4JJ1 8 - 97355 - 9 - 708 Diesel Engine Cylinder Head For Zx130-5a
Used
Specification
| Type: Engine cylinder head | Model Number: 4JJ1 |
| Application: Excavator | Part number: 8 - 97355 - 9 - 708 |
| Type: Electric injection | valve: 16 valve |
| Car Make: Hitachi | Number of Cylinders: 4 |
Description
What is a cylinder head?
Cylinder head, A part of an internal combustion engine, usually
made as a removable piece, that closes one end of the engine's
cylinders. In an internal combustion engine, the cylinder head sits
above the cylinders on top of the cylinder block.
Function
The purpose of the cylinder head is to provide a place for
combustion of the fuel/air mixture and to give the cylinder more
heat conductivity for adequate cooling. The fuel/air mixture is
ignited by the spark in the combustion chamber and commences
burning as the piston travels toward top dead center on the
compression stroke. The ignited charge is rapidly expanding at this
time, and pressure is increasing so that, as the piston travels
through the top dead center position, it is driven downward on the
power stroke. The intake and exhaust valve ports are located in the
cylinder head along with the spark plugs and the intake and exhaust
valve actuating mechanisms.
Material of parts of cylinder head
After the cylinder head is cast, the spark plug bushings, valve
guides, rocker arm bushings, and valve seats are installed in the
cylinder head. Spark plug openings may be fitted with bronze or
steel bushings that are shrunk and screwed into the openings.
Stainless steel Heli-Coil spark plug inserts are used in many
engines currently manufactured. Bronze or steel valve guides are
usually shrunk or screwed into drilled openings in the cylinder
head to provide guides for the valve stems. These are generally
located at an angle to the center line of the cylinder. The valve
seats are circular rings of hardened metal that protect the
relatively soft metal of the cylinder head from the hammering
action of the valves and from the exhaust gases.
What are the causes of bad cylinder heads?
First of all chamber Cracks. One of the most common failure points
for any cylinder head -- particularly those that use multiple
intake or exhaust valves lay between the valves themselves.Such
as:1. Head Cracking 2. Warped Heads 3. Worn Valve Guides
