Factory Bolt Failure

It’s well documented that the factory timing tensioner bolt is a common failure point under extreme belt tension and harmonic loads.

M10x1.0 Base Thread

Direct upgrade for most factory-based oil pump setups. No modifications required—simply install and go.

 Substantially stronger than OEM bolt, ideal for engines seeing heavy loads and drag racing use.  

M14x1.5 Base Thread

Maximum strength version, requiring modification of your factory oil pump (drilling and tapping required), or drop-in fit with our PHR Billet 2JZ Front Cover (Oil Pump Delete)—specifically designed for wet sump or dry sump race engines using this thread size.

 The M14 version provides significantly greater strength and thread engagement compared to the M10 version—highly recommended for the most extreme builds.  

Extended Design 

  The stud design provides optimal support and thread engagement, but due to its length, requires either no timing cover or modification (drill clearance hole) of your factory timing cover.

 This product is intended for serious race cars where factory aesthetics are secondary to function.

With a thread size of M14X1.5, this is a VAST uprgrade over the factory M10X1.25 thread size:

Practical Notes

✅ Even the M10 version is already a substantial upgrade—you’re taking a known marginal component and giving it ~30% more tensile capacity and far better fatigue resistance (17-4PH is much better in cyclic loading than typical 10.9 steel).

✅ The M14 version is an extreme-duty solution—over 2X the load capacity of the factory bolt. When used with the PHR Billet Front Cover, this is the choice for serious race engines seeing violent harmonics and peak belt loads.