Expansion Plugs 11/16 25pk Deep Cup Style

The Expansion Plugs 11/16 25pk Deep Cup Style from Pioneer are essential fasteners for engine block restoration and repair work. These plugs fill freeze holes and core holes drilled during casting, which can weaken the engine block and lead to coolant leakage if not sealed. They are designed for use by both professional mechanics and DIY enthusiasts engaged in engine rebuilding or restoration projects.

With a diameter of 11/16 inches, these plugs match common cast-iron block hole patterns found in various domestic and import engines. The deep cup design allows for effective sealing, as the inverted cup shape engages the hole wall under pressure, creating a secure fit. Installation is straightforward: chill the plug, insert it into the hole, and strike the center with a punch or hammer to expand the cup against the bore wall.

Engine builders and DIY enthusiasts will appreciate the 25-pack format, which supports complete block jobs or restorations without the need for multiple orders. This quantity is ideal for high-volume projects, ensuring that you have enough plugs on hand for fleet maintenance or extensive engine work. Compatibility includes popular engine types such as Chevy small-block and big-block configurations.