Our balancing procedures are as precise as our machine work on our engines. Balancing is an area that can enhance the ability and performance recovery of the engine if it is done correctly and this is our goal. The factory balance tolerance is between 56 and 80 grams. This works ok on a passenger vehicle at stock power levels. However, 56 grams at 2000 RPM is like spinning a 14lb. weight of unbalance. That same weight of 56 grams at 8000RPM is like spinning 227lbs. of unbalance and this puts so much stress on all of the parts inside the engine and can create breakage and massive power loss.
We first weigh all of the pistons and wrist pins, document all of the weights and then equalize them according to the lightest piston. The piston ring individual cylinder sets and connecting rod bearings all get weighed and documented. The weights of the connecting rod big end rotating weights and the small end reciprocating weights are all individually measured and documented. Then they all get equalized starting with the rotating end and finishing with the reciprocating end. After all of the weights are equalized then the total of each connecting rod weight is confirmed to be equal.
We use all of the documented measurements we previously assembled and we create a bob weight to simulate all of the reciprocating weights and all of the rotating weights that will affect the spinning crankshaft. These bob weights will be installed onto the connecting rod journals. We use a very specific balance worksheet to compute the correct balance bob weight for the specific engine depending on many different factors. It has been proven that our balance procedures can increase horsepower, torque, throttle response, engine RPM recovery, and improves crankshaft harmonic deflection.
The crankshaft is installed onto our Hines Computerized balancing system. All crankshaft specifications and dynamic measurements of the crankshaft are entered. We install the bob weights onto the crankshaft. If the crankshaft is an external balanced engine then the harmonic balancer and the flywheel or flex-plate is then installed in place.
Using the Hines Balancer we spin the crankshaft assembly and it is measured for imbalance both statically and dynamically on the front and rear planes of the crankshaft. Then we compute the process of correction whether it is removing weight or adding weight. There are different processes of this. Removing weight can be drilling and/or grinding weight off of the specific area of the crankshaft. We can also cut weight off the counterweight of the crankshaft on our lathe or mill. Adding weight can be done by welding material and/ or installing heavy metal into the crankshaft counterweight to correct the balance. We slowly continue this until we achieve our Zero balance condition.
The bob weights are removed, the crankshaft chamfered and cleaned for the polishing procedure getting ready for our assembly process.