Head engine problem Brisbane -

BLOWN

The normal combustion temperature reaches around 2000 to 2500 degrees Celsius. If an engine is running under stress caused by overloading, lean mixtures, incorrect injector timing, incorrect ignition timing, or overheating, combustion temperature can rise to anywhere around 3000 degrees C. At these temperatures the combustion will melt and burn any sharp edge that protrudes into its path. Once the hot spot is established the extra heat generated by the molten metal adds to the combustion temperature, increases detonation and aggressively continues to burn away the cylinder head, sealing ring of the head gasket, piston crown or edge of the cylinder wall. While this is happening the performance of the engine will be noticeably laboured, accompanied by audible pinging and knocking. The coolant temperature will be high and the oil pressure considerably lower than normal. A few good reasons to shut off the ignition but most drivers prefer to squeeze the last few yards out of the engine. When the engine is continually driven after the head gasket has failed between cylinders, the combustion cross firing between the two cylinders burns out a groove in the head and block face. The head will often require building up in the burnt area before surface grinding. The appearance of the affected area is as if an oxy torch was used to create the gouge. Many fine heat surface cracks are commonly found around the effected area and will require removal with a burr before welding can be carried out. As the block position can also be damaged it must be repaired for the gasket to correctly seal. Another major cause of gasket failure is the modern engine tends to suffer from soft heads. This condition does not allow the maintenance of the correct clamping pressure on the gasket. Over a fairly short period the head bolts become loose and the clamping pressure is reduced to where the gasket fails. Soft alloy heads should not be re-used. Always check alloy heads for hardness. Disclaimer Agreement : Every care has been taken in writing this information and procedures, but no responsibility can be excepted for errors, omissions or misuse of this information and procedures. The information available on this site is for your instruction only and cannot be copied for sale, © copyright 2001 UMR Engines