WHEEL-IMPELLER 1T0042 - Caterpillar

D8, D9 Tractors;
583, 594 Pipelayers;
D353, D379, D398, D399 Industrial And Marine EnginesSUPPLEMENT: 04/06/81SERVICE MAGAZINE, March 16, 1981, PAGES 4 AND 5.In the article, "New Inlet And Exhaust Valves And Valve Guides Have Tighter Fit To Prevent Corrosion And Guide Wear," a change is necessary on page 5. In the top paragraph in the right-hand column, change "2P1313" to "2P2313."--------------- END SUPPLEMENT ---------------Description of Change: New inlet and exhaust valves and valve guides are used in the above products. The new valves have smaller, 9.525 mm (.375") diameter stems. The new valve guides have thread-like grooves inside their bores.
Used together, the new valves and valve guides have a tighter fit than the former valves and guides. The tighter fit keeps combustion gases out of the area between the valves and valve guides.
Formerly, a valve with a 12.7 mm (.500") diameter stem was used. It was possible for combustion gases to get in between the valves and guides. These gases caused corrosion which then caused the guides to wear rapidly. The rate of corrosion and wear is increased when high sulfur fuel is used.
Adaptable To: The new parts are in effect with the Serial Numbers given in Chart A under "First Used." The new parts, used together, are adaptable to the products given in Chart A under "Adaptable To". Chart B has the parts for installation in D9 Tractors, 594 Pipelayers, and D353, D379, D398 and D399 Industrial and Marine Engines. Chart C has the parts for installation in D8 Tractors and 583 Pipelayers. Chart D has the service head assemblies which are available with the new valves and guides.
The guides must have 0.038 mm (.0015") clearance. Some guides will have to be machined; other guides will not. For clearance checks, the valve stem is to be measured about 115 mm (4.50") from the keeper end.
The clearance between the valve and valve guide has an effect on the service life of the valve guide. It is necessary to have the correct clearance to stop the movement of combustion gases and the corrosion and wear which are the results.
Use the 1P7451 Valve Guide Honing Group and 5P8615 Honing Oil to get the final clearance, if necessary. The complete procedure for use of the 1P7451 Valve Guide Honing Group is given in Special Instruction, Form No. SMHS7526.
Use the 1P7430 Valve Guide Driver Assembly and the 2P2313 Valve Guide Driver Bushing to install the valve guides to the correct depth in heads for D9 Tractors, 594 Pipelayers, and D353, D379, D398 and D399 Industrial and Marine Engines. For those shops that do not have these tools, the tops of the valve guides must be 44.45 0.50 mm (1.75 .019") above the