In fact, a ‘good’ engine break should include bursts of full acceleration followed by deceleration. (After the engine is FULLY warmed up)
- Blowing full seats places the piston rings against the cylinder walls for a short time without generating much sustained heat.
- Deceleration will ‘float’ the rings inside the ring, drawing extra oil around the pistons to help wash away the debris created during #1. It also allows heat to dissipate into the oil and antifreeze.
EXAMPLE: Entering an interstate using 20-40 seconds of full braking is a GOOD opportunity to avoid attracting the attention of the local police. 👮♂️ 😁
Personally, I follow this ‘accelerate/decelerate’ process multiple times for each tank of fuel for over 40k miles. As long as the MPG continues to climb, I know the rings are closing a little more.
People who take the time to MEASURE compression have reported an increase during the first 20k-30k miles. The general purpose is to fit the rings BEFORE the cylinder covers. After polishing, the rings may never close… and you could end up with an engine burning oil.
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What you do NOT want to do is use CRUZE CONTROL. Constant speeds for miles at a time are a surefire way to wear an engine down. In fact, for the first 10,000 miles, it may be desirable to get off the highway every hour or so and drive back roads. Variable loads on the motor are essential.
