How to Break In a New or Rebuilt Classic Car Engine Like a Pro

If you check the owner's manuals for many new cars, you'll likely notice they still contain instructions on how to "run in" the engine. Running in a new or rebuilt engine is necessary in order to ensure all moving and rotating parts are able to settle properly in relation to one another.

If you've recently gotten or are planning to get a classic car engine swap in Orange County, knowing how to properly break in your new or remanufactured engine is crucial in order to keep your classic car running properly for many years to come.

We previously examined the engine rebuilding process and gave you some tips on how to determine if your engine should be rebuilt. Now we'll help you get the most out of your rebuilt engine by giving you a brief guide on how to correctly break in a vintage car engine. Read on to learn more.

How long do I keep an engine running after a rebuild?

As a general rule, new or rebuilt engines should be run in for the first 500-1000 miles. The first oil change should occur after the first 300 miles or so. Depending on the engine, you may want to use a special running-in oil at first and then switch to an appropriate multi-grade oil.

This first oil change will flush out any sealant or swarf residue out of the engine, and get rid of any dirt particles. The second oil change is typically viewed as the end of the running in phase: after it, the regular car service intervals should be followed.

Other things to do during the break-in period include:

Examine the engine

Before starting it, make sure that all accessories (eg., alternator, headers, power steering pump, etc.) are tight and that there are no oil or water leaks. Furthermore, check vital components such as carburetor, spark plugs, distributor, and ignition wires.

Protect your flat tappets

Does your rebuilt engine use a hydraulic flat tappet camshaft? If so, you'll need to break it in by keeping the engine in your classic car running at 2000-2500 rpm. Don't place any load on the engine for the first half hour or so.

Prime the pump

Even if the engine was previously dyno-tested, it's still a good idea to prime the oil system with a pre-luber or an engine-priming tool. This will prevent dry start-ups.

Install a quality oil filter

The oil filter should be filled about half way up with oil. The rubber gasket that surrounds it should be lubed with oil and then tightened. Using a high-end filter and using a state-of-the-art motor oil is highly advised.

Don't forget the cooling system

Cooling systems on new or rebuilt engines often contain some trapped air. This can result in water pump cavitation and strange temperature readings. A great way to solve this problem is to fill the system with a 50/50 mix of water and high-end coolant several hours before firing up the engine. This will help clear out the excess air.

Who should I call when I need a top-quality engine swap in Orange County?

Making sure your engine is properly rebuilt, installed, and broken in is crucial in order to ensure your classic car operates correctly and complies with the Federal Motor Vehicle Safety Standards. Here at Chimera Motors, we can do all that for you and more.

Located at the 18061 Redondo Circle in Huntington Beach, close to the Huntington Central Park, we can proudly call ourselves the premier provider of vintage car restoration, maintenance, repair, and storage services in Orange County. Get in touch with us today.