Start of Delivery Dial Gauge Holder for Bosch PE/PS80 Pumps (OEM Bosch 1 688 130 085 / 112)

The Marbed 9174 Dial Gauge Holder is a specialized workshop tool for determining the start of delivery (injection timing) in Bosch inline diesel pumps of the PE and PS80 series.

It allows accurate positioning of a dial gauge on the plunger element to detect the exact point where fuel delivery begins.

Correct start of delivery is critical to:

• Engine performance (maximum torque and power)

• Fuel economy (optimized combustion)

• Emissions compliance (avoid excessive smoke/NOx)

• Engine durability (avoid knocking or overheating)

🔧 Technical background

• Principle of operation

  The start of delivery is defined as the moment when the plunger edge closes the intake port and fuel delivery begins. This corresponds to the first upward movement detected on the dial gauge.

• Method of measurement

  1. Mount the 9174 into the inspection port (thread M24×1.5).

  2. Insert a standard dial gauge (Ø8 mm stem, 0.01 mm resolution, 10–30 mm stroke).

  3. Rotate the engine to TDC for cylinder 1.

  4. Zero the gauge, then rotate backward and forward until movement begins.

  5. Compare the plunger lift at the specified crankshaft angle (e.g. 1.20 mm at 18° BTDC).

• Adjustment

  If the measured value does not match the specification, the injection pump must be rotated slightly on its flange until the correct setting is achieved.

• Why use the 9174

  Unlike generic holders, the 9174 has:

  • Exact M24×1.5 thread and protrusion length for Bosch PE/PS80.

  • OEM equivalence to Bosch 1 688 130 085 / 112.

  • Rigid steel body to avoid misalignment or backlash.

Key benefits

• Ensures precise injection timing for Bosch PE/PS80 pumps

• OEM equivalent to Bosch refs. 1 688 130 085 / 112

• Accurate and repeatable measurement of plunger lift

• Strong steel construction with calibrated protrusion

• Fits standard 8 mm stem comparators