH A BLACK TOP. (SEE IMAGE #20 & 21)

IMAGE #20

(S-2 YELLOW & BLACK COLOR SCHEME USED FROM JULY 1947 THROUGH 1949)

IMAGE #21

(S-2 KLEER-KLEEN DECAL USED FROM 1946 THROUGH 1949)

THE S-2 SERIES WAS USED UP TO 1962 AS AN ALTERNATIVE HIGHER CAPACITY UNIT TO THE S-6 FOR LARGER TRUCKS AND BUSSES. IN 1950 THE COLOR SCHEME CHANGED, TO HAVING AN ORANGE LID AND BLUE BODY.

THE S-2 UNIT INITIALLY USED A C-25 FILTER ELEMENT, WHICH WAS CHANGED TO A C-117, (COTTON) AND FINALLY TO P-117 (PAPER) ELEMENT.

L-5 SERIES

THE L-5 SERIES WAS OFFERED THROUGH AC, AND WAS ONLY USED FROM 1945 THROUGH 1948, AND WAS NEVER MARKETED OR OFFERED THROUGH CHEVROLET. IT HAD A LARGER CAPACITY THAN, AND REPLACED THE L-4 UNIT, AND HAD A COMPLETELY DIFFERENT MOUNTING BRACKET. IT COULD BE USED ON THE 1937-1942 MODELS, BUT WHEN IT WAS, THE MOUNTING BRACKET WAS IN A DIFFERENT LOCATION THAN LATER YEARS. A FLAT BRACKET WAS HELD TO THE INTAKE MANIFOLD HEAT RISER BOX BY MEANS OF TWO U-BOLTS, ONE ON EITHER SIDE OF THE BOX. THE 2" WIDE SHELL BRACKET WAS TIGHTENED ON TO THE SHELL, AND THE WHOLE ASSEMBLY BOLTED TO THE FLAT BRACKET USING TWO SPECIAL U-BOLTS TO KEEP IT ALL TOGETHER. IN 1946, THE INTAKE MANIFOLD WAS CHANGED ON THE CHEVROLET'S, AND THE THREADED HOLE FOR THE WIPER VACUUM CONNECTION WAS MOVED FROM THE FIREWALL SIDE OF THE MANIFOLD TO THE L.H. INNER FENDER SIDE. BECAUSE OF THIS, THE FILTER LOCATION CHANGED ON THE 1946 TO 1948 MODELS FROM BEING FASTENED ON EITHER SIDE OF THE MANIFOLD HEAT RISER BOX, TO JUST FORWARD OF IT SO IT WOULD NOT INTERFERE WITH THE NEW VACUUM CONNECTION LOCATION. THE COLOR OF THE 1946 AND EARLY 1947 UNIT WAS GRAY, AND A 2" DIAMETER YELLOW AND BLACK "AC OIL FILTER" DECAL WAS ON THE SHELL MOUNTING STRAP, RATHER THAN THE SHELL ITSELF (SEE IMAGE #22).

IMAGE #22

(L-5 GRAY COLOR SCHEME PRIOR TO MID 1947)

THE 1947-48 VERSION HAD THE SAME DECALS, BUT THE SHELL WAS YELLOW WITH A BLACK TOP. (SEE IMAGE #23 & 24)

IMAGE #23

(L-5 WITH YELLOW & BLACK COLOR SCHEME USED

FROM JULY 1947 THROUGH LATE 1948)

IMAGE #24

(L-5 BLACK TOP COLOR SCHEME USED

FROM JULY, 1947 THROUGH LATE 1948)

THE L-5 SERIES USED A C-111 COTTON ELEMENT INITIALLY, AND IT WAS LATER CHANGED TO THE P-111 PAPER TYPE.

S-6 SERIES

A NOTE ABOUT "S-6" SERIES FILTERS;

WHEN FIRST INTRODUCED, THE S-6 LINE WAS A UNIVERSAL FILTER THAT COVERED A WIDE VARIETY OF APPLICATIONS, INCLUDING NON-GM VEHICLES. THEY COULD BE PUT ON VIRTUALLY ANY VEHICLE AS LONG AS THE COORESPONDING BRACKET AND MOUNTING KIT WAS PURCHASED. STARTING WITH THE 646 SERIES, THE THREE DIGIT AC PART NUMBER SUFFIX MADE A LOOSE REFERENCE TO THE TYPE AND YEAR THE FILTER WAS FIRST INTRODUCED, BUT YOU MUST KEEP IN MIND THAT A NEW SERIES WAS NOT INTRODUCED EVERY YEAR, SO SOME FILTERS CARRIED OVER FOR MORE THAN ONE SELLING SEASON. THE PREFIX (SC) ALSO HELPED DENOTE MODEL AND TYPE. AN EXAMPLE FOLLOWS; TYPE SC-650 WAS AN "S" LINE FILTER. THE "C" DENOTED IT WAS A TAILORED KIT PACKAGED SPECIFICALLY FOR CHEVROLET APPLICATIONS. (KITS TAILOR MADE FOR CADILLAC USED A "K", "P" FOR DODGE, CHRYSLER AND PLYMOUTH APPLICATIONS, "F" FOR FORD, "N" FOR NASH), THE "6" DENOTED THE LINE TYPE. THE "50" ESTABLISHED WHAT MODEL YEAR IT WAS FIRST PUT INTO SERVICE. SO, SC-650 WAS AN S-6 TYPE, TAILOR MADE FOR CHEVROLET, AND FIRST INTRODUCED IN 1950. THIS SAME REFERENCING APPLIED TO OTHER TYPES AS WELL, SUCH AS THE 2 QUART S-2 LINE.

IN 1945, THE S-6 WAS INTRODUCED FOR USE ON CIVILIAN PASSENGER CARS AND TRUCKS AND WAS SOLD THROUGH AC AND IT'S DISTRIBUTORS. IT HAD STARTED IT'S LIFE AS THE MILITARY STANDARD JUNIOR FILTER THAT WAS USED ON SMALLER CUBIC INCH ENGINES ON VEHICLES GM BUILT DURING THE WAR.

FOR WHATEVER REASON, IT WAS NOT SOLD THROUGH CHEVROLET PARTS DEPARTMENTS AS AN APPROVED CHEVROLET DEALER ITEM UNTIL 1949. HOWEVER, FROM 1945 FORWARD, THE S-6 UNIT, AND VARIATIONS OF IT, WOULD BE THE FILTER UNIT THAT AC, AND LATER CHEVROLET, WOULD PICK AS BEING THE FILTER OF CHOICE FOR CHEVROLET CARS AND LIGHT TRUCKS WITH 6 CYLINDER ENGINES UP TO 1963 AS THE L-1, L-4 & L-5 WERE PHASED OUT.

THE MAIN CHANGES THROUGH 1949 WERE DECALS, AND COLOR SCHEME. THE S-6 UNIT HAD A HEIGHT OF 8 ½" AND WAS 5" IN DIAMETER WITH A FILTRATION RATE OF 16 GALLONS PER HOUR. THE BRACKET TYPE WAS THE SAME AS THE L-5 UNIT, WITH THE ONLY DIFFERENCE BEING A SLIGHTLY LARGER DIAMETER STRAP TO ACCOMODATE THE LARGER SHELL DIAMETER. WHEN USED ON MODELS PRIOR TO 1946 (WHEN USED AS A RETROFIT), THE S-6 UNIT WAS CLAMPED TO THE CENTER OF THE HEAT STOVE BY MEANS OF 2 SPECIAL U-BOLTS THAT CLAMPED ON EITHER SIDE OF IT. THE LOCATION FOR 1946 MODELS WAS FORWARD OF THE HEAT STOVE. LOOKING AT THE UNIT AS INSTALLED, THE FLAT BRACKET THAT THE STRAP IS MOUNTED TO, RESTED AGAINST THE FORWARD EDGE OF THE HEAT STOVE. THE LEFT SIDE OF THE FLAT BRACKET USED A SPACER IN BETWEEN THE BRACKET AND THE INTAKE MANIFOLD RUNNER. (BRACKET BR-13A) THE SPACER ALLOWED EVERYTHING TO BE MOUNTED PARALLEL WITH THE MANIFOLD. THE REASON FOR THE DIFFERENT MOUNTING LOCATION TO BEGIN WITH WAS THAT THE VACUUM CONNECTION FITTING ON THE MANIFOLD WAS AT THE REAR OF THE HEAT STOVE ON 1942 MODELS, AND ON THE SIDE OF THE HEAT STOVE STARTING IN 1946. AS I SAID THOUGH, THE PRE 1945 APPLICATIONS WERE A RETROFIT, AND THE S-6 UNIT WOULD NOT BE TECHNICALLY CORRECT FOR 1944 OR EARLIER MODEL USAGE.

FROM IT'S INITIAL RELEASE IN 1945 TO MID 1947, THE UNIT WAS GRAY WITH A YELLOW AND BLACK AC DECAL ON THE LID, AND THE 2" ROUND YELLOW AND BLACK "AC OIL FILTER" DECAL WAS LOCATED ON THE MOUNTING BRACKET STRAP (SEE IMAGE # 25). THERE WERE THREE DIFFERENT COLOR/WORDING SCHEMES USED ON THE LID DECAL. IMAGE # 26 SHOWS THE FIRST VERSION WHICH WAS USED FROM 1945 THROUGH THE MIDDLE OF 1946. IMAGE # 27 SHOWS THE SECOND TYPE LID DECAL THAT WAS USED STARTING AROUND THE MIDDLE OF 1946 TO EARLY 1947. THE WORDING REMAINED THE SAME. THE ONLY DIFFERENCE WAS IN INVERTED COLOR SCHEME ON THE LETTERING AND BACKGROUND. IMAGE # 28 SHOWS THE THIRD WATERSLIDE DECAL DESIGN THAT WAS USED. THE COLOR LAYOUT WAS THE SAME AS THE SECOND TYPE, BUT NOW THE WORDING CHANGED SLIGHTLY.

THE AC DESIGNATION FOR THIS UNIT PACKAGED FOR INSTALLATION ON CHEVROLET'S WAS SC-646.

IMAGE #25

(S-6 ORIGINAL GRAY COLOR SCHEME USED FROM 1945 TO MID 1947)

IMAGE #26

FIRST DESIGN DECAL USED ON THE EARLY GRAY

UNITS USED FROM 1945 TO MID 1946

IMAGE #27

2nd. TYPE LID DECAL USED ON THE EARLY GRAY UNITS

USED FROM 1946 TO EARLY 1947 (NOTE THE INVERTED

COLOR SCHEME COMPARED TO IMAGE #26)

IMAGE #28

THIRD DESIGN LID DECAL USED FROM EARLY 1947 TO MID 1947

(NOTE THE DIFFERENT WORDING COMPARED TO IMAGE #27)

STARTING IN JULY OF 1947, AC RELEASED THE "5 STAR OIL FILTER LINE". THE S-6 UNIT REMAINED THE SAME AS FAR AS SIZE, CONSTRUCTION, AND MOUNTING BRACKETS AS THE 1945- MID 1947 UNITS. THE ONLY DIFFERENCE WAS THE COLOR SCHEME OF THE BODY AND LID. THE S-6 UNIT WAS NO LONGER PAINTED GRAY AS IN THE EARLY MODELS. THE LID WAS NOW PAINTED FLAT BLACK, AND THE SHELL WAS A FLAT YELLOW (SEE IMAGE #29).

IMAGE #29

(S-6 YELLOW & BLACK COLOR SCHEME

USED FROM MID 1947 THROUGH 1949)

THE LID HAD THE SAME YELLOW AND BLACK DECAL, AND THE YELLOW AND BLACK 2" DIAMETER "AC OIL FILTER" DECAL ON THE SHELL CLAMP AS WITH THE GRAY 1946-EARLY '47 UNITS.

THE ELEMENT WAS A C-115 COTTON ELEMENT, LATER CHANGED TO P-115 PAPER TYPE.

LIKE THE EARLY GRAY S-6 UNITS, THERE WERE A COUPLE OF DIFFERENT WORDING SCHEMES USED FOR THE LID DECAL THAT TOOK PLACE BETWEEN MID 1947 AND 1949. IMAGES # 30 & 31 SHOW BOTH VERSIONS.

IMAGE #30

(FIRST TYPE DECAL FOR MID 1947 AND 1948 UNITS WAS THE

SAME AS THE THIRD DESIGN USED ON THE EARLY GRAY UNITS)

IMAGE #31

THE ADDITION OF THE PART NUMBER ON THE DECAL OF

THE REPLACEMENT ELEMENT USED, FIRST APPEARED

AND WAS USED ONLY ON 1949 UNITS

1949

SC-646 SERIES

STARTING IN 1949, THE CHEVROLET PARTS BOOK BEGINS TO OFFER A LITTLE MORE INFORMATION ON THE EXACT UNITS USED BY GIVING THE AC PART NUMBER, IN ADDITION TO THE CHEVROLET PART NUMBER. THE 1949 BOOK STATES THAT PART NUMBER 5571614 IS AN AC, SC-646 COMPLETE UNIT, AND IT CONTAINS THE S-6 FILTER. (SEE S-6 UNIT DESCRIPTION AND IMAGE #'S 29 & 31 SHOWN ABOVE) FIRST AVAILABLE THROUGH AC DISTRIBUTORS IN 1946, IT WAS NOW A DEALER INSTALLED ITEM FOR '49 AND COULD BE INSTALLED ON PREVIOUS YEAR MODELS.

THE C-115 COTTON ELEMENT WAS STILL THE REPLACEMENT OFFERED FOR THIS UNIT. THE UNIT STILL MOUNTED THE SAME WAY AS THE EARLIER S-6 UNITS WITH ONE BRACKET ON THE FORWARD RUNNER OF THE INTAKE MANIFOLD, AND ONE 2" HIGH STRAP ATTACHING THE SHELL TO THE BRACKET. IT ALSO STILL RETAINED THE YELLOW AND BLACK COLOR SCHEME THAT WAS USED STARTING IN MID 1947.

1950-52

SC-650 SERIES

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

STARTING IN 1950, THE CHEVROLET PARTS BOOK SHOWS THE P-115 PAPER ELEMENT, AND DOES NOT OFFER THE COTTON ELEMENT, ALTHOUGH THEY WERE STILL AVAILABLE THROUGH AC DISTRIBUTORS.

IMAGE #32

5572380/SC-650 UNIT

IMAGE #33

5572380/SC-650 TOP

1953 1954

SC-653 SERIES

FOR 1953 AND 1954, THE UNIT WAS REDESIGNED AGAIN, AND SOLD UNDER PART NUMBER 5573017. (SEE IMAGE # 34)

IMAGE #34

5573017/SC-653

THE '53 AND '54 CHEVROLET MASTER PARTS BOOKS FOR BOTH YEARS STATE THAT THE UNIT WAS NOW A SC-653 UNIT. THERE WERE MAJOR CHANGES TO THE UNIT ONCE AGAIN ALTHOUGH THE BODY ITSELF WAS THE SAME DIMENSIONALLY AS THE 1950-52 MODELS. THE SPOT WELDED BRACKET CHANGED COMPLETELY, THE INLET HOSE CONNECTION WAS AT A SLIGHTLY DIFFERENT POSITION IN RELATION TO THE SPOT WELDED BRACKET THAN PREVIOUS MODELS. AS FAR AS PACKAGE CONTENTS, THE INLET AND OUTLET HOSES WERE EACH 1" LONGER THAN THE PREVIOUS MODEL. THE SILKSCREENING ON THE LID WAS SLIGHTLY DIFFERENT. INSTEAD OF HAVING A BLOCK AREA TO WRITE THE MILEAGE IN, IT NOW HAD LINES. (IMAGE #35)

IMAGE #35

5573017/SC-653 TOP

1955-58

SC-655 SERIES

AC UNIT NUMBER SC-655 WAS THE NEXT GENERATION OF FILTERS IN THE S-6 SERIES. INTRODUCED IN 1955, IT WENT UNDER GM PART NUMBER 5573580, AND WAS USED ON 6 CYLINDER PASSENGER CARS AND TRUCKS THROUGH 1958. (IMAGE #36) THE ONE EXCEPTION TO THIS IS THE 1955 CHEVROLET 1st. SERIES TRUCKS, WHICH STILL USED THE SC-653 AC UNIT. THE SECOND SERIES TRUCKS USED THE SC-655.

THE SC-655 UNIT HAD A BRACKET SPOT WELDED TO THE SHELL LIKE THE PREVIOUS UNITS, BUT WAS SLIGHTLY DIFFERENT IN DESIGN. IT HAD A HALF MOON CUT OUT ON EACH SIDE TO BETTER CONFORM TO AND LOCATE ON THE INTAKE MANIFOLD RUNNER. THE OTHER MAJOR CHANGE TO IT WAS THAT THE INLET NOW ANGLED TOWARDS THE RADIATOR INSTEAD OF THE FIREWALL, AS IN PREVIOUS UNITS.

ALTHOUGH THE AC AND GM PART NUMBER DID NOT CHANGE, THERE WERE TWO VERSIONS OF THE SC-655 6 CYLINDER UNIT. SC-655 UNITS SUPPLIED FROM 1955 TO 1957 HAD A TOP LIKE WHAT WAS SUPPLIED ON THE EARLIER SC-653 UNIT. (SEE IMAGE #35 & 36)

IMAGE #36

1955-57 SC-655 UNIT

THE 1958 VERSION OF THE 6 CYLINDER SC-655 UNIT WAS THE SAME AS FAR AS THE BODY, BRACKET, AND INLET LINE LOCATION, (SEE IMAGE #37) BUT THE CAP WAS NOW SLIGHTLY SHORTER IN HEIGHT, AND THE STAMPED DEPRESSION EXTENDING TO THE SEALING LIP SURFACE WAS NOT AS DEEP OR PRONOUNCED. THE TOP RETAINING BOLT WAS ALSO DIFFERENT, AS THERE WAS NO SHOULDER UNDER THE HEAD AS IN THE 1955-57 VERSIONS. TECHNICALLY, THE ONE CORRECT FOR '55-'57 MODELS WILL HAVE THE FIRST TYPE TOP, AND THE 1958 UNIT WILL HAVE THE TOP SHOWN IN IMAGE #38, EVEN THOUGH BOTH WERE PACKAGED AS SC-655.

IMAGE # 37

1958 SC-655 UNIT

IMAGE #38

SC-655 UNIT WITH 1958 TOP

SC-6558 SERIES

1955 ALSO SAW THE INTRODUCTION OF THE SOON TO BE FAMOUS 265 CUBIC INCH CHEVROLET V-8. THE CHEVROLET PART NUMBER WAS 5573607 FOR THE 8 CYLINDER MODEL FILTER USED ON VEHICLES WITHOUT AIR CONDITIONING. THE AC MODEL DESIGNATION FOR THIS UNIT WAS SC-6558-1 ACCORDING TO THE PARTS BOOKS. THE V-8 FILTER USED ON MODELS WITH AIR CONDITIONING WAS CHEVROLET NUMBER 5573919 AND WAS MARKETED THROUGH CHEVROLET AS AN AC SC-6558-A UNIT (IMAGE #39).

IT'S INTERESTING TO NOTE THAT THE 1955 AC OIL FILTER CATALOG OFFERS MODEL SC-6558 TO FIT ALL V-8 EXCEPT 4BBL, CORVETTE, OR VEHICLES WITH AIR CONDITIONING, AND MODEL SC-6558-X TO FIT 4BBL. EXCEPT CORVETTE OR AIR CONDITIONING. THE AC FILTER BOOK MAKES NO MENTION OF THE "A" SUFFIX MODEL DESCRIBED IN THE CHEVROLET PARTS BOOKS.

1955 WAS THE FIRST AND ONLY YEAR THE V-8 ENGINE USED AN OPTIONAL EXTERNAL OIL FILTER. FROM 1956 ON, ALL CHEVROLET V-8'S HAVE USED AN INTEGRAL CARTRIDGE TYPE, OR MODERN DAY SPIN ON TYPE, WHILE THE 6 CYLINDER STILL USED THE EXTERNAL BOLT ON S-6 EXCLUSIVELY THROUGH 1962, AND SOME MODELS TO 1963.

THE P-115 PAPER ELEMENT WAS USED ON BOTH 6 AND 8 CYLINDER VERSIONS OF THE FILTER.

IMAGE #39

SC-255 SERIES

ALTHOUGH CHEVROLET STOPPED OFFERING THE S-2 SERIES AFTER 1948, AND WOULD NOT OFICIALLY OFFER IT AGAIN UNTIL 1959, IT WAS STILL AVAILABLE THROUGH AC. STILL A 2 QUART UNIT, IT WENT THROUGH THE SAME BASIC CHANGES AS THE S-6 LINE AS FAR AS BRACKETS, BODY TYPE, INLET HOSE LOCATION AND COLOR SCHEME. IMAGE #40 SHOWS THE SC-255 SERIES AVAILABLE FROM 1955 THROUGH 1958.

SC-255 UNITS SUPPLIED FROM 1955 TO 1957 HAD A STAMPED TOP WITH A SHAPE LIKE WHAT WAS SUPPLIED ON EARLIER S-2 (AND S-6) UNITS AS EXPLAINED IN THE SC-655 SECTION. UNITS MANUFACTURED STARTING IN 1958 HAD A STAMPED TOP STYLE LIKE THE ONE SHOWN IN IMAGE #38. TECHNICALLY, THE ONE CORRECT FOR '55-'57 MODELS WILL HAVE THE FIRST TYPE TOP EVEN THOUGH BOTH WERE PACKAGED AS SC-255.

THE ELEMENT USED IN THESE 2 QUART UNITS IS AC NUMBER P-117.

IMAGE #40

2 QUART SC-255 UNIT

1959

SC-659 SERIES

THE 1959 CHEVROLET PARTS BOOK LISTS THIS UNIT AS BEING PART NUMBER 5575218. IT WAS STILL THE TRIED AND TRUE S-6 UNIT WITH ONLY ONE MINOR CHANGE FROM THE 1958 UNITS. THE INLET LINE WAS NOW LOCATED 180 DEGREES OPPOSITE OF THE MOUNTING BRACKET, WHICH WOULD BE THE INNER FENDER SIDE OF THE FILTER WHEN INSTALLED. (SEE IMAGE # 41 & 42)

THIS UNIT STILL USED THE P-115 PAPER ELEMENT AS IN PAST S-6 MODELS.

IMAGE #41

1959 5575218/SC659 UNIT

IMAGE #42

5575218/SC659 TOP

SC-259 SERIES

1948 WAS THE LAST YEAR CHEVROLET OFFERED A 2 QUART UNIT ACCORDING TO THE MASTER PARTS BOOKS UNTIL 1959. HOWEVER, THE S-2 UNITS WERE STILL AVAILABLE THROUGH AC AND IT'S DISTRIBUTORS AFTER '48. STARTING IN 1959 THE S-2 WAS ONCE AGAIN OFFERED UNDER CHEVROLET PART NUMBER 5575217 AND CARRIED AC DESIGNATION AC-259. IT WAS EXACTLY THE SAME AS THE EARLIER UNIT (IMAGE #40) EXCEPT FOR THE FACT THAT THE INLET LINE WAS 180 DEGREES OPPOSITE OF THE MOUNTING BRACKET. IT USED AC FILTER #P-117 AS IN THE EARLIER UNITS.

1960-63

SC-660 SERIES

BEGINNING IN 1960, THE UNIT USED WOULD NOW BE CHEVROLET NUMBER 5576528, WHICH IS AC TYPE SC-660. (SEE IMAGE #43) THIS UNIT WAS EXACTLY THE SAME AS THE 1959 MODEL SC-659 IN PHYSICAL APPEARANCE AND LETTERING WITH THE EXCEPTION THAT THE INLET LINE CONNECTION WAS ON THE FIREWALL SIDE OF THE FILTER (AS INSTALLED), WHEREAS THE 1959 VERSION CONNECTED ON THE INNER FENDER SIDE (AS INSTALLED). THE TOP, AND THE LETTERING ON IT WAS EXACTLY THE SAME AS THE 1959 VERSION (SEE IMAGE #42).

IMAGE #43

1960-63 5576528/SC-660 UNIT

THE SC-660 FILTER TYPE WAS USED ON THE 1960, 1961, AND 1962 CHEVROLET 235'S AS WELL AS THE TWO QUART SC-260 UNIT DESCRIBED BELOW. THEY WERE BOTH DISCONTINUED FOR 1963 SINCE THE NEWLY INTRODUCED CHEVROLET 230 CUBIC INCH 6 CYLINDER ENGINE NOW USED A SPIN ON TYPE ELEMENT ELIMINATING THE NEED FOR THIS BOLT ON TYPE STYLE.

THE ONE EXCEPTION TO THIS IS THE 1963 CHEVROLET 4 WHEEL DRIVE TRUCKS WHICH RETAINED THE 235 ENGINE UNTIL MID YEAR 1963. ONCE THE 235 WAS FINALLY PHASED OUT, SO WERE BOLT ON OIL FILTER UNITS FOR USE ON CHEVROLET CARS AND TRUCKS FROM THAT POINT FORWARD.

SC-260 SERIES

THE 2 QUART UNIT WAS AVAILABLE THROUGH THE PARTS DEPARTMENT FROM 1960 THROUGH 1963 UNDER PART NUMBER 5576615 AND AC DESIGNATION SC-260. IT'S APPEARANCE WAS THE SAME AS THE UNIT SHOWN IN IMAGE #40 EXCEPT FOR THE INLET LINE LOCATION, WHICH WAS ON THE FIREWALL SIDE OF THE FILTER (AS INSTALLED).

MANY OF THE UNITS I'VE DESCRIBED HERE ARE ALL FAIRLY CLOSE IN STYLE. WHEN LOOKING ON EBAY, OR SCROUNGING AROUND AT JUNKYARDS OR CAR SHOWS TRYING TO FIND YOUR CORRECT UNIT, IT'S EASY TO GET ONE STYLE MIXED UP WITH ANOTHER. MANY OF THEM LOOK IDENTICAL, AND THE ONLY WAY TO TELL THEM APART IS BY SIZE. IMAGE #44 BELOW SHOWS MANY OF THE 1 QUART UNITS DISCUSSED HERE GROUPED TOGETHER TO GIVE YOU A BETTER IDEA OF THE PHYSICAL SIZE DIFFERENCES BETWEEN THE VARIOUS TYPES.

IMAGE #44

A WORD ABOUT FILTER ELEMENTS

THROUGHOUT THIS ARTICLE I HAVE REFERED TO SEVERAL TYPES OF FILTER ELEMENTS. IGNEONITE, COTTON, AND PAPER WERE THE THREE DISTINCT TYPES OF FILTER MEDIA THAT AC USED IN THEIR FILTERS OVER THE YEARS. THERE ARE SOME COTTON FILTER ELEMENTS STILL BEING SOLD BY PARTS STORES, BY FOLKS AT SWAP MEETS, AND ON EBAY. ALTHOUGH YOU MAY BE TEMPTED TO USE ONE OF THESE COTTON ELEMENTS, I WOULD HIGHLY RECOMMEND YOU STICK WITH A PAPER ELEMENT. BY AC's OWN ADMISSION, IN THE 1955 OIL FILTER MANUAL, THEY STATE THAT WHEN USING A COTTON ELEMENT, YOU CAN EXPECT TO SEE A PRESSURE DROP IN YOUR OILING SYSTEM. DUE TO THE CONSTRUCTION OF THE PAPER TYPE ELEMENTS, THERE IS A MUCH HIGHER FILTRATION SURFACE AREA AS OPPOSED TO THE COTTON, WHICH VIRTUALLY ELIMINATES PRESSURE DROP. WHEN USING A COTTON ELEMENT, AN ENGINE GENERATING 35 PSI OF OIL PRESSURE WILL SEE A 7 PSI PRESSURE DROP IN THE SYSTEM. CONVERSELY, WHEN USING A PAPER ELEMENT, YOU CAN EXPECT TO SEE ONLY A 1/100 th. OF A POUND PER SQUARE INCH DROP IN PRESSURE. KEEP THE OLD AC COTTON ELEMENT YOU'VE GOT AS A NEAT OLD DISPLAY ITEM IF YOU WANT, BUT DON'T STICK IT IN YOUR SHOW VEHICLE.

OIL FILTER LINES

WHICH OIL LINES ARE TECHNICALLY CORRECT IS JUST ABOUT AS CONFUSING AS THE FILTERS THEMSELVES. AC CHANGED MATERIALS AND COLORS QUITE OFTEN AS YOU WILL SEE IN THE EXAMPLE PICTURES. IMAGE # 45 AND #46 SHOW HOSES FROM THE ORIGINAL KLEER-KLEEN LINE PRIOR TO 1947. FOR THE HOSES PRIOR TO 1947, THE PART NUMBER DID NOT MATCH THE HOSE LENGTH. FOR EXAMPLE, HOSE NUMBER 27 WAS 20" IN LENGTH. ALSO, THE TWO NOS SAMPLES SHOWN ARE ENCASED IN DIFFERENT MATERIALS. IMAGE # 45 IS THE EARLY STYLE CLOTH BRAIDED TYPE HOSE, AND IMAGE #46 SHOWS THE LATER STYLE WHICH HAD A GRAY RUBBERIZED OR NEOPRENE CASING. DURING THAT SAME TIME PERIOD AC ALSO SUPPLIED COMPLETELY BLACK HOSES TOO.

STARTING IN 1947, THE PART NUMBER OF THE HOSE WAS ALSO THE LENGTH OF IT. SOME HOSES SUPPLIED WERE GRAY, BLACK NEOPRENE, OR YELLOW (IMAGE #20). MOST LATE 40's HOSES CAME WITH A PLASTIC BAND AROUND THE HOSE INDICATING THE PART NUMBER ALONG WITH A YELLOW AND BLACK AC CIRCLE LOGO (SEE IMAGE # 47). BY THE 1950'S ALL OF THE HOSES WERE BLACK AND THE LOGO BAND WAS STILL BLACK & YELLOW. THE ONLY DIFFERENCE IS THE BOX PACKAGING HAD CHANGED TO THE DOUBLE BULLSEYE LOGO. (IMAGE #48) STARTING IN THE LATE 50'S, THEY CHANGED FROM A PLASTIC BAND TO A STICKER WITH A RED AND WHITE AC LOGO AROUND THE HOSE SHOWING THE PART NUMBER. (SEE IMAGE #49). REPLACEMENT HOSES SUPPLIED THROUGH GM DEALERSHIPS IN GM PACKAGING RATHER THAN AC PACKAGING DID NOT HAVE THE BAND OR STICKER WITH THE PART NUMBER OF THE HOSE.

IMAGE #45

IMAGE #46

IMAGE #47

IMAGE #48

IMAGE #49

INSTRUCTION SHEETS

BELOW ARE SOME ORIGINAL OIL FILTER INSTRUCTION SHEETS.

S-1 INSTRUCTIONS PAGE 1

S-1 INSTRUCTIONS PAGE 2

L-1 & L-4 INSTRUCTIONS PAGE 1

L-1 & L-4 INSTRUCTIONS PAGE 2

SC-646 INSTRUCTIONS PAGE 1

SC-646 INSTRUCTIONS PAGE 2

S-2 INSTRUCTIONS PAGE 1

S-2 INSTRUCTIONS PAGE 2

1949 S-6/SC-646 INSTRUCTIONS-PAGE 1

1949 S-6/SC-646 INSTRUCTIONS-PAGE 2

1950-51 SC-650 INSTRUCTIONS

1952 SC-650 INSTRUCTIONS

1950-52 TRUCK SC-650 INSTRUCTIONS

(RETROFIT FOR MODELS PRIOR TO 1950)

1955 SC-655 INSTRUCTIONS

1955 SC-6558 8 CYLINDER INSTRUCTIONS

1955-58 6 CYLINDER SC-655 INSTRUCTIONS

1955-58 TRUCK 2 QUART SC-255 INSTRUCTIONS

1960-63 SC-660 INSTRUCTIONS

MOUNTING BRACKET KITS

L-1 & L-4 BRACKET USED

ON PASSENGER CARS

L-1/L-4 MOUNTING BRACKET FOR TRUCK - AC #4-T

(INSTRUCTIONS STATE 1938-46. BOX STATED 1937-41. IT IS ONLY CORRECT

FOR USE ON 1941-46 MODELS WHEN USING THE L-1 OR L-4 UNIT)

SC-6 MOUNTING BRACKET SET AC #K-127

(THESE PARTS ARE ALSO INCLUDED IN THE SC-646

COMPLETE UNIT. THIS KIT IS ALSO USED WHEN

MOUNTING THE 2 QUART S-2 UNIT TO THE MANIFOLD,

RATHER THAN THE FIREWALL)

I HOPE THIS HAS BEEN OF SOME USE AND VALUE TO SOME OF YOU OUT THERE. MY GOAL IN RESEARCHING AND WRITING IT WAS THAT THIS INFORMATION SHOULD CLARIFY WHAT IS AND ISN'T CORRECT FOR OUR VEHICLES FOR THOSE OF YOU LIKE ME, WHO ARE STICKLERS FOR AUTHENTICITY. IT WOULD ALSO BE NICE TO SEE THIS USED AS AN ACCA AND VCCA JUDGING AID, AS THERE IS NO DEFINITIVE STANDARDS OUT THERE AS TO WHAT IS AND IS NOT CORRECT OR ACCEPTABLE. I CAN'T TELL YOU HOW MANY TIMES I'VE SEEN A NICELY RESTORED CHEVROLET CAR OR TRUCK THAT HAD AN OIL FILTER ON IT FROM THE WRONG DECADE, THE WRONG COLOR, OR EVEN FRAM UNITS ON THEM THAT PEOPLE SWORE UP AND DOWN CAME FROM THE FACTORY THAT WAY.

ANOTHER REASON I WAS MOTIVATED TO DO THIS TYPE OF RESEARCH WAS THE FACT THAT MANY VENDORS OUT THERE ARE TELLING PEOPLE WHAT THEY HAVE FOR SALE FOR YOUR VEHICLE IS WHAT IS CORRECT FOR IT. EBAY SELLERS AND SWAP MEET VENDORS ARE THE WORLDS WORST AT THIS. WHENEVER YOU FIND AN OIL FILTER FOR SALE WITH THESE FOLKS, NO MATTER WHAT TYPE, THEY WILL USUALLY SAY THAT IT'S CORRECT FOR YOUR 1930'S TO 1960'S CAR OR TRUCK WHEN IN MOST CASES, NOTHING COULD BE FARTHER FROM THE TRUTH. IN ALL FAIRNESS TO THESE FOLKS, THEY ARE NOT ALWAYS TRYING TO INTENTIONALLY DECEIVE YOU SO YOU'LL BUY FROM THEM, THEY ARE JUST GOING BY WHAT THEY THINK IS CORRECT OR BY INSTRUCTIONS INCLUDED WITH ITEMS THEY'RE SELLING. FOR EXAMPLE, THE S-6 UNITS I HAVE DESCRIBED ABOVE, THAT WERE NOT INTRODUCED UNTIL THE '40'S, HAVE INSTRUCTIONS THAT SHOW INSTALLATION BACK TO THE '30'S. ALTHOUGH THESE INSTRUCTIONS SHOW THIS, THE UNITS ARE NOT CORRECT FOR THE '30'S APPLICATIONS SINCE THEY DIDN'T EVEN EXIST THEN. THE WAY I SEE IT, IF YOU KNOW WHAT'S RIGHT, YOU WON'T WASTE YOUR MONEY ON WHAT'S WRONG.

THE OTHER PROBLEM IS THAT REPRODUCTION PLACES PERPETUATE THIS THINKING. DECALS SOLD THROUGH THE REPRO PLACES DON'T ALWAYS GIVE THE CORRECT YEAR USAGE OR APPLICATION, NOT BECAUSE THEY'RE PURPOSELY TRYING TO DECEIVE YOU, BUT BECAUSE THEY HONESTLY DON'T KNOW ALL THE FACTS. I HOPE THIS ARTICLE GIVES YOU THOSE MUCH NEEDED FACTS.

ON THE OTHER HAND, DESPITE MY ARGUMENTS ON CORRECT VS. INCORRECT, THE ONE THING I NEED TO STRESS IS THAT ONE OF THE MOST IMPORTANT THINGS YOU CAN DO FOR YOUR RESTORED CHEVROLET STOVEBOLT 6, IS PUT AN OIL FILTER ON IT. WHEN IT COMES DOWN TO IT, WHETHER IT'S THE CORRECT ONE, A DIFFERENT YEAR, STYLE, OR ANOTHER AFTERMARKET BRAND, ULTIMATELY IT REALLY DOESN'T MATTER. JUST PUT ONE ON TO HELP PROTECT YOUR ENGINE, AND WE'LL ALL BE ABLE TO ENJOY EACH OTHER'S VEHICLES FOR MANY YEARS TO COME.

QUESTIONS? COMMENTS? ARGUMENTS TO THE CONTRARY OF WHAT'S WRITTEN HERE? EMAIL ME AT DDAUTOPARTS@MINDSPRING.COM I WILL ALSO BE HAPPY TO EMAIL FULL SIZE COPIES OF THE OIL FILTER INSTRUCTION SHEETS FOR VARIOUS AC UNITS FOR MANY GM MODELS AND YEARS FREE OF CHARGE.

Patrick Doonan

D & D Antique Auto Parts

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