Cylinder Sleeve Flange Failures May Go Unnoticed
Cylinder sleeve flange failures may go unnoticed if the sleeve body stays in position, but if it is pulled down the cylinder, the result can be catastrophic. Cylinder sleeves are usually made from centrifugally cast iron, which makes for good wear resistance, but they can be fractured if dropped or crushed. This usually appears as a crack running down the length of the liner. – Cracks which follow the underside of the flange are caused when fitting the sleeve to the cylinder block, or when installing the cylinder head. With care, these cracks can be avoided. Cracks that start under a sleeve flange are caused by twisting of the flange and the sleeve being pulled apart. The following are causes of and ways to avoid this type of failure. When installing a sleeve: • If a press is used to push the sleeve into position, a rigid plate must be placed between the press and the sleeve. If the plate bows, a bursting stress will be imposed on the cylinder sleeve. • Care must be taken to ensure that excessive pressure is not used. This could shear off part of the sleeve flange once it has been pushed fully home into its recess. • Be certain that the cylinder block counter bore is even, uniform in depth and parallel to the top surface of the block. • Be certain the counter bore seat is not worn at the inner edge. If worn, it will cause the seat to tilt downward and possibly crack. • Be certain there is not an unequal protrusion of flange height in relation to the top of the block. – When installing cylinder heads: • Always use the correct torquing sequence. An improper sequence can result in failure. • Do not tighten head bolts more than what is recommended. Excessive tightening can result in failure. If lubrication is used to assist fitting the sleeve, the cylinder block should be lubricated, but not the sleeve. Otherwise, the lubricant will be scraped off the sleeve as it is pushed home. The lubricant will accumulate in the block recess and prevent the flange from seating. In time, the lubricant will dissipate and leave the flange unsupported and vulnerable to fracture. When correctly installed, a cylinder sleeve becomes an integral part of the cylinder block and can only be removed intentionally or by a severe engine mal- function.
Scott York
Advantage Engine Parts
Lynn, IN
September, 2013
