Cummins N14 STC, Celect, Celect Plus – Service Manual 020-024   Engine Brake

Install new engine brake housing gaskets and the engine brake housings.

Install the engine brake housing washers and capscrews.

Tighten the capscrews in the sequence illustrated.

Connect the brake harness wire to the electrical connector on each brake housing.

NOTE: Engine brake adjustment specifications are found on the engine brake dataplate (1) located on the exhaust side of the engine brake housing.

The dial indicator method is the only approved procedure for brake lash adjustment. Studies have determined that adjustments made with a feeler gauge are significantly less accurate than those made with an indicator. Excessive lash can overload the engine’s injection train and can result in engine damage.

To maintain a very high level of brake performance on the N14 Plus engine while operating within the valve and injection train capabilities, it is recommended to adjust brake lash with a dial indicator.

NOTE: The dial indicator method can not be used if the adjusting screw has a screwdriver slot. If a screwdriver slot is present, the feeler gauge method will have to be used.

Slave piston adjustments must be made with the engine stopped and cold (stabilized water temperature at 60°C [140°F] or below).

The exhaust valves on the cylinder to be adjusted must be in the closed position.

Rotate the crankshaft in the direction of engine rotation.

Align the “A” or “1-6VS” mark on the accessory drive pulley with the pointer on the gear cover.

When the “A” or “1-6VS” mark is aligned, the intake and exhaust valve rocker levers must be loose for cylinder 5.

Both the intake and exhaust valves are closed when both rocker levers are loose and can be moved from side to side. If both valves are not closed, rotate the accessory drive one complete revolution; and align the “A” mark with the pointer again.

If the valve rocker lever adjusting screws have been loosened and not yet adjusted, watch the valve push tubes as the engine rolls upon the “A” mark. Both valve push tubes will have moved to the downward (valve closed) position if the engine is on the correct stroke.

The instructions using the “A” or “1-6VS” mark to begin the adjustments are for illustration purposes. Adjustments can start at any of the cylinders as illustrated.

Loosen the locknut for the number 5 slave piston adjusting screw.

Install a dial indicator, Part Number 3375006, over the number 5 slave piston adjusting screw. Use the adapter, Part Number 3823826, to mount the dial indicator fixture to the engine brake.

Engine brake slave piston lash can not be set within the +/- .051 mm [.002 in] tolerance with a feeler gauge.

Exceeding the tolerance limits will result in low brake power, or possible exhaust valve/piston interference when set on the low side, or excessive component loading which could lead to damage, when set on the high side.

Engine brake slave piston lash must be set using the dial indicator method.

Tighten the adjusting screw until the slave piston contacts the crosshead.

Zero the gauge with the dial indicator stem resting on the adjusting screw.

NOTE: Engine brake adjustment specifications are found on the engine brake dataplate (1) located on the exhaust side of the engine brake housing.

Loosen the adjusting screw until the indicator needle shows 0.58 mm [0.023 in].

Hold the adjusting screw and tighten the locknut.

Repeat this procedure to adjust the remaining slave pistons.