Description
This is a Hard Exhaust Valve Seat for Austin Healey BN4 to BJ8 that uses the 1.555 size exhaust valve. Valve seat inserts are a very important component of the valve train in your Austin Healey engine. These hardened valve seats are the interface between the exhaust valve and the cylinder head and the Valve and valve seat work together to seal off the combustion chamber from the exhaust gases trying to escape. The valve seat also keeps the valve from having direct contact with the cylinder head and absorbs part of the combustion heat which is transferred to the valve by passing it on to the cylinder head. Originally the Austin Healey engine was designed to run on leaded fuel (gasoline) which cushioned the blow of the slamming shut of the exhaust valve. Now since unleaded fuel is your only option, hardened valve seats must be installed to stop the tulip wear of the valve face or the destruction of the cylinder head. During a valve grind your cylinder head should be inspected to insure the valve seal surface is in good shape to keep you Austin Healey BN4 to BJ8 running great.
