Engine Nameplate Specification Numbers (added March 2013)
The Waukesha Engine Historical Society is often asked about the meaning of the suffix numbers and letters stamped after the model designation on some older engine nameplates. These "dash suffix numbers and letters" were not part of the engine model designations; rather, they were used in conjunction with the basic model designation to identify a specific bill-of-material document for a specific engine model for a specific customer's order. In the lexicon of the company this bill-of-material document is referred to as a "specification", and the employees who wrote and kept a record of them were titled "Specification Writers". Waukesha thrived on repeat orders from the same customer, for the same engine with the same or similar options. When these repeat orders came in, all the Specification Writer had to do is go to the file, pull out the "specification" for that customer's repeat order for that engine model and run a copy for production.
The "specification" consisted of three parts:
- The first part was the basic engine model designation
- Then came a dash number taken out in numerical sequence for each individual engine model for each specific customer's order. Note: the dash was not always stamped on the nameplate.
- Lastly, there might be a suffer letter that served two purposes. Customers often ordered the same engine but with slightly different options requiring a different "specification" which was identified by a different suffix letter. Or, Waukesha might have made a change to a major engine component requiring a new "specification" suffix letter to keep track of the change. The letter "A" designated the first variation, the letter "B" the second variation, etc.
Let's decipher a couple of fictitious engine nameplates stamped with a "specification" to see how it works.
- 135DK-1 would be a "specification" for a Model 135DK Engine identifying the engine bill-of-material for this engine for a specific customer's order.
- 6MZA-68D would be a "specification" for a Model 6MZA Engine for a specific customer's order identified by the number "68" with the suffix letter "D" indicating there have been four variations in the "specification" as previously explained
Let's look at a real engine nameplate from an engine in our museum that is stamped with a "specification" to see how that works.
DU273 would be a "specification" for a Model DU Engine identifying the engine bill-of-material, 273, for this engine for a specific customer's order. Note there is no dash on this nameplate.
A customer ordering several of the same engines with the same options would be built to same "specification." But all engines are stamped with its own unique serial number which is used to identify other company documents particular to that engine, such as the "motor card" which documents production and testing information, including timing gear backlash flywheel run-out, etc. The engine's serial number is cross referenced with its "specification" in the company records.
Rocky Schaefer 2-2013
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