Case 1640, 1660, 1680 Axial Flow Combine Repair Manual

Manual Table of Content:

General
Engine (D358, D466 Navistar)
Fuel System
Electrical
Steering
Power Train
Brakes
Hydraulic
Chassis
Manual Extract: Performance Check

1. PERFORMANCE CHECK – Understanding the cause and solution of any problem plus the cor­rect use of equipment is required to make an accurate diagnosis of engine performance. When checking for low horsepower it must be understood that:

a. The injection pump must receive the correct fuel at the correct temperature and pressure.

Any bad fuel, water or wax in the fuel, dirty filters or air in the fuel, must be corrected. Problems with the transfer pump, lines or charge pump must be corrected before you can get good performance. A fuel pressure check under a full continous load will check fuel flow.

NOTE: As fuel temperature goes up, power goes down and there is a reduction in fuel delivery and ratio of volume of air drawn into the cylinder to the piston displacement. As air temperature goes up, power goes down. Hot air from the engine must not enter the air intake.

b. The engine must reach high idle RPM (no load).
c. The brakes must not be applied or any part of the hydraulic system operating. This will not change pressure as the engine does not know where the load is coming from.

d. When checking intake manifold pressure the engine must be loaded enough to pull the engine down to the rated load RPM with the control lever in the maximum speed position. The engine must be held at this load and RPM long enough for maximum performance to be checked. If the load is cut down, engine RPM goes up and intake manifold pressure and exhaust temperature go down.

e. Checking engine performance in the field is difficult as loading the engine down to rated or overload RPM for long periods of time is not easy.
f. There is no replacement for accurate informa­tion by correct tests using good equipment in the hands of good service men.