deafsmogtech
Active Member
- Joined
- May 6, 2009
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this head is from diesel I think. The aluminum cylinder heads use plain bronze or bronze alloy valve seat inserters, where the exhaust valves are pounding the valve seat inserts (referring to closed valves) in high revs and overtimes. That's how the valve seats goes sinking as the end of the valve stems are touching the camshaft side that leave no lashes (clearance) between camshaft lobes and rockers or followers, then create poor sealing and can lead to burnt exhaust valves.