JasonS
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I found a paper authored by White Motor Corp which outlined what was done to convert the multifuel engine into a suitable tractor engine (D4800 and D4800T). You may find this interesting.
- The military engine was a set of compromises but the basic engine was successful
- Hercules, after building the multifuel for five years was aware of the weaknesses inherent in the engine and able to correct the deficiencies in a period of one year
- Here are the improvements/ corrections
- Compression ratio was reduced from 22:1 to 18:1 to reduce firing pressure and noise while still having "excellent" cold start ability
- The connecting rod was "not adequate" in the multifuel engine. The I-beam section was stiffened nd the pin diameter was enlarged. Note that, based on the engine manuals, the D4800, D4800T, and D5000 actually have the same pin diameter as the multifuel. Often when overhauling the tractors, they will use the multifuel piston to improve cold starting.
- The liner was changed to a press-fit and piston fit (camming) and ring combination improved. This improved piston operating temperature and oil control. Replacement tractor sleeves are offered with a standard or 0.005 oversize fit.
- Bearing clearances were reduced for better oil pressure at elevated operating conditions.
- The oil filter base was modified to prevent oil drainback at shutdown. This was done specifically to have oil pressure at the turbo at startup. Not sure if this is a miscommunication as the tractors have the anti-drainback valve in the externally mounted oil pressure regulator.
- Higher output water pump design which also reduced parasitic horsepower draw. This is a larger diameter pump with curved blades. I don't see how this would ever fit the deuce. https://www.antiquetractorsrus.com/a-403835058pumpwater.aspx
- Cylinder head modified to improve water flow between the valves and reduced thermal distortion of the valve seats.
- PSJ injection pump. Later tractors used the Roosa pump. This requires a different geartrain and injector lines from the tractor.
- The rated engine speed of the D5000 is 2200 rpm. The no load speed is 2370-2420.
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