Case 980 Excavator Service Manual Workshop Guide

Manual Included: Service Manual: 513 pages Specifications: Brand: Case Model: 980 Type: Excavator Manuals: Service Manual Publication Numbers: 9-73476 (May 1977) Language: English Format: PDF Description Table of Contents General Engines Fuel System Hydraulics Track and Suspension Power Train Brakes Mounted Equipment Manual Extract Engine Preignition Preignition is the igniting of the fuel before the normal ignition occurs. This causes wild pinging, severe knock, and power loss. High temperature and pressure from preignition usually burns a hole through the center of the piston. The following are causes of preignition: A. Carbon deposits that remain incandescent. B. Valves operating at higher than normal temperature because of excessive guide clearance or improper seal with valve seats. C. Hot spots caused by an inefficient or damaged cooling system. D. Nozzles set at wrong cracking pressure. E. Detonation or conditions leading to it. F. Sharp edges in combustion chamber. G. Wrong or contaminated fuel.