Spark Plug Thread Repair
Professional thread repair solutions for damaged spark plug threads in aluminum and cast iron cylinder heads.
Why Spark Plug Threads Fail
Over-Torquing
Excessive tightening force strips threads in soft aluminum heads.
Cross-Threading
Improper installation damages thread form beyond repair.
Thermal Cycling
Repeated heating and cooling weakens aluminum threads over time.
Corrosion
Carbon buildup and corrosion deteriorate thread integrity.
Seized Threads
Seized spark plugs damage threads during removal attempts.
Professional Repair Solution
Time-Sert and Big-Sert spark plug thread repair kits provide a permanent solution without removing the cylinder head. The solid steel insert is stronger than the original aluminum thread.
Installation takes 30-60 minutes per spark plug hole and can be performed with the engine in the vehicle.
Available Spark Plug Kits
Time-Sert Kits
Standard spark plug thread repair for normal to moderate damage.
- M10 x 1.0 (10mm spark plugs)
- M12 x 1.25 (12mm spark plugs)
- M14 x 1.25 (14mm spark plugs)
- M18 x 1.5 (18mm spark plugs)
Big-Sert Kits
Oversize repair for severely damaged or previously failed repairs.
- M14 x 1.25 oversize (14mm spark plugs)
- M18 x 1.5 oversize (18mm spark plugs)
- Larger diameter for maximum strength
- Ideal when standard repair won't fit
Installation Overview
Remove Plug
Remove damaged spark plug carefully
Tap hole
Use step tap provided to cut thread
Counterbore
Create recessed seat for insert
Install
Install insert using insert driver
Lock
Lock insert in place using insert driver
Common Applications
Ford Triton Engines
4.6L, 5.4L, and 6.8L V8/V10 engines are notorious for spark plug thread issues. Time-Sert provides permanent repair.
GM LS Engines
Aluminum LS1, LS2, LS3, and other LS-series heads benefit from Time-Sert repair when threads are damaged.
Import Aluminum Heads
Honda, Toyota, Nissan, and other import vehicles with aluminum cylinder heads.
Performance Engines
High-performance and racing engines where thread strength is critical for reliable operation.
Marine Engines
Boat engines with aluminum heads that have suffered corrosion or thread damage.
Motorcycle Engines
Sport bikes and cruisers with aluminum cylinder heads requiring thread repair.
Need Help Selecting the Right Kit?
Not sure whether you need Time-Sert or Big-Sert? Our technical team can help you choose the correct kit for your specific application.