IO-390-D Series Engine Maintenance Manual
05-30
© 2020 Avco Corporation. All Rights Reserved
Page 38
March 2020
IO-390-D Series Engine Maintenance Manual
5.
Tappet Cleaning
A.
Clean the tappets using the cleaning procedure in the next steps. Refer to the latest
revision of Service Instructions SI-1011 and SI-1514 for details about tappets.
NOTICE:
During disassembly and cleaning, keep the tappet parts together.
B.
Put tappets in a special cleaning basket that has separate compartments to keep the parts
for each tappet as a set, identified but segregated from other tappets.
C.
Put the cleaning basket with the tappets immersed in a petroleum-based solvent.
D.
Flush with petroleum-based solvent and blow dry with compressed air.
NOTICE:
If the cleaned tappets are acceptable per the “Tappet Inspection” in Chapter 72-
20, they can be re-installed.
E.
Apply a light coat of engine oil to the lifter parts before tappet assembly.
6.
Crankcase Cleaning
A.
Grit-blast the crankcase (as necessary) to remove all coatings on the crankcase and engine
mount bosses. Refer to the sections “Grit-Blasting,” “Grit-Blast Media,” and “Grit Blast
Procedure” in this chapter. Make sure there is no dirt, debris, sludge, paint, or any other
substance that could prevent reliable fluorescent penetrant inspection (FPI) or subsequent oil
flow.
B.
Remove all plugs from oil passages in the crankcase.
NOTICE:
Clean the crankcase after all grit-blasting is complete.
C.
Use a stiff bristle fiber (not wire) brush and clean petroleum solvent to clean and flush the oil
passages.
D.
Use compressed air to clean and dry the oil passages.
E.
Prior to installation of a new crankshaft oil seal, clean the crankcase bore, use a clean
disposable lint-free cloth and any of the following cleaning solvents to remove oil, sealant,
and debris from the crankcase, especially the crankcase bore which has the groove for the
crankshaft oil seal:
•
Methyl-Ethyl-Ketone (MEK)
•
M-17
•
Acetone
•
M-114.
•
Napasco SC-200
CAUTION
ONLY APPLY MEK TO THE CRANKCASE, INCLUDING THE
CRANKCASE BORE AND GROOVE FOR THE CRANKSHAFT OIL
SEAL. DO NOT APPLY MEK SOLVENT TO THE CRANKSHAFT OIL
SEAL SINCE MEK CAN CAUSE THE SEAL TO DETERIORATE. BE
SURE TO REMOVE ALL TRACES OF MEK OR CLEANING SOLVENT,
OIL AND SEALANT PRIOR TO INSTALLATION OF A NEW
CRANKSHAFT OIL SEAL.
7.
Grit-Blasting
Do not grit-blast the following:
•
Piston ring grooves and piston skirts
•
Bushings
•
Valve stems
•
Gears
•
Valve guides
•
Any machined surface
•
Bearing surfaces
