Common Engine Problems

The following is a partial list of engine damage that can be easily traced to improper installation or poor care. These types of failures will not be construed as defective workmanship and therefore will not be covered under warranty.

Burned out bearings – caused by lack of lubrication: This type of failure can easily be identified by the pulled and scored surfaces of the bearings that did not completely burn out, or if all of the bearings are burned out. Premature bearing failure can also be caused by a defective or worn out oil pump or pickup screen.

Scored cylinder and pistons – caused by overheating: This type of failure can usually be identified by the fact that more than one piston is damaged and by the discoloration of the pistons and cylinder walls. In some cases, the engines have been run so hot that the cam bearings or heat tabs have melted or the outside paint burned black.

Holes burned in pistons – caused by detonation: This is very easy to identify by the melted look on the head of the piston and possibly a hole burned through the top or down the side of the piston. Broken ring lands can also be caused by detonation or pre-ignition.

Rings worn out prematurely due to faulty carburetor or plugged air cleaner causing excessive amounts of gas to be induced into the combustion chamber washing the oil from the rings, or a defective air cleaner that allows dirt and dust to enter the combustion chamber. This type of failure can be identified by the excessive wear on the cylinder walls as well as on the rings.

Oil consumption in short blocks may be caused by worn valve guides, incorrectly installed valve seals, defective valve seals, plugged up oil return holes, worn out rocker arms and or shafts. This type of problem is usually accompanied by spark plug fouling and can be identified by removal of the intake manifold and inspection of the intake parts. Oily ports and intake valves are positive indication oil is coming from above and not past the rings. Leaking or defective intake manifold gaskets can also allow oil to be sucked into the intake manifold.

Broken pistons caused by bolts, lock washers, etc., or pieces of broken rings from the previous engine that have been left in the intake manifold or cylinder heads. These pieces of foreign materials are sucked into the combustion chamber after the engine is started and can severely damage the pistons.

Broken pistons and bent rods – caused by a hydraulic lock: This type of failure can be identified by the bent rod with no physical marks on the rod indicating something hit the rod to bend it and rod will also have the appearance of having buckled under pressure rather than just plain bending. Hydraulic lock is caused by a small amount of liquid in the combustion chamber and liquid will not compress. When the engine is started, the force of the crankshaft combined with the inertia of the flywheel starter, etc., will create enough power to bend the rod. The liquid could come from the coolant leaking into the combustion chamber, flooding, defective or leaking carburetor allowing gas to drain into the intake manifold and be sucked into a cylinder when the motor is first started.