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I think you can count the 40's too. The fantastic, amazing, revolutionary 1949 Cadillac OHV V8 had the same horsepower as the 1940 Packard 356

And IMHO, the Packard 356 was a LOT better engine in almost all aspects. It WAS a Packard engine after all!

On the question of 3 ring aluminum vs 4 ring cast iron pistons anything I have to say would be pure speculation. I know nothing of the reasoning of the Packard board of directors or engineering department.

But it's always fun to second guess them so here goes.

3 ring aluminum pistons are better for speed and performanc, 4 ring iron are better for silence, low cost, low oil consumption, and long life.

Aluminum expands more than iron when hot. So aluminum pistons must be a loose fit in an iron cylinder when cold, if they are not to sieze up when hot.

Over the years various means of controlling expansion have been used such as, steel struts, T slots, grinding the piston oval, even wrapping the piston in piano wire.

But the aluminum piston is lighter than iron allowing the engine to rev easier.

3 rings vs 4. The 4th ring was an oil control ring. It is dispensed with on new cars because today's oil control rings are better than those of 80 years ago. But in those days many cars had 2 oil rings to better control oil burning. The disadvantage was the extra ring caused extra drag or friction. For better performance you could leave it out.

Piston design was not as developed back then, neither were rings, even the alloys of aluminum were softer.

I suspect they had problems with the aluminum pistons or that they did not live up to Packard standards of silence reliability and long life.

The iron pistons were the better choice for a luxury car at that time. Being the same material as the block, expansion and clearance problems did not arise. The 4 rings gave the best oil control for low oil consumption and long life between overhauls.

Later on when better pistons and rings became available they switched back to aluminum. Didn't Packard use Bohnalite pistons? Whatever pistons they used, of Packard design or from outside speciallists I expect they were the best available at the time.

Rusty, the engines I'm most familiar with, 6th thru 14 series senior eights, used 4 rings per aluminum piston but only 1 was an oil control ring, the other 3 were compression rings. Commencing with the 9th series the oil control ring was changed from 1/8 to 5/32 and that piston was supplied as the service replacement for the earlier engines.

Packard was an early advocate, perhaps the first, for aluminum pistons. Other than the very early cars, the only Packard I'm aware of that used cast iron pistons was 1942 as a result of war rationing of aluminum. Perhaps there were others that used cast iron, John raised the question so I suspect he has the answer to this.

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I am curoius. AFTER the war, were service replacement pistons also CI for the 42's or Al. What else was the '42 engine used for DURING the war years???

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This discussion is very impressive indeed. Here's just another V-12 tidbit:

The story as I read it of Enzo Ferrari's fascination with the Packard Twin Six stated that it was not the looks or even the configuration that made him strive to create a 12 of his own, it was the sound! He inquired about the sound before he knew what it was. (It was, as I recall, a racing Packard V-12.)

This account seems to be borne out in Ferrari's subsequent configurations of the 12, such as the flat opposed "boxer." It appears that the main requirement for Enzo was that it had 12 cylinders, no matter how they were arranged. 12 sounded the meanest to his ears, and unlike Packard's quest for silence, Ferraris were meant to be heard and, briefly, seen.

What is bore and stroke of the ferrari V12????? I'm guessing very small bore and a very long stroke.

Which Ferrari V12? You can find out all you need to know about them here.

In the book Packard by Dammann & Wren. It is stated that Packard introduced the straight eight on June 1923. On page 155 under the year 1924 reads the following.

( Slotted aluminum three ring pistons were used on early Straight Eights, but by December 1923 a switch was made to cast iron pistons with four top rings.)

John F. Shireman

Interesting and thanks for citing that reference, John. Don't forget the 1st and 2nd series eights were quite different from the 3rd series and those that followed. Different crankshaft design and different firing order for one thing to eliminate a periodic vibration. Of course cast iron pistons call for different crankshaft balancing than aluminum, so does your reference say they went to aluminum pistons in the 3rd series?