DenLorsTools.com Summary: Automotive repair blog and video comparing two Miller specialty tools. We have had a lot of questions regarding the Miller 8387 Valve Spring Compressor and the 8516A Rocker Arm Remover/Installation Tools. Both look similar and are for use on Dodge and Jeep 3.7 and 4.7 liter engines. These motors are commonly used in Jeep Liberty, Dodge Durango, Dodge Dakota, Jeep Grand Cherokee etc. *Note – The 8516 has been updated and the newest number has an “A” on the end now making it 8516A. Each tool is for a different job. The valve spring tool allows access at the valve keeper so a magnet can be used to remove it. The 8516A does not have the opening to allow access to the valve keeper.

We’ve had customers ask if they can get by with one and not have to purchase both. The answer depends on what job is being done. We do have many customers that decide to get both. The 8516 cannot be used to change the valves because the valve keeper cannot be accessed. The 8387 can be used to remove and install the rockers (sometimes to access the hydraulic lifters) but there’s a possibility of the keeper falling out of position. When changing valve springs it’s important to follow repair manual instructions which involves putting compressed air into the cylinder to help prevent the valves from dropping. There are also some videos with guys showing how to remove the rocker arms with just a screwdriver. They haphazardly just pry the rocker arm out using the precision machine cam lobe as their fulcrum point. and let the rocker land where it may. This is NOT a good idea. Prying a screwdriver against the cam is sketchy at best. Some videos show a bulky homemade tool being used for the valve spring removal. This can also cause nicks and scrapes on crucial engine components. Making even a small scratch on a cam lobe could lead to rapid wear (with a roller rocker or not). Even a small scratch or nick can cause problems because the cams spin thousands of times even on short trips.

As you can imagine, a nick or scratch can wreak havoc rather quickly. So when working on a 3.7 or 4.7 we recommend using the appropriate tool, either the Miller 8387 or the 8516A or both. These specialty tools are the ones that the Jeep, Chrysler, Dodge dealers use for good reason. They are small, made to fit correctly and do NOT damage the camshaft. Call us at 800-524-9783 to order or see the following links for more information, 3747-123.