This tech tip was provided to us by Steve Hendren at Hendren Racing Engines:
"Did your new 602 or 604 engine come with the balancer shown in the photograph? Have you changed your old style balancer out for the new style balancer? Regardless of the scenario, you MUST check and make sure that the zero (0) mark on the balancer is correct. Since the introduction of this new balancer last year, we have only seen a handful of them that are correctly marked. The vast majority of the balancers we have seen are anywhere from 2-6 degrees retarded, and we have even heard of a few that were as much as 8 degrees retarded. If you're unfortunate enough to have a balancer that is marked incorrectly, then your true ignition timing could be as much as 8 degrees retarded (For instance, you think you're running 34 degrees of timing, but you're actually running 26 degrees of timing). As we all know, severely retarded ignition timing will result in significant power loss, increased water and oil temps, and high exhaust gas temps.
How To Check For Correct TDC (heads on the engine):
There are two methods that work well to check for correct TDC with the heads still on the engine. I'll explain the simplest method. This would be to use a piston stop in the #1 spark plug hole. Using this method, you would simply remove all of the spark plugs from the engine. You would then insert your piston stop into the #1 spark plug hole. Then rotate the engine over by hand, clockwise (you will need to adjust the piston stop depth as you do this) until the #1 piston touches the piston stop. At that point you will mark your balancer in correspondence with the zero mark on your timing tab (602 engines) or the zero notch in your timing cover (604 engines). Once you've done this, turn the engine counterclockwise until the #1 piston touches the piston stop. Mark your balancer again. Then take a pair of dial calipers, measure between your two marks on the balancer, divide that number by 2, and you've found true zero on your balancer. Correctly mark your balancer at zero, and then correctly mark your balancer at 34 degree's (our recommended maximum ignition timing)."
If you would prefer to buy your next engine with the timing already set, this is a service we offer at Crate Insider with our new engine packages. To see all of the engines we offer, Click Here.