I have two oil pans removed from 1930 Pierce-Arrow 8-cylinder engines. They are identical except for the bump at the back of one of them. (See photo.) Someone told me that this bump provides clearance for the No. 8 rod on the Model A engine. The stroke on this engine is 5” (also on the 1931 Model 41 and 42) but the stroke for the 1929 and other 1930 engines is 4 ¾”. The connecting rods falls 1/8” lower on the 5” stroke engines.
HOWEVER, one 1930 Model A owner tells me his pan has the bump, and another 1930 Model A owner says his two don’t! I would be very interested to know if any other 1930 or 1931 Pierce owners see this bump at the back of their oil pans, and on what models. Any information will be appreciated.
I was going to guess the pan with the bump out is for the 1930 series c and 1931 series 43 for the timing gear cam drive set up. I checked part numbers for 1931 and it lists series 41&42 AS #723316, and the series 43 as # 744394. Even the gaskets for the oil pans have diffrent part numbers. My 29 and 30 parts catalog are at the shop, if I remember I will look it up tomorrow. The info provided by the 1930 owners is interesting. I will also check my 1930 series a & b engines as well as my 41,42 and 43 that are in the shop to see what they have.
Oil pan part number for 1929 as well as all of the 1930 series engines was #123316, although there were 2 diffrent 29 styles due to the fact early 29 motors had a diffrent oil dump / drain for the rear main seals. After looking at no less than 30 Pierce oil pans on the shelf today, I can report none of them had the bump out like the one in the photo above. Thus, I think the pan with the bump is early style 29. I also checked the spare motors in the racks; as well as my 31 series 42 and 32 series 54 along with a bunch of spare engines from 29 to 37 and none of them had the bump out either.
My car is a late ’29 (Nov. ’29 build date) and the pan does not have the bump.
I have a 1930 model B. I will check tomorrow to see if it has the bump
No bump on my model B