Most of us who build stovebolt engines have experienced situations where the harmonic balancer has gotten loose and worn out the crankshaft snout, the Woodruff key, or both. In some extreme situations, the balancer comes off entirely and does a lot of sheet metal and/or radiator damage. While it's possible to recondition a damper with new rubber parts, once one is worn or damaged where it fits the crankshaft, there's not much it's good for but an anchor for a canoe! The 235 splash engine I'm rebuilding has this type of problem, with the crank snout worn about .002" under normal diameter. This will make the press fit of even a good-condition balancer pretty marginal.
Fortunately, there's a fix available- - - - -drill a hole in the crank snout and tap it for the same bolt & washer small-block V-8's used from the mid-1970's on, and keep the damper from loosening up and doing any damage. The trick is getting that hole drilled straight and true, and tapping it correctly. There's only one chance to do it right! The simplest, safest way is to set the crankshaft up in a drill press or Bridgeport mill during a rebuild, and be absolutely sure the hole is straight and true. How about the guy who wants to do the job in the frame, without dismantling the engine? The drill/tap operation is difficult at best, and disastrous in a worst-case scenario.
I am in the process of building a set of two guide bushings to slip over the crankshaft snout, one for the tap drill, the other for the tap, which will assure the hole, and the thread, will be centered and straight on the first attempt, even with the crankshaft in the engine, and if there's enough clearance for a 1/2" drill motor, with the engine in the frame. I've also got a balancer press that can bolt onto the crank snout once it's threaded, to install the balancer without hammering on it. Once I've case-hardened the guide bushings, I'll make the whole setup available for loan to forum members, with maybe a small deposit required just to assure they find their way home in a timely manner! Anybody interested?
Jerry
