So you finally finished rebuilding the engine for your muscle car. All the bolts are torqued, the valve covers in place. Now what? The typical answer is to drop it between the frame rails, hook it up and go. Not so fast cowboy, there is a little more to it than that. Every fresh build needs to be broke in. This is the process of running the engine for the first time to set the camshaft’s wear patterns. This is the most critical moment in an engine’s life, how it runs for the first 20 minutes determines the wear patterns forever; and just like impressions, you don’t get a second chance.
Whether you choose a run stand or install it in the chassis, the process of breaking in an engine is the same. However, there are some very real benefits to using a run stand. At first glance, a run stand might seem like a waste of precious shop space and money, but in reality a run stand can not only save you on both, it can also save you the things that is most valuable- time. While many engine builds go smooth, they don’t always. Imagine a situation where you run into a problem on the break-in; the cam goes flat, there is knock or loss of oil pressure. Any one of those things can ruin your day, not to mention the fact that now you have to yank the engine back out of the car, waste all those fluids and just general unhappiness with the situation. A run-stand allows you to break-in and test the engine without ever having to set it in the car. If something breaks, the repair process is much simpler. Other uses for a run stand include tuning, parts testing and even secure engine storage.
The basic procedure for breaking in an engine starts with having everything correctly installed and ready to start. Don’t even think about firing up the engine if you do not have proper gauges monitoring the vitals- oil pressure, water temperature and RPM are the 3 most important stats you need in this process. The tach is your guide for the run, you need to set the RPMs from 2000-2500 RPMs for the first 20 minutes of the engine’s life. Don’t let the engine idle. This is most important for flat-tappet camshafts. Roller cams are nowhere near this critical; they simply do not have the friction that a flat-tappet cam sees. The cam lobes are not the only parts being broke in, the rings, bearings, valve springs, oil pump, all of these items are being run for the first time, in most cases, so it is important to follow the procedures.
The rings are also in their initial break-in as well. The first 20 minutes of run time begins the ring seating process by smoothing out the minute edges on all the machined parts. One of the key ingredients to all of this is proper break-in oil. Modern break-in oils have more of ZDDP and other additives to protect virgin metals during break-in. Regular engine oils have been regulated by the EPA to remove these protective elements that a new engine needs.
We recently rebuilt a Ford 302 with a flat tappet cam for a 65 Mustang. While we could have just dropped the engine into the car, we wanted to get it tuned in and ready to go so that we wouldn’t have to break our backs working over the fenders. This would also give us the opportunity to address any issues should they arise. As it turns out, that was a good decision. When our Easy-Run Test Stand arrived, it was clear that this was a serious piece of hardware. All of the components were well-designed and the assembly was straightforward. You can even mount an automatic transmission on it if you don’t have a manual-style bellhousing.
After the 302 was setup on the Easy-Run, we fired it up. Everything was going great until we heard a faint tap. Suddenly it got louder. Oil pressure was fine, but the engine developed a miss and we shut it down. After some diagnostics, we determined that a lifter had failed. If the engine had been in the car, we would have had to pull it out, as the final diagnosis was junk in the lifter oil galley that filled the driver-side lifters, keeping them from bleeding off. The only solution was to tear the motor down and clean up what was supposed to have been done before the assembly in the first place.
- Easy-Run Test Stands231 E. Alessandro Blvd. #322Riverside, CA 925081-800-780-0634www.easy-run.net
- Royal Purple, Inc.One Royal Purple LanePorter, TX 77365888-382-6300www.royalpurple.com
- Opima Batteries, Inc5757 N. Green Bay Ave.Milwaukee, WI 53209888-867-8462www.optimabatteries.com
- Ingersoll Rand800 E Beaty StreetDavidson, NC 28036704-655-4000www.ingersollrand.com
- MSD Ignition Autotronic Controls Corporation1350 Pullman Dr Dock #14El Paso, TX 79936915-857-5200www.msdignition.com