Inliners International Forums General Discussion Engines Hardened Valve Seat Inserts and unleaded fuel . . .

with the intended normal use of your motor, i can see no reason to change to hardened seats. to me it is more of an issue with heat and long term high speed operation. for instance 292 were used in ag equipment such as combines. this was a heavy sustained load and at a reasonably high rpm 2000-2400. this would be a case for hardened seats on the exhausts. atleast to me. tom