Crankshaft-To-Camshaft Timing Check - Lycoming TEO-540-C1A Maintenance Manual

TEO-540-C1A Engine Maintenance Manual
TEO-540-C1A Engine Maintenance Manual

29. Crankshaft-to-Camshaft Timing Check

NOTICE: This timing check is completed on a partially or fully assembled engine without
removing the accessory housing.
A. Make sure the ignition and all electrical switches are OFF.
B. Disconnect all spark plug leads.
C. Disconnect the starter.
D. Remove one spark plug from each cylinder per the "Spark Plug Removal" procedure in
Chapter 74-20 in the TEO-540-C1A Series Engine Service Manual.
E. Remove the rocker box cover on Cylinder 2 as per the "Exhaust Valve and Guide Inspection"
procedure in Chapter 72-30 in the TEO-540-C1A Series Engine Service Manual.
F. Rotate the crankshaft to position Cylinder 1 piston at Top Dead Center (TDC) on the
compression stroke.
G. Monitor the movement of the intake and exhaust valves in Cylinder 2 as you rotate the
crankshaft to move the piston just past TDC of Cylinder 1.
H. The crankshaft-to-camshaft timing is correct if the intake valve and the exhaust valve in
Cylinder 2 just begins to close as the intake valve starts to open as the piston in Cylinder 1
goes over TDC on compression.
I. If this simultaneous opening and closing of the intake and exhaust valves just past TDC does
not occur, the crankshaft-to-camshaft timing is not correct. Repeat this timing check. If the
results are the same, remove the accessory housing per Chapter 72-25 and complete a check
of the alignment of the crankshaft idlers gears per the "Crankshaft Idler Gear Installation"
section in this chapter.
J. If the crankshaft-to-camshaft timing is correct:
(1) Install the rocker box cover on Cylinder 2 with a new rocker box cover gasket as per the
"Cylinder Installation" procedure in Chapter 72-30.
(2) Install all top spark plugs, each with a new gasket, per the "Spark Plug Installation"
procedure in Chapter 74-20 of the TEO-540-C1A Series Engine Service Manual.
(3) Reconnect the starter.
(4) Reconnect all spark plug leads
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November 2018
72-20
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