Chevy 350 Engine Problemsby Rob Wagner
The Chevy 350-cubic-inch engine has perhaps been General Motors' most popular engine since its introduction in 1967. It's no longer produced for new GM cars and trucks, but can be purchased as a replacement engine. Its popularity stems from its compact dimensions, durability and virtual absence of any mechanical idiosyncrasies found in other engines designed more than 30 years ago.
The Chevy 350 is a small-block V-8 with 2.45-inch main journals and 2.10-inch rod journals with four-bolt main bearing caps. Bore is 4 inches and stroke is 3.48 inches. Horsepower ranges from 165 to 370, depending on the year. Crate engines often come in the 350- and 370-hp variety.
The beauty of the Chevy 350 is that whatever performance problems its owner may encounter are typical of any engine. There are no significant performance issues related to the Chevy 350 engine's design. Few problems are also founded in overall performance of used engines as long as they have been well-maintained or are aftermarket crate engines. Yet owners should be aware the 350 is a product of 1960s engineering and needs more frequent maintenance than modern engines.
Typically, a well-maintained Chevy 350 used engine will serve a new owner well. But unless its history is known, some problems may crop up. According to hotrodders.com, one common problem is overheating, which is less of an engine ailment and more of radiator or thermostat issues. Owners should determine whether the radiator matches the 350, especially since the engine probably came from a different make and model car. The wrong thermostat also may have been previously installed.
Chevy 350s typically have problems starting in cold weather, especially with temperatures approaching freezing. According to hiperformer.com, if the 350 fails to start, the culprit is usually found with the automatic choke in the closed position. A closed choke can be determined due to the smell of gasoline from the engine compartment. The air cleaner must be removed and the choke plate be inspected to ensure that it is swiveling to open and close. The choke plate should be open at least 1/8 of an inch.
Chevy 350s used as crate replacement, engines or have been sitting for a long period during a restoration project, may develop a tapping or clicking sound once the engine is running. This is usually due to the oil galleys being blocked or restricted, or due to low oil pressure. The galleys should be cleared and the oil pump replaced. Today's aftermarket oil pumps can generate 60 to 80 psi, about 25 psi better than the standard older versions, according to superchevy.com.
Sometimes odd sounds are normal. The ZZ4 350 Turn-Key Chevy crate engine, equipped with aluminum heads and generating 335 horsepower, can annoy new owners with a slight tapping noise from the camshaft. The camshaft was originally designed for the ZZ3 350 engine and had to be tweaked slightly to ensure it achieved 355 horsepower and 405 foot-pounds of torque and still meet emissions standards.