M
Mustangcwo
Guest
Recently, I exploded a head gasket while racing on the 1/8th mile at Qualcomm.
After engine disassembly, it was discovered that my valves were floating and the valve spring pressure, on the GT40 heads, was not sufficient to support a power adder (Vortech V3 10psi). The valve retainers on the inlet valves were wearing quickly and the valves themselves, at the retainer grooves, had become mushroomed from the valve float.
Lesson learned: Stock valve springs start with about 80lbs of holding strength. Around 60K miles, the spring strength is reduced to around 55 - 65lbs. With a power adder, especially supercharging, the springs should be upgraded to dual springs providing 100 - 125lbs of pressure when closed. This will prevent the valves from floating and better seal up your piston chambers.
I will post pictures of the head install, but here is a sneak preview of the upgrades in progress:
Engine teardown:
New (larger) valves on the right, old valves on the left:
Edelbrock Performance 225 aluminum heads:
Old heads GT40 Exhaust Port:
New heads Edelbrock 225 Exhaust Port:
I'll post more pics as they become available.
After engine disassembly, it was discovered that my valves were floating and the valve spring pressure, on the GT40 heads, was not sufficient to support a power adder (Vortech V3 10psi). The valve retainers on the inlet valves were wearing quickly and the valves themselves, at the retainer grooves, had become mushroomed from the valve float.
Lesson learned: Stock valve springs start with about 80lbs of holding strength. Around 60K miles, the spring strength is reduced to around 55 - 65lbs. With a power adder, especially supercharging, the springs should be upgraded to dual springs providing 100 - 125lbs of pressure when closed. This will prevent the valves from floating and better seal up your piston chambers.
I will post pictures of the head install, but here is a sneak preview of the upgrades in progress:
Engine teardown:
New (larger) valves on the right, old valves on the left:
Edelbrock Performance 225 aluminum heads:
Old heads GT40 Exhaust Port:
New heads Edelbrock 225 Exhaust Port:
I'll post more pics as they become available.
