1928 Model A crankshaft switchover

[JOHNCL]

Ford changed to a stronger crankshaft in late 1928. Does anyone know a more precise date? I have an October 1928 engine that I have not yet disassembled and i would like to know what to expect. Thanks in advance.

[Jack Shaft]

The earlier crankshaft is called a 'beavertail' crankshaft..the crankshaft throws look like a beavertail.Its two pounds lighter than the later one,which is a good thing.

[Kurt in NJ]

early crankshaft forged, later cast

[Gene F]

Hmmmm. Interesting.

[MikeK]

Both the early 'beaver' and later A crank were forgings. The change was made to reduce the number of die strikes and time to produce the part, as well as to reduce the sectional thickness changes that affect both heat treating and warpage. The result was a crank that was different, not necessarily better.

Cast cranks fall into several categories: Cast steel, cast white iron heat treated to produce 'malleable' iron (too soft), cast gray iron (fractures from shock in an internal combustion engine), and cast nodular or spherical carbon iron.

Ford, to this day, has never produced cast steel, gray iron, or malleable iron cranks. Only forged alloy steel and cast nodular iron.

Cast nodular iron is a technology did not appear until 1943. Cast nodular iron cranks are far superior to steel forgings in several ways. The primary advantage, beyond production cost, is their ability to absorb rather than transmit harmonic shock waves which snap forged cranks.

The majority of cars on the road to this day use cast nodular iron cranks. The exception would be the very high output engines, and then you have to trade off dealing with the 'rings like a bell' harmonics problem for the ultimate strength of a highly alloyed steel.

[Benson]

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As a kid in the early 60s I asked Bill Kenz for help with a loose rod bearing on the Coupe engine which had a "Beavertail" crank.

With a sly smile he said:

You know Sonny, that crankshaft makes your engine rev faster!

The Beavertail shape makes the crank cut through the oil vapor easier and increases horsepower!

[Benson]

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[J and M Machine]

Originally Posted by Jack Shaft

The earlier crankshaft is called a 'beavertail' crankshaft..the crankshaft throws look like a beavertail.Its two pounds lighter than the later one,which is a good thing.

Not really:
Since we've been doing Model A engines along time. We've seen more of the beaver tail cranks cracked than the 1929 and on versions.

[Chuck Sea/Tac]

I have a “virgin” beaver in the shop. Smiley face.
By that, I mean never turned. I may have another, in a engine I’ve never taken apart. It’s got a early pan with the clean out plate. I guess I could check the dates and see if it’s in the correct time period before the change.

[Jack Shaft]

Originally Posted by J and M Machine

Not really:
Since we've been doing Model A engines along time. We've seen more of the beaver tail cranks cracked than the 1929 and on versions.

Not really what? It isn't lighter? A wise man magnafluxes every used crankshaft,regardless of how many engines you build.

[J and M Machine]

Originally Posted by Jack Shaft

Not really what? It isn't lighter? A wise man magnafluxes every used crankshaft,regardless of how many engines you build.

Not really "A good thing because they are lighter."
as I mentioned we've seen more of these cranks cracked than the later ones.
We magnaflux all of our cranks that's how we know. I can't vouch for the other rebuilders out there.

[johnneilson]

No dog in this hunt, just a comment.
The weight and resultant MOI of the crankshaft is pretty inconsequential compared to the flywheel. Even a lightened one.
We know the initial crank in the Model "A" was experiencing potential bearing issues even before it went into production. According to Hicks, he suggested increasing the size before production.

John

[Jack Shaft]

The further from the point of axis the greater the gain from weight removed from the rotating group.

That the beavertail is two pounds lighter is fact,if you build with a cracked crank its on you.

Hicks and others pushed for a larger journal,Ford countered that flywheel mass was sufficient to deal with it..Ford won...With the 'new and redesigned four for 1932'. Engineering got their wish..Hicks was already on the skids by then, Ford found him to be impetuous..he landed at Chrysler in '36.

[Jim Brierley]

All Model A, B, C and early V8 cranks are forged, not cast.

[johnneilson]

Hicks recommended larger journals, Henry replied that "the crank should be left limber enough to follow the bores in the block".
That is sound engineering right there.

J

[Jack Shaft]

His house his marbles..he would shutdown entire processes at the Rouge for cleaning,production be damned.My favorite was wanting to keep building the T,sales be damned..

Reckon he was set in his ways,and rich enough to get away with it..in the end its not about money,its about power..

[JOHNCL]

I opened up my newly acquired October 1928 Model A and found several things. it does have the beaver tail crankshaft. it does have I-beam connecting rods, however. and those are using the 21/32" nuts on the big end. I found about 1/4" of sludge on the floor of the pan and the dipper tray was very clean. The oil pump screen had almost no debris clogging it. The valve spring chamber had thick sludge in it to the level of the oil gravity ports to the mains and the oil return tube is the high type. I think that this indicates the Ford designers intended this to be a catch basin for debris; it worked. :-) I am surprised that my assorted books provided almost no information on the gravity system. As for pressurizing the mains, much is written and illustrated.

[rotorwrench]

Originally Posted by Jack Shaft

Hicks and others pushed for a larger journal,Ford countered that flywheel mass was sufficient to deal with it..Ford won...With the 'new and redesigned four for 1932'. Engineering got their wish..Hicks was already on the skids by then, Ford found him to be impetuous..he landed at Chrysler in '36.

Harold Hicks was a college boy & had worked for the Aviation department for a long time and Larry Sheldrick was not as well trained in those arts so there was likely some professional jealousy there. Henry Ford favored guys that had the school of hard knocks education likely due to his own similar education.

Harold Hicks was laid off in 1932 with a lot of other workers due to the hard times. Sheldrick stayed on more so because he ran the department and Hicks didn't. Harold was one to speak up with improvement ideas but some of his "improvements"could ruffle the feathers of either Henry Ford or Larry Sheldrick depending on who was more affected by the idea. He reflected on that in page 165 of his reminiscence on the Henry Ford site.