Packard Forum Index » Pre-War (1899-1942)

I have a 1939 Packard Six and unfortunately, had to pull the motor to get some engine work done. The SN is clearly stamped on the front upper side of the block, B26354A which shows it is a late engine for the 1939 model year.
The engine shop was ordering some parts and between them and the suppliers, after finding 3 18 48 embossed on the lower left, behind where the starter mounts, decided it was a 1948 engine

What is the 3 18 48 embossing , is it a date code for the block casting, and if so, why does the SN indicate a 39?

Note on the embossing two flat head screw casting which seems to me this was a removable part in the mold or was part of a tool that impressed this number into the sand casting

Thanks !

john

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One possibility is it might have been a service engine. There is a question -- at least in my mind -- as to how those were identified. Based on some weird motor numbers that people have reported I am thinking the service engines came unstamped in the normal spot. There was no uniform registration until much later so for states which registered by motor number during that era, a state (CA was one example) could specify a specific number or format to be stamped on replacement engines in place of the original number. Other states might have registered by the VN and not care about the motor number so the mechanic was free to stamp the original number on a replacement engine.

Are there any other stamped numbers you can find on the engine? Maybe someone knows where Packard placed the manufacturing ID or serial numbers on the inline engines before they were assigned a car. On V8s there was a manufacturing number that was stamped by the Utica plant at the rear of the block to ID the engine before it was in a car.

California does not register by engine number as such. If there is no VIN, then it can be used but it goes in the VIN field on the documents and it's best not to mention to the DMV that it is an engine number as they frown on it because engines get changed! Motorcycles are the only vehicles in California that use engine numbers but they still require the VIN too.

That said, I suspect Howard is dead-on that yours is a service replacement engine and if so, be careful of torques and that sort of thing. I once used a 1956 Motors Manual for a 1940 110 rod torque based on the chart in the book which went back to 1946. Apparently the postwar six cylinder engines used larger rod bolts so my smaller ones started to stretch every time I got them to the proper torque! Yours may have to be tighter than the 1939 specification but check the bolt size to be sure.

SN on head is very close to SN on block. Car was from Iowa, not certain they had such traceability there. Still has original VIN plate mounted on left side of cowl

"SN on head..."??

Cylinder heads didn't have serial or part numbers, just a casting number shared with all other heads cast from the same pattern.

I was about to ask the same thing! Curious comment.

Hey John,

Why not furnish the engine #, VIN # and anti-theft # as a set, and see if it falls into the known range for your year and model. I did that with my '39 Six and I think it was Dave (Owen_Dyneto) that came back with a list of known numbers in that range and mine fell right into the sequence, suggesting it was a) a '39 engine and b) probably original to my car. Chris

Have submitted engine SN, VIN and anti theft number and it came back all belonging to this car as it left the factory. I was quite pleased with that until I had to pull the engine out and while over at the machine shop, engine builder pointed out the "service" block date of manufacture. Heads and engine still at shop, but looking thru some photos I took, same date of manufacture is on head as well.

Car came from Iowa originally and had one additional owner prior to my Dad purchasing it. It had a pretty thorough stack of documentation with it (receipts, parts, service etc.) no indication anywhere that the block was replaced

Thought I had seen SN stamped on head, I'll look again in a week or so when I get the engine back

Since the casting date is postwar, it's clearly not the engine that came with the car. That much is obvious so it was apparently re-stamped with the same number as the original although I'm not sure what the letter at the end means, unless it was to differentiate it as a replacement.

I believe the "A" suffix to the motor number of a 1939 Six may indicate a factory substitution of a Borg & Beck for a Long clutch assembly. For the 1938 Six it indicated a cast iron camshaft substitution for the previous forged shaft.