Dumb question - Forged vs Cast
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Post Fiend
Joined: Sep 2004
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From: Near Fresno, California
Dumb question - Forged vs Cast
What is the difference between a forged part and a cast part? What is "forged" and what is "cast"
On a cast iron block, is the entire engine, including the cylinders, all the same material, or are steel sleeves inserted into a cast iron block at the foundry?
What is the process when you have an engine "sleeved"?
On a cast iron block, is the entire engine, including the cylinders, all the same material, or are steel sleeves inserted into a cast iron block at the foundry?
What is the process when you have an engine "sleeved"?
Needsmorecoffee.
Joined: Oct 2004
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From: CT
Forged steel is a process where a chuck of steel is heated and pressed into it's shape. Cast iron is casted where the molten iron is heated and poured into the mold or form. Iron cranks have a parting line running down them and steel cranks none. The iron blocks are just that iron. Sleeves are pressed into a cyl bore that is beyond it's limits and are steel in most cases. The only factory sleeve i've seen was in a NOS 428 service block I had and was installed in one of the lifter holes. The process for sleeving a cyl is to overbore the cyl and press the sleeve into it and machine to finish. It's a little more involved but that's the basic idea. G.
Post Fiend
Joined: Jun 2002
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From: Atlanta GA
To add a bit more.
On many forged parts the steel is smacked with tens of tons of steel to form it into shape. Some cases, 100+ tons of steel. There is hot forged and cold forged too. The line running down a cast part is from the seam of the mold halves.
On many forged parts the steel is smacked with tens of tons of steel to form it into shape. Some cases, 100+ tons of steel. There is hot forged and cold forged too. The line running down a cast part is from the seam of the mold halves.
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Post Fiend
Joined: Sep 2004
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From: Near Fresno, California
Thanks, that helps.
But tell me, if all FEs come from the same mold, what is the differance in the cylinder wall thickness? I mean, if you can machine the same engine casting to a 390 or a 428 at the foundry, how come the walls are too thin to do it later?
But tell me, if all FEs come from the same mold, what is the differance in the cylinder wall thickness? I mean, if you can machine the same engine casting to a 390 or a 428 at the foundry, how come the walls are too thin to do it later?
Needsmorecoffee.
Joined: Oct 2004
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From: CT
Well not all FE's come from the same mold. There are differences like the 428,427 etc... where block's are different. There was a certain set of cores for water jackets and cly walls which determined which block got what. But as supply and demand goes you use what you have. If ford was running low on 390 blocks it was not uncommon for them to subsitute a 428 block bored to 390 specs etc.... I'm sure somethings were misteaks or casting flukes. In fact I have one myself. A 63 406 block with two different cyl wall cast in. The right side has the std 406/428 wall thickness and the left side 427 wall thickness. The block was cast third shift and figure the core setter dropped the last set of 406 cores and in turn grabbed a 427 core to finish setting the mold. So there were determined cores to certain block castings just not always followed practice it seems. That's why you will see the same casting numbers for some blocks like the 390 and 428. Just different wall thickness cast in them to save time and money. G.
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more trivia...the block is not iron, it is cast iron, which is kind of a misleading name. Steel is iron with carbon as its alloying element. Steel has up to 2 percent carbon, but cast iron is iron with more than 2 percent carbon. Its very hard but brittle and with that much carbon its almost impossible to weld. Casting verses forging... Castings have large grains which gives the cast material certain properties. A forging is usually much stronger than a casting becasue the grains are refined during the forging processes making them smaller and stronger.
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