The FEL-PRO PermaTorque/Blue Stripe
®
and PermaTorque/Printoseal
®
cylinder head
gaskets do not need retorquing. They combine the proper amount of compressibility
with torque-retaining materials for a long-lasting seal.
FEL-PRO cylinder head gaskets use a variety of gasket constructions and materials,
carefully chosen by our engineers for each specific engine application and thoroughly
tested. All FEL-PRO PermaTorque cylinder head gaskets consist of four basic parts –
the core, the facing material, the coating, and the armor. Other special enhancements,
such as elastomeric sealing beads, may be added to improve sealing even further.
Coatings can be either PTFE rubber or silicone-based. They help seal minor surface
imperfections, resist sticking, and help the gasket resist the shearing action that occurs
in bi-metal engines. Aluminum cylinder heads and cast iron engine blocks expand
and contract at different rates during engine heating/cooling cycles. The anti-friction
coatings used on PermaTorque head gaskets allow both the head and block to “slip”
over the gasket surface and still maintain a good seal.
Formed metal armors are added to protect the gasket body at cylinder openings.
Each armor is precision stamped and then formed to the gasket body. Engineers specify
different armor materials, ranging from tinplate to stainless steel, depending on the
specific engine application.
The most common PermaTorque/Blue Stripe design uses a solid steel core with rubber/
fiber facing material. The solid steel core minimizes torque loss, while the soft facing
conforms to seal minor surface irregularities.
rubber/fiber
facing material
tinplate or
stainless steel
armor
anti-friction coating
solid steel core
eliminates retorquing
FEL-PRO
®
PermaTorque
®
CYLINDER HEAD GASKETS
core facing coating armor reliability
PermaTorque/Blue Stripe Solid Core Design
PermaTorque/Blue Stripe Clinched Core Design
PermaTorque/Printoseal Solid Core Design
Another popular PermaTorque/Blue Stripe design uses a clinched steel core construction,
combined with either expanded graphite or dense composite facing material. The “S” shaped
protrusions of the clinched core allow more uniform loading of the gasket than competitive
designs. High-density expanded graphite is used for high-temperature applications where
required. The composite facing material uses rubber/fiber design that is densified during
the production process. This material is dense enough to help maintain torque, yet
compressible enough to conform to minor surface irregularities.
When the engine requires additional sealability, Printoseal
®
elastomeric sealing beads
are applied around critical openings such as coolant and oil ports, to prevent oil and
coolant leakage. On many current lightweight engines, the beads also help seal
aluminum castings that have uneven clamping force across the gasket surface.
clinched steel core
dense composite
facing material
eliminates
retorquing
tinplate or
stainless steel
armor
anti-friction coating
tinplate or
stainless steel
armor
Printoseal
®
elastomeric
sealing bead
rubber/fiber
facing material
solid steel core
eliminates retorquing
FEL-PRO
®
PermaTorque
®
CYLINDER HEAD GASKETS
