Tag Archives: head
What is a Long Block and How Is It Best Used
Repairing an engine by a complete overhaul is a popular way of maintaining tractor engines, and ensuring continuous problem free operation of heavy duty machines. However, the overhaul process can take a minimum of five (5) days if all of the parts are readily available for the overhaul, and typically approximately ten (10) days for the complete overhaul to be completed, with the additional time to procure the parts needed for the overhaul.
Depending on what needs to be repaired on the old engine, a complete block assembly engine, or a long block as it is sometimes called, can be faster repair job for a tractor engine that requires a new block and a cylinder head.
The short block comprises of the cylinder block and the crankcase connected by a connecting rod and precision heavy duty welding. The long block is the next level in engine repair, as compared to the short block. The long block has additional components that make repairs less tedious.
The most significant addition that makes up the long block is the cylinder head. This is bolted to the top of the cylinder block by head bolts and sealed with a head gasket. Depending on the engine model and manufacturing company, the cylinder head can contain a section of the combustion chamber. All will have the intake valves, exhaust vales, valve springs, valve keepers, and the rocker arm assembly. The rocker arm assembly comprises of the rocker arm shaft, tappets, push rods, and the rocker arms. The camshaft assembly in the crankcase moves the push rods which mechanically operates the rocker arm assembly.
Both the long block and the short block will have the front gear train, with pulleys and chains. However, the long block will have the front plate, which is a protective covering for the gear train components.
In some models, the rear seal housing with the seal is provided. For example, the 6081 John Deere engine long block, this housing is provided as a part of the complete engine assembly.
The oil pump and oil pump accessories are another pertinent addition to the long block assembly. The exact location of the oil pump varies by engine type and manufacturer, however, a large percentage of oil pumps are fitted in the lower section of the crankcase, with an oil filler tube extending downwards into the area where the oil pan will be located. At the bottom of this filler tube, is fitted an oil strainer.
The long block would have been fitted internally with many gaskets, including the front gear train gasket, the oil pump gasket, the head gasket, and a few others. However, since there will be many engine accessories to be added to the external parts of the engine, a complete gasket kit is normally shipped with the engine assembly. This will include gaskets for the exhaust and intake manifolds, water pump, fuel pump and fuel transfer pumps.
For completely remanufactured engine assemblies that were rebuilt to OEM specifications, all internal components used in the rebuilt process will be new components, with the exception of the blocks, cylinder head, and crankshaft which are typically rebuilt to OEM specifications and reused.