No, no, no, you have the serial number confused with the casting Date Code ID Tag -two different animals. There is NOTHING in a serial number that indicates model date other than the serial number range in which year the engine only would have been assembled and tested. Serial numbers were meant to also coincide with the tractor when they were assembled. You have a engine serial number of *8N-I27694* which would be a 1949 engine. FORD used the capital letter 'I' to indicate the numeral #1. They used the lower case letter 'b' to indicate the numeral #6 and an inverted lower 'b' to indicate #9. It has nothing to do with SEP 27 and there is no funny zero. The DATE CODE ID TAG is a band attached to the sand casting mold on the starter pocket when they poured the block. What does your say? Should be a date code tag on the bottom of your aluminum hydraulic pump as well. Read on. Here's the correct story:
FORD SERIAL NUMBER IDENTIFICATION:
Heres how it worked: Engine blocks were cast at the Rouge Plant without any serial numbers stamped; serial numbers came later. Blocks were set aside in a hold area to cure for 30 days. Its just the nature of the beast. Cast Iron requires a 30 day green period of which to cure otherwise it is too brittle to machine. It is similar to seasoning wood. If you cut green wood, it wont burn. It must be seasoned for a period before it will burn. The next step was to pull engine blocks that have cured at random from the hold area to the machining area. Engine blocks got fully machined, cleaned, and then set in another hold area, still unmarked. Next, blocks got pulled at random to the engine assembly area where they were fully assembled and sent to yet another hold area. Once assembled, engines got pulled at random to the QC Test Area where they were put on special machines to be fully tested for function and gone through a lengthy break-in period. If, and only when the engine passed QC Inspection/Testing was it then given a hand stamped serial number by a worker and sent to another hold area at random, where it waited to be pulled for final assembly on the line. Serial numbers are stamped in sequential order in QC Testing, BUT, they are not maintained in any particular sequential order. A functional, assembled QC approved engine was of no concern to FORD for staying in any particular order. There could be a hundred assembled engines with same Date Code tag on them, but now would have a specific serial number stamped on them near the oil filter boss on the block. If at QC Testing an engine failed, it was either sent to a repair shop and retested or if unusable, would be scrapped out. Serial Numbers were hand stamped by a worker, often an inexperienced person with no technical skills and included handicapped and Negro personnel. Each character, letter, and numeral was stamped individually using a heavy hammer. If you recall the old DRAGNET TV show, at the end it always showed a mans brawny arm holding a heavy hammer and stamping a piece of steel with MARK VII LIMITED on it as the production company's trademark & logo. This is why N owners will often complain of unreadable serial numbers. The hands stamps could be weak or only partially visible. As the workers shift went on, fatigue would set in and the serial number wouldnt be hit as hard as others.
A serial numbers only purposes were to ID the engine block whose serial numbers were technically meant to ID the vehicle serial number as well. Since many blocks were swapped out, an 8N s/n engine block could have been switched out to a different 8N or even a 9N or 2N and vice versa. Note the date on this Service Bulletin. S/Ns were used on all Ford engines, not just tractors. Also, the capital letter I was used for the numeral 1; the lower case letter b was sued for the numeral 6 and the inverted b was used for the numeral 9. Before April, 1950 cylinder liners were made of steel and thus stamped with a STAR (*) prefix and suffix. Post 1950 Ford changed to cast iron sleeves and then changed to a DIAMOND (<>) symbol. Stars and diamonds mean nothing today as they no longer make steel sleeves, only cast iron. If you take your 9N to rebuild it and it still has steel liners, you will now get cast iron liners in your new rebuild kit and so never purchase new engine kit until you have the block stripped and boiled down. Then it can be measured with a precision gage and you can get the correct cylinder sleeve size, the correct pistons, and the correct bearings. You should also take your head and crank so your shop can deck the head if needed and regrind the crankshaft as well.
However, in the case of casting code date tag bosses used to identify casting part numbers; date of pouring; and/or foundry trademarks, the numerals used are a different character font from the serial number hand stamps. They should be because the method used on casting date code tag bosses is different than the hand stamp method. The characters and numerals are raised on a bar/band prepared prior to casting and inserted with screws in the sand mold prior to pouring. Remember the old label makers? It was a gun you could type a label on a special tape with an adhesive side so you could affix it to a drawer or equivalent to ID contents like SCREWS; NUTS; BOLTS. Each days production would have the same tag. It was how FORD could track green castings. My early s/n 1948 8N shows the engine casting code as I167. We know 8N production began in July, 1947, so a September 16, 1947 casting code would coincide. Don't assume because your engine casting code date boss shows a specific date, your tractor was built on that date, it wasn't. Only the engine block was cast on that date. Date Code ID Tags were also used on axle trumpets and the bottom of the aluminum hydraulic pump base. They should be within close proximity of the engine block tag. If not, one or the others may have been swapped out at some point.
One can only make a guesstimate as to a specific date your tractor was built if it wasn't adulterated, but know it is only a guess. Take the Date Code ID Tag and add 30 days. Thatll get you a pretty good window on when the tractor was fully assembled but it still does not ID any specific exact day and month. Tractor production was fast and furious so blocks did not sit around for too long. This is the best you can do, so as I always say, dont put too much faith on serial numbers. After the Hundred Series and Thousand Series came along they did stamp serial numbers differently.
FORD ENGINE BLOCK CASTING CODE DATE TAGS
JAN = A
FEB = B
MAR = C
APR = D
MAY = E
JUN = F
JUL = G
AUG = H
SEP = I
OCT = J
NOV = K
DEC = L
NOTE: Casting date codes do not use the hand stamps like engine serial numbers do -they are bands set up with standard alphabetical and numerical numbers and characters. They get riveted onto the block sand casting then poured. The Date Code ID Tag was affixed to the starter pocket as it was all part of the block. Each day got the same ID tag. The reason they coded the blocks is to track how long the cast blocks were held in 'green status'. Blocks were stored in a random manner. Cast Iron requires at least 30 days to 'cure' before it can be machined otherwise it is too brittle and will crumble and break tooling. It is an inherent property of cast iron. Equate it with the way wood has to be 'seasoned' before it can be burned efficiently. Green wood does not burn well. FORD Engine Block Casting ID Tag Numbers nomenclature: 1st a letter A-L denotes month; 2nd, a numeral from 1 thru 31 denotes the day of month; and 3rd, a single numeral denotes year block was cast. Example, I167 is coded as cast date September 16, 1947.
-Tim Daley
Certified Author and FORD TRACTOR Historian.
FORD ENGINE BLOCK SERIAL NUMBER HAND STAMPS:
FORD N-SERIES TRACTOR ENGINE BLOCK SERIAL NUMBER LOCATION:
EARLY 8N ENGINE CASTING DATE CODE BOSS, SEPTEMBER 16, 1947:
