Usage:
D346, D348, D349 Engines;
776 Tractors;
777 Trucks
Description of Change: New aftercooler housings for the above models have gussets added to prevent vibration of the metal, which can cause cracks. A similar change is made to the aftercooler cover for all except D349 Industrial and Marine Engine models. The covers with gussets are not used on these models because of other equipment which must be installed, but the new housing will give protection against possible cracks in the cover. Also, on D349 Engines equipped with earlier aftercooler housings, it will be necessary to change the high pressure fuel lines to permit installation of the new housings.
With the aftercooler changes, several other changes have been made on some models. On 776 Tractors and 777 Trucks, the low pressure fuel lines and turbocharger oil lines are changed. The fuel lines have improved clamps to prevent tube vibration, 37° single flare fittings instead of 45° double flare fittings, and different connections to prevent leakage caused by rotation of 90° elbows for alignment purposes. The turbocharger oil lines also have improved clamps to prevent tube vibration. There is more clearance between the oil lines and the end bolts under the aftercooler housing. A new flange on the tube end that fastens to the timing gear housing gives more wrench clearance so the nuts can be tightened better.
The D346, D348 and D349 Vehicular or Truck Engines have similar changes to the turbocharger oil lines, plus some changes to the turbocharger and turbocharger mounting groups. D346 Truck Engines and D348 Vehicular Engines have new attachment fan drive arrangements for use with the new turbocharger oil lines.
Adaptable To: The new parts are directly adaptable to all earlier engines when the necessary parts are used together.
