4JJ1 Diesel Used Engine Cylinder Head For Excavator Zx130-5a 8-97355- 9-708

4JJ1 8 - 97355 - 9 - 708 Diesel Engine Cylinder Head For Zx130-5a Used

Specification

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