Engine Block Serial Numbers vs. Casting Date Codes

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Posted by Tim Daley(MI) on May 28, 2009 at 11:56:37 [URL] [DELETE] :

The method of identifying engine block serial numbers by Ford was done by a human worker after the block passed QC inspection using hand stamps (see picture) and therefore some numbers and characters didn't always get equal clarity. Many of us will remember the end of the old TV shows "Dragnet" and later, "Adam 12" which showed a medieval-type strong arm with a hand stamp that slammed a steel hammer down that read "Mark VII Limited". This is the same principle that was used for the N-Series Serial Numbering system and earlier vehicles- the ad says it is a Service Bulletin from 1931, so I assume this method was used on all Ford vehicles. The numerals 1; 6; and 9 were changed to letters I for numeral 1; lower case b for numeral 6; and an inverted lower case b for numeral 9 in the effort to help prevent falsifying a serial number. However, in the case of casting code date bosses used to identify casting part numbers; date of pouring; and/or foundry trademarks, the numerals used appear to be of a normal font from what I have seen. They should be because the method used on casting bosses is different than the hand stamp method. The characters and numerals are raised on a bar or band prepared prior to casting and inserted in the sand mold prior to pouring. I mention this because of the on-going discussion about Ford not using the letter I in numbering. The discussion centers around if and when "I" was used and if and when it was discontinued. My early s/n 1948 8N shows engine casting code as I167. We know 8N production began in July, 1947, so a September 16, 1947 casting code would coincide. Bear in mind that cast iron requires about a thirty day "curing" period, sort of like "seasoning" wood, before it can be machined otherwise it is too brittle and can create problems with machinery such as broken tooling as well as scrap castings. That being said, don't assume because your engine casting code date boss shows September 16, 1947 your tractor was built on that date, it wasn't. Only your block was cast on that date. Your tractor was built at least a month later.

Tim Daley(MI)
*9N653I* & *8NI55I3*

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