Do "Forged" Engine Blocks exist?

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Just wondering?

Another dilemna related to the above question. Even in a cast metal peice such as lets just say a cast iron block how are they able to cast the internal oil and coolant galleries?

Are these machined? I can not conceptualize how any standard cast can form internal cavities for such.

And if this coolant and lubricant passageways are machined, then perhaps a forged block is possible in principal?

Sorry to many assumption here but it is question that i have been meaning to post.
 
There are methods to cast forms such as engine blocks with internal passages for coolant, oil, etc. If memory serves me right, I think one of the processes is called the "lost wax" method, where the pattern is built-up of a meltable material, the mold is formed using sand around the meltable material, then the mold is heated to remove the pattern leaving an internal cavity. I'm sure there are more sophisticated versions of this process used in engine manufacture.

Machining of the engine block would be kept to a minimum. Machining = cost. Wherever possible, I'm sure they design the casting to be used "as molded".

I'm not sure I can answer the "forged engine block" question. I don't think the forging process lends itself well to intricate 3-dimensional items. While it might be possible on some theoretical level, or to forge parts of the engine block, I suspect that forging an entire block would not be practicle and / or be cost prohibitive. (disclamer, I'm not the expert here)
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[ April 22, 2003, 10:45 PM: Message edited by: Rick in PA ]
 
Can't help much, but I found this from a paper describing Toyota's 1ZZ-FE engine:

"The cylinder block is a high-pressure aluminum die casting of an open-deck construction with thin cast-in iron liners. It is 32% lighter than the previous cast iron block and offers greater production efficiency. The water pump swirl chamber, the inlet housing and bypass passage lead are integrated into the high pressure aluminum die-cast cylinder block, contributing to a compact body. To counteract casting cavities which can occur in the thick wall portions produced from body integration and at the crankshaft main journals, the production procedure uses a pin to squeeze these thicker portions."
 
I have never heard of a forged block. That would seem to be expensive and totally unnecessary.

The major parts of engines that can be forged are crankshafts and cams etc. Items where there is stress associated with the operation. Lots of the early 60's GM high performance engines used forged cranksafts.

Blocks are cast using sand molds and I think GM and probably others use what it called "Lost Foam Method". Sand casting was used for many years. Hot molten iron is poured in a mold and sand is used to represent the areas to be open of iron.

To see how its done, you have have to the River Rouge Ford foundry in Detriot.

[ April 23, 2003, 08:36 AM: Message edited by: Mike ]
 
Engine blocks have been made from some exotic materials including reinforced plastics and ceramic. The ceramic material is especially promising because it allows much higher engine temperatures for better efficiency.
 
Now that this post was brought up. If money wasn't an issue. Would it not be a bullet proof idea to create a complete engine out of Titanium. eg Head, Block, and all internals?
 
Traditionally the internal passages were represented with a sand and water-based adhesive core set in the major mold (also a sand and water-adhesive mold). Several passages between the outer major mold and inner mold were approriately placed. After the molten metal (iron and later aluminum) was poured in the mold casing and allowed to solidify, the major mold casing was broken and the outer mold broken/rinsed away. The passages alluded to earlier are then broken away and the resultant "holes" in the block are then rinsed with high pressure water to break up and flush the inner sand mold out of the block or head casting. The resulting cavities would be the various cooling and oil gallaries. The holes left over from the previously alluded to connecting passages are then capped with "core" plugs. In sub-zero conditions if the coolant freezes, with any luck the core plugs will pop out before the block or head cracks from the pressure of ice (water expands as it freezes). Hence the misnomer, "freeze plug", came into common usage. As mentioned previously, another casting method using wax has been in use for centuries for casting intricate shapes, too. It involves carving the shape in wax and placing the wax model in a casing and pouring plaster or other heat tolerant material around it in the case. Once set up, molten metal is poured over the wax, which instantly burns/melts away allowing the metal to form the same shape in the resulting cavity. The outer casing is broken away exposing a newly cast metal item identical to the original wax core. Great for jewelry, and this is how rings are made, but the wax was permanently lost in the process. G.M. looked at lost-wax casting and developed a method whereby styrofoam cores were used instead of wax. The weight savings were considerable when considering the weight of a cylinder head-sized chunk of parrafin wax. In the case of something like a cylinder head or block, the internal passages would need to be sand-filled as in conventional casting described above located between bonded halves of styrofoam since the internal passage core would need to be heat tolerant during the casting process. It's easy to recognize a lost foam casting. The "cells" are clearly visible on the surface of the metal just as they were on the original styrofoam core. Smooth castings formed in high temperature steel dies or lost foam castings require minimal machining, but sand cast aluminum blocks and heads are still made, too.
 
In aerospace, we use a lot of titanium and its alloys, which has the strength of steel and is slightly heavier than aluminum.

Titanium is very expensive and difficult to machine. It is also difficult to lubricate. A whole new set of oils would have to formulated to work with Titanium blocks.

Cast Steel or iron seems to have the right wear properties since the grain directions and orientations lend themselves to linear bearing operation, which is a piston ring/liner system.

[ April 25, 2003, 11:49 PM: Message edited by: MolaKule ]
 
quote:

Originally posted by outrun:
Just wondering?

Another dilemna related to the above question. Even in a cast metal peice such as lets just say a cast iron block how are they able to cast the internal oil and coolant galleries?

Are these machined? I can not conceptualize how any standard cast can form internal cavities for such.

And if this coolant and lubricant passageways are machined, then perhaps a forged block is possible in principal?

Sorry to many assumption here but it is question that i have been meaning to post.


Interesting, I don't know if such a animal has been done. If it has my guess would be in AA nitro drag racing. 5000 plus horse power out of 500 C.I.D. One thing I do know is that a cast part, sand cast or investment cast is much more stable on machined surfaces down the road. Important for a home for the crank and heads at 100,000 miles. Cast is much easier to machine accurately. The bigger the size of the part the better a cast part looks. Forged parts are stronger at the same thickness with the same material. Forged parts have a grain structure flowing one direction. A cast part the molecules are in a random order. This is the reason a cast part is much more stable. The cost of forging a part is many many times greater than a cast part. I know of one titanium forging in the aerospace industry that cost over 125 grand before it is machined. Later
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