Early on in discussions of this artifact, I suggested it was part of the engine oiling system, which was largely external. That still doesn't seem to explain explosive damage. If I had my druthers, I'd take it to Paris and hold it up next to the engine on display looking for a match to some part there.

Were the cylinders cast with water jackets, or were the water jackets made separately and added around the cylinders? It appears the engine had individual cylinders rather than a cylinder block. The cylinders might not even be castings.

Don W.

It was confusion over time zones that led the Itascans to think Amelia wasn't sticking to her radio schedule. She was, but in a different time zone from theirs.

Don W

I think that if the artifact is indeed an internal component of the engine then this changes the search in a meaningful way. How? There is likely no large chunk of metal lying around on the bottom of the pond to be identified by magnetometer (i.e., the engine came apart in a catastrophic way). Instead, there may be several smaller bits widely distributed that each need to be investigated. Although having a single large chunk of metal is likely easier to find in the broad sense, having multiple smaller bits (any one of which would possibly confirm the crash) actually raises the odds.

Don....

----The fuel system modifications during the crash repair, I got from the book Missing by Nesbit, P16 (‘equalising lines added’).

Secondary source.  If not cited to a primary source it's not reliable.

----The weather forecast: according to Elgen Long, P185, ‘...True had sent the message the evening before’.

That's right.  The evening before the morning of July 1 was the evening of June 30.

In the archivehttps://tighar.org/Projects/Earhart/Archives/Research/JacobsonDatabase/RADIOMES/MSG7.PDF P79, the message has a date stamp 193706302250

You're right.  I was looking at an earlier forecast.
 

----The position report at 2:18pm (4:18GMT): Chater said ‘...the plane was called and asked to repeat the position, but we still could not get it’. That is due to the poor radio reception, so there is a missing position.

The full quote is "The Lae Operator heard the following on 6210 KC –“HEIGHT 7000 FEET SPEED 140 KNOTS” and some remark concerning “LAE” then “EVERYTHING OKAY”. The plane was called and asked to repeat position but we still could not get it."  She made "some remark concerning Lae."  Chater is assuming she gave a position, but the best Noonan could do without a landmark was an estimated distance from Lae. 
 

 You cannot have it both ways. If the position 150.0E 7.3S is accurate, then it is a dead reckoning position and the time is wrong. If it is not correct, then there is a missing position at 05:19GMT which we have to fill-in. That is why you invented position 157.0E 7.3S and I invented Position 156.

 

You're assuming the time is wrong.  I'm assuming that 157E 7.3S was misunderstood as 150E 7.3S. I think my assumption is more reasonable.

----Sunrise at Howland was 05:45 Howland Local Time. That is specific to the location of Howland and has nothing to do with time zones.

It has everything to do with time zones. Sunrise at Howland was 05:45 Howland Local Time according to present day time zone conventions.

IIRC, Howland was on Hawaii standard time, and the Itasca was off Hawaii time by 1 hour.

Hi Ric

----87 octane fuel agreed. You are 2 for 7

----The fuel system modifications during the crash repair, I got from the book Missing by Nesbit, P16 (‘equalising lines added’).

----The weather forecast: according to Elgen Long, P185, ‘...True had sent the message the evening before’.

     In the archivehttps://tighar.org/Projects/Earhart/Archives/Research/JacobsonDatabase/RADIOMES/MSG7.PDF P79, the message has a date stamp 193706302250

----The position report at 2:18pm (4:18GMT): Chater said ‘...the plane was called and asked to repeat the position, but we still could not get it’. That is due to the poor radio reception, so there is a missing position.

 You cannot have it both ways. If the position 150.0E 7.3S is accurate, then it is a dead reckoning position and the time is wrong. If it is not correct, then there is a missing position at 05:19GMT which we have to fill-in. That is why you invented position 157.0E 7.3S and I invented Position 156.

----Sunrise at Howland was 05:45 Howland Local Time. That is specific to the location of Howland and has nothing to do with time zones. It is 06:15 Itasca Local Time when Itasca is in the vicinity and is 07:15 Hawaii Local Time according to whatever convention is in use.

I thought it looked a bit like a cylinder wall, but i could not come up with a very convincing theory of how it would blow up like that. It's just not a common kind of failure. This was a proven design and engineers knew how to build engines that would resist pressure. I came up with two rather weak ideas: 1) that the engine was forcibly stopped at the exact moment of ignition, so the full force of combustion had nowhere to go but through the cylinder wall; 2) that the overheated engine hit the cold water with enough temperature differential to cause the metal to crack (why you don't add cold water to a hot cast iron engine, or put your hot cast iron pans in cold water).

Has anyone tried taking this bit to the actual engine on display to see if it matches anyplace?

As for the type of metal, 12L14 appears to be the current American designation for a very old kind of steel, which has had other names in other times and places. In England it is classed as Bright Mild Steel, which is a common variety for machining. Knowing when it started to be called 12L14 may not answer when it was first made.

Don W.

This Car and Driver article (June 3 2023) has many details about and photos of the restoration process and its results:
https://www.caranddriver.com/features/a44028908/amelia-earhart-cord/

It's always seemed more like part of an oil sump or some such to me.

My earliest idea when we first found it was that it might be part of the oil tank.  There was a 60 gallon oil tank immediately behind the engine, as shown in this photo of the aircraft under construction.  We don't know whether the tank was aluminum or steel, but the photo looks like either unpainted aluminum or painted steel.

It's always seemed more like part of an oil sump or some such to me.