Dating of Maxwells

[mrcvs]

My 1917 Maxwell contains '3-29-17-P3' on the engine block, which suggests that this is a date of manufacture of the engine block. I was talking with another Maxwell owner who owns a 1919 Maxwell and his has a date from Spring of 1919 (he could not remember the exact date). Additionally, I own an engine with 10-20-15-P3 stamped on it, which suggests 1915 manufacture. It seems too much of a coincidence that this is NOT the date of manufacture of the engine block, and it is assumed the date of manufacture of the car is of a similar date. Any out there who agree (or disagree) with me? Any ideas as to what the P3 means?

[JV Puleo]

It seems more likely that it is a foundry casting date. That would have been important because the castings were allowed to stand for some period of time... maybe 6 months before they could be machined without warping. So, a March 1917 date probably is a 1917 car but an October 1915 date would be a 1916 car. This was empirical engineering. They understood that aging the castings was needed but not what the problem was. (It has to do with stress relief. Later it would be learned that this could be done by controlled heating and cooling.) If this is the case, having the actual date on the casting makes a lot of sense because otherwise it would probably impossible to tell one lump of rusty iron from another.

[mrcvs]

JV Puleo--Relative to my Maxwell, this actually makes lots of sense! In 1917, serial numbers started at 113,206 and ended at 193,800. Mine is in the 169,000 range. If one interpolates this data, it suggests this car was produced around September of 1917, which is 6 months after the engine was cast. Thank you for your insughtful information!