I have had several inquiries lately revolving around Harmonic balancers and timing/degreeing issues.....so here we go, hope this isn't too boring.
When assembling your performance engine, you should always degree the cam- you spent alot of money on that fancy cam and you want to get the best out of it, but there is at least one more thing you should do while you have that wheel out and that is to insure that when you have the piston at TDC, your balancer also reads zero- I can't tell you how many times I have found an engine that was running subpar or was blown up because of inaccurate timing.
It is best to use a name brand balancer along with the rest of the bottom end-cheaping out on bottom end components and valvetrain is akin to building your house in a swamp. That said, I realize there are often budget restrictions or class requirements ( dirt track comes to mind first) requiring the use of a stock balancer. If your build falls in one of these catagories, some of this may help along with the fact that anyone may be able to use a cheap tool.
First off, degree wheels are cheap enough (or can be made by yo ur Autocad buddy or just by blowing up the picture from the magazine and pasting it on a piece ofaluminum), but crank sockets can be expensive if you don't use them much, and putting the balancer bolt in and out 50 times is a pain.
While I was cleaning up my garage mess one day I came across a couple of old external balance balancers I knew I would never use but rather than throw them away, I thought maybe we could use them for some good. I have tool sets at both shops, and a variety of crank sockets and degree wheels, but I sometimes play with stuff at the house so I made a throw down quick degree wheel for the home shop. This will work for any make car if you have an old balancer or a spun one. Simply hone out the inner bore so it is a snug slip fit, but will go all the way on the crank by hand. If you want, bust the outer ring off to make it lighter. Next, set it on an engine or eyball the proper spot, and line up the degree wheel so two of the bolt holes line up with balancer pulley bolt holes and it is lined up where you can set a pointer for degreeing. Use some short bolts and bolt it on the balancer. Next, get some longer (2 1/2-3" bolts and screw them part way into two of the other holes- you can use these with a pry bar or long wrench to turn the motor- the slip fit allows you to remove and install it quickly to change gear positions when degreeing and then put it right back where it was. One advantage to this tool is you can still use it when the timing cover is on to turn the engine/check TDC.
ON the balancer itself- stock balancers and some of the cheaper aftermarket ones use a solid hub with a piece of rubber wrapped around and then the outer ring-this allows the outer ring to shake or vibrate as necessary, but also as the rubber degrades, it allows the outer ring to break loose and "spin" as the balancer gets older or if your engine revs too quick or high. Once this occurs, your timing will not read correctly and you will either be running too little or too much timing, the latter causing bad performance or blown up engines from too much timing. Maybe more importantly , it can cause broken crank snouts, dented hoods, personal injury or worse....In some cases , budget or rules dictate the use, so here's a trick or two that may help if you must run one. First off, find a known good one and holding them one on top of the other with the crank keyway lined up, verify the one you are using reads zero at the same spot as the known good one- if you are borrowing the good one make a pattern to use next time ( trace the center hole and mark the keyway location, trace the outside and mark zero)....now you have a checking tool.
Another good move is to mark it for future reference so you don't have to take the bolt out to check later. For those of you operating in the daylight in clean enviroments, simply draw a line from the zero mark all the way down the face to the bolt- when the line becomes seperated at the rubber, it's time to replace the balancer. For those of you with 20-200 sight or operating in dirty/dark conditions, drill a hole thru the ring , thru the rubber (you will know when black stuff comes out of the hole) and approximately another 1/4" into the hub. Keep it small- 1/16-3/32". find something that barely fits the diameter and goes in easily by hand (wire coat hangars work fine). Push it all the way in and bend it over to the front of the balancer. Now trim it to a nice length and paint it red so your buddies know it's a tool. Now once every race or two, push it in the hole- when it will no longer go all the way in, replace the balancer. A small hole like this will not upset the balance or weaken the balancer......