"Over the years a number of Model T engine numbers and casting dates have been collected from members of the Model T Ford Club of America and other sources. The main reason for this effort was to compare the casting dates with the dates of the engine assembly.
For years it had been presumed that the engine castings were “aged” for some time before they were machined and assembled into complete engines. Based on the examples collected, this was far from the case. While some of the engines were assembled much later than they were cast, some were assembled the same day they were cast. There appears to be no real planned aging period; it is as if the castings were piled in a heap and then removed in a random fashion.
There are a number of questionable entries in our compilation. Quite a few engines were apparently assembled before their blocks were cast! Even with Ford’s well-known efficiency, this must have been a difficult task!
There are a number of possible reasons for this seemingly impossible situation.
(1) The original engine had failed and its serial number was stamped on a replacement engine.
(2). The block was cast, machined, and then shipped to another assembly plant where the serial number was affixed. It is a known fact that the Highland Park plant shipped blocks of engine number certificates to branches where engines were assembled. If an engine was cast after a group of numbers had been shipped, it is easy to see how such serial numbers could pre-date the casting date.
(3). It is possible that the serial number and/or casting date was not clear and that the person who tried to read them was in error.
Interestingly, not all Model T engines had casting dates. It seems that, apparently, some of the foundry cores had provision for dating while others did not. The accompanying compilation generally lists only those engines that do have a casting date except in a few cases where some feature, such as the water jacket plugs, aids in dating a change in design.
No engines were found with casting dates after December 1921. This was at the time the one-piece valve door was introduced and
perhaps the dating was discontinued with this redesign of the cylinder casting.
While requesting serial numbers and casting dates we also asked for information on various features of the engines, such as the type of water jacket plugs and whether the engine had open valves, two or one piece valve doors, etc. Returned data was a bit confusing; apparently some of the owners were not aware of the difference in the jacket plugs (pipe vs welch) and submitted the wrong information. For example, more than one engine was noted as having pipe plugs as late as 1915. Some of these had earlier casting dates but others were cast in 1915, long after the welch plugs became standard.
In any event, it appears that the welch plugs began in mid-1913 and both pipe and welch plugs were used for almost a year. No pipe plugs, except for those noted above, were found after April 1914.
In conclusion, based on this data, the “aging” period for a Model T cylinder block was just long enough for it to cool down enough to be handled. Ford was building hundreds, even thousands, of engines each day. Setting these castings aside to age would hardly have been practical; you can imagine what a pile of one thousand blocks would take in space."
~ Model T Encyclopedia, Bruce McCalley
