J05E Second Hand Crankshaft For Excavator SK200 - 8 SK250 - 8
134112281
Specification
| Product name: Engine crankshaft | Model Number: J05E |
| Application: Excavator | Part code: 134112281 |
| Staus: Normal | valve: 16 valve |
| Size: Standard | Number of Cylinders: 4 |
| Cooling: Water cooling | Injection: Electric Injection |
Description
A crankshaft contains two or more centrally-located coaxial
cylindrical ("main") journals and one or more offset cylindrical
crankpin or ("conrod") journals.
CRANKSHAFT MANUFACTURING PROCESSES
There is an old argument that a forged crank is superior to a
billet crank because of the allegedly uninterrupted grain flow that
can be obtained in the forging process. That might be true of some
components, but with respect to crankshafts, the argument fails
because of the large dislocations in the material that are
necessary to move the crankpin and counterweight material from the
center of the forging blank to the outer extremes of the part. The
resulting grain structure in the typical V8 crank forging exhibits
similar fractured grain properties to that of a machined billet.
More than one crankshaft manufacturer has told me that there is no
way that a forging from the commonly used steel alloy SAE-4340
(AMS-6414) would survive in one of today's Cup engines.
Some years ago, there was an effort at Cosworth to build a Formula
One crankshaft by welding together various sections, which
comprised the journals, webs and counterweights. The purported
intent was to be better able to create exactly the shape and
section of the various components, thereby reducing MMOI while
achieving the same or better stiffness. While no one was willing to
divulge details about the effort, it is rumored to have been run
once or twice then abandoned due to the high cost and complexity
compared to the measurable benefits.
In certain cases, there are benefits to the use of a built-up
crankshaft. Because of the ‘master-rod’ mechanism necessary for the
implementation of the radial piston engines that powered most
aircraft until well into the second half of the 20th century, a
bolted-together crankshaft configuration was used almost
exclusively. Figure 5 illustrates a typical two-row composite
radial crankshaft and master-rod layout. The loose counterweights
will be addressed later in this article.
