Modernizing the 300ZX and the VG30DETT, Fixing Spark Scatter with EPR Engineered Performance

The EPR tensioner is adjusted by removing this Allen lock plug on the bottom of the adjuster plunger.

Then the plunger is turned by another Allen wrench, screwing it out of the housing and moving the arm that the tensioner pully sits on outward, tightening the belt.

This Allen bolt acts like an overtravel stop. It is set full loose and when the correct belt tension is obtained it is tightened down to prevent unconstrained forward movement of the belt pulley wheel.  When the belt is properly tensioned the Allen lock plug is tightened down to prevent the plunger from loosening up.

Here is everything adjusted and in place. When setting the belt tension the engine should be rotated a few revolutions in both directions several times to settle the belt and then the cam timing and belt tension should be double-checked.

With the Engineered Performance VG30DE and DETT tensioner, belt tension and harmonic induced cam timing error and ignition spark scatter is a thing of the past.  This can add a measurable amount of power and stable ignition timing improves safety.  This is a must-have for any highly modded VG engine.


Engineered Performance




  1. I cannot wait to see project 300zx again! So cool to see the motor out getting love. This modification is very common on 4 stroke motocross bikes, as skipping teeth is about all that’s gonna hurt one of those motors .
    Is there somewheres to send the petition for Dave Coleman’s unfinished Silvia and Miata projects

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