Valve engine problem Brisbane - WORN OUT
Valve stem wear is a normal occurrence after many thousands of miles are clocked up on an engine. The premature appearance of severe stem wear and guide wear is abnormal. There are many causes of this condition and care must be taken to ensure the cause is eliminated at the time of guide and valve replacement. Insufficient guide clearance after a cylinder head overhaul can cause the valve stem to momentarily seize up and subsequently create aggressive wear in the guide or stem. Bad guide to seat alignment will accelerate stem and guide wear as extra side thrust is placed on the head of the valve as it attempts to square up onto the seat. Incorrect rocker arm geometry will exert abnormal side thrust on the tip of the valve causing abnormal stem and guide wear. Lack of stem lubrication is another cause and should be checked upon reassembly. There are many different methods used to ensure oil finds its way to the valve guides. Most times a small oil drilling or spray bar is used to lubricate the rocker assembly and valve guides. Check operation of oil system after assembly. Dry assembly and dry start can cause the initial damage that accelerates the stem wear. Use good quality, clean engine oil to saturate the guide and stems upon assembly. Not polishing valve stems after unprotected bead blasting of valves will cause accelerated guide and stem wear. 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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RACQ Approved Automotive Repairer
Valve engine problem Brisbane - WORN
OUT
Valve stem wear is a normal occurrence after many thousands of miles are clocked up on an engine. The premature appearance of severe stem wear and guide wear is abnormal. There are many causes of this condition and care must be taken to ensure the cause is eliminated at the time of guide and valve replacement. Insufficient guide clearance after a cylinder head overhaul can cause the valve stem to momentarily seize up and subsequently create aggressive wear in the guide or stem. Bad guide to seat alignment will accelerate stem and guide wear as extra side thrust is placed on the head of the valve as it attempts to square up onto the seat. Incorrect rocker arm geometry will exert abnormal side thrust on the tip of the valve causing abnormal stem and guide wear. Lack of stem lubrication is another cause and should be checked upon reassembly. There are many different methods used to ensure oil finds its way to the valve guides. Most times a small oil drilling or spray bar is used to lubricate the rocker assembly and valve guides. Check operation of oil system after assembly. Dry assembly and dry start can cause the initial damage that accelerates the stem wear. Use good quality, clean engine oil to saturate the guide and stems upon assembly. Not polishing valve stems after unprotected bead blasting of valves will cause accelerated guide and stem wear. 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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