Bigsert Sparkplug

Second Repair M14x1.25 Spark Plug Repair Kits & Inserts

When Standard Sparkplug Repairs Fail

Big-Sert sparkplug repair kits are designed for second repairs when standard Time-Sert sparkplug repairs have failed or when the hole is too large for standard repair methods.

When You Need Big-Sert

  • Failed standard sparkplug thread repairs
  • Oversized holes (commonly up to 16.8mm)
  • Multiple previous repair attempts
  • Severely damaged cylinder head threads

Big-Sert Advantages

  • Repairs holes too large for standard methods
  • Uses original M14x1.25 sparkplug threads
  • Available in both washer and taper seat designs
  • Permanent repair solution

Big-Sert Sparkplug Repair Kits

Washer Seat Insert - Carbon Steel

Kit SizePart NoInsert Length (mm)Insert Part No
M14x1.25 SHORTTS5141S9.40TS51401
M14x1.25 EXTENDEDTS5141E11.00TS51403
5141S & 5141E KITS15.00TS51405
DO NOT INCLUDE INSERTS16.80TS51407
Order separately23.00TS51409

Includes 8 Inserts Total - Assorted Lengths

M14x1.25 Short with inserts
TS5141S-457
Included Washer Inserts
Qty (1) TS51401, Qty (2) TS51407, Qty (1) TS51409
M14x1.25 Extended with inserts
TS5141E-469
Included Taper Inserts
Qty (1) TS51453, Qty (2) TS51457, Qty (1) TS51469

Big-Sert Taper Seat Inserts for Fully Threaded Spark Plugs

Insert Length (mm)Part NoApplication
11.00TS51453Standard
15.70TS51455Standard
16.80TS51457Standard
24.50TS51469Standard
16.80TS5553FORD TRITON
16.80TS5553-8FORD TRITON
24.00TS5554FORD Z-tech

Ford Triple Oversized Solutions

DescriptionPart NoInsert Length (mm)Insert Part NoType
Ford Triple oversizedTS560016.80TS55522Triple Insert Standard
Repairs holes up to .730 inches16.80TS51457
Ford add-onTS558816.80TS55522Triple Insert

Big-Sert® M14x1.25 Spark Plug Inserts - Aluminum

Big-Sert Washer Seat Inserts for Fully Threaded Spark Plugs

Length (mm)Part No
9.40TS51401A
11.00TS51403A
15.00TS51405A
16.80TS51407A

Big-Sert Taper Seat Inserts for Fully Threaded Spark Plugs

Length (mm)Part No
9.40TS51451A
11.00TS51453A
15.00TS51455A
16.80TS51457A
24.50TS51458A
16.80TS51459A
FORD TRITON
24.00TS51460A
FORD Z-tech

Big-Sert Sparkplug Installation Process

1. Ream the Hole

Ream the hole using the stepped reamer.

2. Tap the Hole

Tap the hole using the piloted tap.

3. Seal Insert

Apply high temperature sealant to the outside of the insert.

4. Install Insert

Thread the Big-Sert insert into the hole using the setting tool.

5. Lock Insert In Place

Wind the insert driver tool well through the Big-Sert to lock the insert in place.

Kit Selection Guide

Washer Seat: For sparkplugs with gasket/washer sealing
Taper Seat: For sparkplugs with tapered sealing surface
Carbon Steel: Standard material for most applications
Aluminum: For aluminum cylinder heads to prevent galvanic corrosion

Important Notes

  • • Big-Sert sparkplug repairs are for second repairs only
  • • Measure hole size to confirm need for Big-Sert vs standard repair
  • • Use aluminum inserts in aluminum cylinder heads
  • • Ford applications may require special triple oversized solutions
  • • Clean all metal chips from cylinder before final assembly
  • • Apply anti-seize compound to sparkplug threads

Need Help with Sparkplug Thread Repairs?

Our technical team can help you determine if Big-Sert sparkplug repair is the right solution for your oversized sparkplug hole. Contact us with your engine specifications and hole measurements.

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