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This is Deniz Kaplan's page for Dr. Stansell's Writing 2E class.

Engine Break-in

Engine Break-in is the factory procedure of conditioning the new engine of a vehicle by following specific driving guidelines during the first few hours of its use. The focus of breaking in an engine is on the part called the piston ring of the engine, or the metal between the piston itself and an engine's cylinder wall. There is no universal preparation or set of instructions for breaking in an engine. Most importantly, experts disagree on whether it is better to start engines on high or low power to break them in. While there are still consequences to an unsuccessful break-in, they are harder to obtain on modern engines than on older models. People no longer break in the engines of their own vehicles after purchasing a car or motorcycle as the process is done in production power-plants.

Goal

The goal of modern engine break-ins is the settling of piston rings into an engine's cylinder wall, which has ridges for this purpose. As the engine is powered up, the piston rings between the pistons and cylinder wall will revolve and begin to seal against the wall's small ridges. If the engine is powered up too quickly or not enough (depending on engine), the rings may grind against the ridges and wear them down. The tighter the piston rings are set in, the longer an engine is expected to last.

Preperation

There are important preparations which must be made before the actual process of running the engine. The break-in can take place either in the vehicle or on an engine stand, which is meant to simulate a vehicle. There are no named methods to break in an engine, as each unique engine has specific preparation needs of its own due to factors such as too many different types of engine models, the vehicles they belong to, and conflicting expert instructions. For example, each engine should be lubricated and run on oil specified by its creators or found in a manual.

Process

The main area of controversy among engine break-in instructions is whether to run the engine slowly or quickly to initiate the process. Those who promote raising the power settings steadily will recommend changing the engine setting from low to high powers as to not work the engine too hard and create excessive glazing on the cylinder wall (which would require the pistons to be removed and wall fixed). Other experts disagree and believe that to start the engine at a high power is the best way to effectively set in the pistons. The following are examples of how the two processes can be carried out:

Start high power

Start at rpm, or revolutions per minute, between 2500 and 4000, and run the engine for about 15 minutes while watching so that the oil pressure does not get too high, which is dangerous. After rechanging oil and checking that the engine functions, drive using lower power settings.

A high power setting is relative to the vehicle type, so half as many rpm may be necessary if a car has a smaller cylinder wall.

Start low power

Setting will be around 1500 rpm, run for about half an hour while like the other method checking oil pressure and begin again should there be any over-boiling of the engine's coolant, which is a combination of air, oil, and water. Once this initial step is completed, drive in varying speeds on the road (or stand) by accelerating between speeds of 30 and 50 miles per hour.

Consequences

The following are consequences of a bad engine break-in:

1. Oil will be allowed to gather in the cylinder wall, and a vehicle will use much more of it than necessary.

2. If a ring does not set into the grooves of the cylinder wall but creates friction against them each time an engine runs, the cylinder wall will be worn out.

3. Unsuccessfully setting piston rings into a cylinder wall results in the necessity of new engine parts, or the entire engine depending on how extensive the damage is.

Modern vs. Old Engines

The time it takes to complete an engine break-in procedure has decreased significantly from a number of days to a few hours since modern engines have become more efficient. The factories in which they are produced are also capable of better assembly. For example, older engines had larger ridges in their cylinder walls which made it harder and more laborous to sercure the piston rings within them.