Engine Overboost; Incorrect Fuel Or Fuel Contamination - Lycoming TEO-540-C1A Maintenance Manual

(e) Turn the crankshaft by hand to see if the valve lift is uniform or equal for all
cylinders. See if valve rockers lift freely when the valves are closed. Unequal valve
lift is an indication of bent push rods. Tight rockers, when valves are closed, are an
indication of a tuliped valve or a damaged valve lifter. Refer to Chapter 72-30 and
correct any suspected damage before putting the engine back into service.
C. Engine Overboost
(1) Overboost is a condition in which a reciprocating engine (which has a turbocharger)
exceeds maximum rated manifold pressure. While this increase in manifold pressure
supports engine operation during flight, during ground operation and take-off, an excess
manifold pressure can damage the engine if it is not controlled correctly. If the power
control is opened too quickly, the high pressure enters the cylinders and is compressed to
even higher pressure which can cause detonation, overheating, or cylinder damage.
(2) The ECU can control overboost to a limited extent.
D. Incorrect Fuel or Fuel Contamination
(1) Refer to Appendix A in the TEO-540-C1A Engine Installation and Operation Manual
or the latest revision of Service Instruction No. SI-1070 for approved fuels, octane
ratings, and the use of a higher grade fuel for this engine.
CAUTION
(2) Actual damage to the engine from incorrect fuel could be in a range from unnoticeable to
severe damage or failure. Primary damage to the engine caused by incorrect fuel occurs
in the combustion chambers. Tuliped intake valves and burnt pistons from excessive
cylinder head and oil temperatures are evidence of primary damage. If detonation has
been severe enough, further damage will occur to crank pins, main bearings,
counterweights, and valve train components. The extent of damage can vary accordingly
based on the duration of operation, engine power level and the type of fuel used.
(3) Any mixture of unapproved fuels and additive materials that change the octane rating
from the specifications in Appendix A in the TEO-540-C1A Engine Installation and
Operation Manual or the latest revision of Service Instruction No. SI-1070 could be
harmful to the engine.
(4) Because of many variables, it is impossible to be sure of the airworthiness of an engine
that has been operated with incorrect fuel - except by detailed inspection of the engine by
qualified personnel. Therefore, if the engine has been operated with incorrect fuel,
regardless of the power setting or time of operation, as per the latest revision of Service
Bulletin No. SB-398.
(a) Do not continue flight and engine operation with incorrect fuel.
(b) Drain the aircraft fuel system until all fuel tanks are empty in accordance with the
aircraft manufacturer's installation.
(c) If the aircraft manufacturer has a procedure for cleaning and/or purging the aircraft
fuel system after the use of incorrect fuel, follow the aircraft manufacturer's
procedure. If there is no aircraft cleaning and/or purging procedure, service the
aircraft fuel tanks in accordance with the aircraft manufacturer's instructions.
05-50
Page 50
ONLY USE APPROVED FUELS. DO NOT OPERATE THE ENGINE
WITH JET FUEL OR A LOWER OCTANE OR INCORRECT GRADE OF
FUEL. UNUSUAL DETONATION CAN OCCUR AND INCREASE
ENGINE TEMPERATURE AND PRESSURE WHICH CAN DAMAGE
THE ENGINE
TEO-540-C1A Engine Maintenance Manual
TEO-540-C1A Engine Maintenance Manual
© 2018 Avco Corporation. All Rights Reserved
November 2018