Chevrolet 1956 Truck Operator's Manual page 37

Engine Tune-Up
In order to enjoy the performance and economy which
Chevrolet built into the truck engine it must be kept prop-
erly tuned. Normally this service should be performed every
5,000 miles. A thorough engine tune-up requires the use of
special equipment not generally in the hands of truck owners.
For this reason it is advisable to have this service performed
by a Chevrolet dealer. However for the benefit of those
owners who perform many of their maintenance repair opera-
tions we will outline the operations which should be given
attention when tuning an engine.
Compression. Compression tests should be made before per-
forming tune-up operations to determine the necessity for
internal repairs-an engine with poor or uneven compression
cannot be successfully tuned.
Spark Plugs. Remove, clean and adjust (page 33).
Battery. Check state of charge by testing specific gravity
(page 59).
Battery Cables. Clean and tighten cable terminals.
Distributor. Clean and adjust distributor points. Inspect cap
and rotor (page 31).
Ignition Timing. Check and adjust ignition timing (page 32).
Air Cleaner. Clean air cleaner (page 27).
Manifolds. Tighten manifold bolts to guard against intake and
exhaust leaks.
Valve Clearance. Check and adjust valve lash to proper clear-
ance (page 25). .'
Carburetor. Adjust idling speed and mixture (page 26).
Cooling System. Tighten all hose connections. Check fan belt
adjustment and the cooling system for coolant leaks.
Road Test. After the engine is tuned the truck should be road
tested for performance. During this test the octane selector
should be adjusted for the grade of fuel being used. For best
performance and economy the octane selector should be set to
produce a slight "ping" upon acceleration at wide open throttle .
• 35 •