How to Break In a Diesel Engine

November 5, 2019

Whether you’ve just purchased a brand new boat, or are refurbishing or rebuilding an older one to take out to sea, it’s essential to understand the proper procedures for breaking in a diesel engine. While manufacturers and professional technicians can precision-build the parts and components that make up your outboard or inboard diesel engine, following new engine break-in procedures are vital for allowing cylinder and ring surfaces to set and seal in place for a perfect fit. Running a marine engine break-in procedure will improve your overall performance, extend your engine’s life and prevent excessive oil consumption that can cost you time and money.

When you can incrementally introduce heat and friction through use, your marine engine parts will begin to wear against each other to conform to the shape that will provide the tightest fitting seal essential for achieving optimal, lasting performance.

Do you have to do a new diesel engine break-in? Well, no you technically don’t. However, it can be incredibly shortsighted and careless not to. Taking the appropriate steps to prepare your equipment for heavy-duty use will reduce your chance of leaking fuel and pressurized gas for increased fuel, economy, power and efficiency.

Your new or rebuilt engine break-in procedure is a relatively simple process and can be accomplished quite easily. While the steps in most cases are consistent, there may be variations in your break-in procedures depending on your make and model, and whether or not you’re doing a rebuilt engine break-in. When breaking in a diesel engine, you should always consult the factory-recommended specifications found in your boat’s operating manual.

Break-In Procedures

The ideal method for breaking in an outboard or inboard diesel engine is by running it on a dynamometer in a controlled environment. However, it’s also easily accomplished when already installed in your boat if you lack access to the proper equipment.

Before you start your new diesel engine break-in, you should always start by examining the basics of your marine engine. Look for twisted engine mounts and loose bolts. You should also ensure your wire runs look correct, your drive belt is tight, and the appropriate seacocks are open. Then, you can start your engine and let it idle for five minutes to ensure you’ve got cooling water flow at the exhaust port and full shift control. Check to make sure your oil pressure is stabilized and there is no leaking.

Following your initial startup checks, you can begin breaking in a diesel engine by first lightly operating it for either a few hours or 100 to 150 miles. It’s important to note that during this time, you should avoid prolonged idling as much as possible. You’re only looking to create a small amount of initial heat, so be sure to keep your marine engine in the highest possible gear and run it at no more than 75% to 80% of the power rating. Continue to ramp up the RPMs and load on the engine progressively – not at full tilt. You’ll want to increase the demand put on the engine until you’ve reached 15 hours or 1,000 miles.

If you’re wondering how to break in a rebuilt engine, the break-in procedure remains largely the same, except you’ll want to push it about 1,500 miles for better wear on the parts.

Helpful Tips for How to Break In a Diesel Engine

While running your engine break-in procedure, there are a few helpful tips you’ll want to keep in mind:

Try Not to Idle: While you want to go easy on the engine during break-in procedures, extensive idling can make it work harder than when it is in motion.
Put Towing on Hold: Wait until the engine has been “breaking in” for at least 500 miles to keep the system from getting too hot before towing.
Go the distance: You have to break in a diesel engine to ensure it’s able to deliver peak performance over an extended service life. Wait until you’ve completed the entire process before pushing it to maximum operating capacity.

Shop Quality Replacement Parts for Your Rebuilt Engine Break-In From Diesel Pro Power, Inc.

Whether you’re breaking in a new diesel engine or a rebuilt diesel engine, Diesel Pro Power is your single source for all the parts you need for every step of the break-in procedure. We carry Detroit Diesel and Cummins engine parts, along with Twin Disc and Allison transmission parts and more.

On our easy-to-navigate website, you’ll be able to find the products you’re looking for in a matter of moments for your perfect marine diesel engine. In addition to our excellent customer service, we also offer 24-hour worldwide shipping so your parts will be on your doorstep in no time. Shop Diesel Pro Power today; there’s no better place to buy diesel engine parts online.

If you have any questions, want additional information on how to break in a diesel engine or need assistance placing your order, contact us today. Or, you can give us a call at 888-433-4735 in the U.S. and 305-545-5588 internationally.