Pulling Power

Harmonic Damper Removal & Installation Tools


Back story first: I was always in the habit of calling a harmonic device on the end of the crank a “balancer” – that is until I was schooled by an outfit that did custom balance work for the Big 3 in Detroit. As my old acquaintance Andy put it, “a harmonic balancer doesn’t balance anything. The purpose is to dampen harmonics.” There was more to it than that, but fair enough. In my world at least, its now a “Harmonic Damper” and almost all of them are typically press-fit. Back to the topic at hand:

While removing a damper or reinstalling it sounds simple enough the reality is they’re next to impossible to remove and install properly without the right tools. Sure, you might get away with yanking one off with a common three-jaw puller, but you can pretty much be assured the damper will be damaged, if not ruined. In fact, most aftermarket harmonic damper manufacturers explicitly note that the use of a three jaw puller is forbidden with their respective products. Goodbye warranty.

So far so good, but how about installing one? Honestly, a block of wood coupled with the biggest hammer in your tool box or even a dedicated pulley driver isn’t the right answer either. You can easily damage the damper. The same applies if you try use a bolt and pull it on by way of the crank threads. There’s a really (Really!) good chance you can destroy the threads in the crank snout with that practice.

The above is the bad news. The good news and the real answer is to use the appropriate tools. I have a couple of different examples including several vintage GM Kent Moore service jobs in my tool box along with a vintage Moroso example. Equally important, there are many other different versions available out there too (keeping in mind cheap doesn’t usually equate to quality).

A good damper removal tool is simple to use and extremely effective. For the most part, you simply bolt a plate to the face of the damper. Typically, the plate attaches to the same bolt pattern as the crank pulley. The puller usually includes a large diameter, fine thread “screw” that runs through the center of the plate. Using a 1-1/8-inch socket or wrench (socket size depends upon the tool – I’m referencing my old Kent Moore puller here), you simply tighten the screw. The magic of threads goes to work and the damper eases off the end of the crank. Honestly, it’s all incredibly simple and very effective. The first time you use such a tool, you’ll be amazed at the ease of operation and equally amazed at how quick it works. In addition, it creates zero damage to the damper and zero damage to the crankshaft – all good news!

Installation is equally easy with the right tool. Here, the process is a wee bit different. Installation tools typically have an end sized to fit the threads in the crankshaft snout. Some tools like my old Kent Moore installation tool are double ended – one size fits a small block Chevy application (7/16-20) and another fits a big block Chevy application (1/2-20). I also have an older Moroso part number 61741 installation tool, and it has a dedicated 1/2-20 thread for the crank snout for big block applications.

In any case, the idea with the installation tool is to thread it into the crankshaft snout. A word of caution here: There are some situations where the small snout threads on the tool are too long or the crank snout isn’t drilled and threaded sufficiently deep. If the tool bottoms out in the crank, there’s a good chance the thread will snap during the tightening process. Double check it! If it bottoms out, add a washer or two to the end of the tool threads. There’s a huge amount of force applied by the big nut on the tool during the installation process. Next apply a coating of anti-seize to the crank snout, install the key and slide the damper over the snout. It should slide on partially. Some of the tools such as the Moroso job rely upon a large bearing to help distribute the load. Others use a large washer to act as a thrust surface. The bearing and/or the washer are backed by a large nut. The idea here is to tighten the nut with hand tools. Again, like magic, the damper will slide cleanly onto the crankshaft.

Some engines require special tools. Chevy LS engine family is in that group and so are Duramax diesels. ATI offers a slick removal/installation tool for those engines. The part number is ATI918999. With this setup, you’ll have to purchase an additional dedicated installation stud. The principle for use is pretty much like that laid out above.

With any of these tools, harmonic damper removal and installation is a piece of cake. Just be sure to check the threads so that they don’t bottom out and be sure to use anti-seize on the crank snout when installing them. You’ll find what was once a royal pain and a seemingly impossible task (or at least extremely frustrating) turns out to be easy-peasy. Check out the accompanying photos for more details.

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