Valve engine problem Brisbane - HOLE IN
This condition is not as common as other valve problems. It is more common on stellite or hard faced valves. The main cause again is excessive temperatures caused by poor timing, weak valve spring tension, poor seat contact, overloading or fuel mixtures. The reason the valve ends up with a hole in it just below the valve face is that the material is more resilient on the hardened face area than the body of the valve. The thickness of the valve at this point gives an indication of the extreme temperatures required to do this to a valve. When this occurs it is very important to check the stability and security of valve seat inserts. Quite often the valve seat will have lost it's .006" interference fit and may come loose in service causing a major blow up. A simple test used by engine reconditioners is to tap the inserts with the side of a solid punch, listening for the sound difference. A loose insert looses the rather sharp contact noise and produces a rather different dull thud. The same causes as for a cracked/burnt valve can be examined for this problem. 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
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Valve engine problem Brisbane - HOLE
IN
This condition is not as common as other valve problems. It is more common on stellite or hard faced valves. The main cause again is excessive temperatures caused by poor timing, weak valve spring tension, poor seat contact, overloading or fuel mixtures. The reason the valve ends up with a hole in it just below the valve face is that the material is more resilient on the hardened face area than the body of the valve. The thickness of the valve at this point gives an indication of the extreme temperatures required to do this to a valve. When this occurs it is very important to check the stability and security of valve seat inserts. Quite often the valve seat will have lost it's .006" interference fit and may come loose in service causing a major blow up. A simple test used by engine reconditioners is to tap the inserts with the side of a solid punch, listening for the sound difference. A loose insert looses the rather sharp contact noise and produces a rather different dull thud. The same causes as for a cracked/burnt valve can be examined for this problem. 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
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