Design Engineering Dei Spark Plug Boot Heat Sleeve

Protect-A-Boot Heat Sleeves from Design Engineering (DEI)

Spark plug boots and wires that sit close to exhaust headers take a lot of abuse. Radiant heat hardens the rubber and silicone, cracks the insulation, and can eventually cause misfires. Design Engineering, Inc. (DEI) built its Protect-A-Boot line to address this problem. DEI is an Ohio-based specialist in heat and sound control, founded in 1995 to tackle underhood, power-robbing heat in racing and performance applications. Its spark plug boot heat sleeves are a direct product of that focus.

How Protect-A-Boot Sleeves Are Built

Protect-A-Boots are made from a tightly woven, high-temperature-resistant glass fiber material treated with a proprietary coating. The sleeves use double-wall construction for added durability and are rated to withstand direct, continuous heat up to 1200°F. They are also non-flammable and resist water and chemicals, which matters in an engine bay exposed to oil, coolant, and road spray.

Installation is simple. The sleeves slide over the boot and wire end, and DEI describes the process as taking only seconds. Standard sleeves are universal and fit most straight or angled boots. They also include a reinforcement ring at the base that makes plug removal easier during maintenance.

Sizes and Styles Within the Line

DEI offers Protect-A-Boot sleeves in several formats, so you can match the sleeve to your boot style and header clearance:

• Standard 1 in. I.D. x 6 in. sleeves: The core Protect-A-Boot design, sold in packs of 2 or sets of 8 for a full V8. Colors include silver, black, blue, and yellow.
• Protect-A-Boot XL: An extra-long 8 in. version for boots that need more coverage along the wire.
• Ringless sleeves: A 1.25 in. I.D. design with pliable construction. It suits extreme-angle, oversized, or rigid boots, such as ceramic ignition wire ends and thicker aftermarket boots from performance ignition makers.

Pairing Sleeves with Header Protection

Where wires touch or sit very close to a header tube, DEI recommends adding header wrap in the problem area alongside the sleeves. This lowers the radiant heat load at the source while the sleeves protect the boots and wire ends. DEI's wider catalog of heat wrap, heat shields, and sleeving products makes this combined approach straightforward.

Shopping Considerations

• Boot diameter: Measure your boot. Use the 1 in. sleeves for typical boots and the 1.25 in. ringless style for oversized or rigid ends.
• Length: Choose 6 in. or 8 in. depending on how much of the boot and wire sits in the heat zone.
• Quantity: Count your cylinders and decide whether a 2-pack or an 8-pack is the better fit.
• Header proximity: Tight, hot routing is where a sleeve earns its keep.

To see everything the manufacturer offers, visit the Design Engineering Dei brand page. To compare other options for protecting ignition components, browse the full Spark Plug Boot Heat Sleeve category.