Crank Trigger Distributor
Racing engines that use crankshaft triggered ignitions use crank trigger distributors for a variety of reasons. The low profile of these distributors allows them to be fitted into tight areas while still delivering sparks accurately. The distributor itself is designed around CNC machined billet aluminum housing. The process of the machine used to create crank trigger distributors produces a very strong yet non-porous housing. This housing has tolerances that are within .001 inches. The inside of the housing holds a long sintered bushing and a sealed ball bearing that work to guide the QPQ coated .500 inch shaft. This helps the engine to experience accurate delivery of sparks even through the highest possible rpms. The coating of the QPQ helps to reduce the risk of corrosion and loss of friction.
The base is injection molded from Rynite. Rynite helps to produce a much stronger base than normal and helps to minimize vibrations from the engine. In addition, this glass reinforced material is very resistant to sparks. Crank trigger distributors are used commonly on racing engines, typically with bronze gears. The triggering system is a very simple concept. The timing wheel contains four magnets that are bolted evenly to the front of the harmonic balancer. There is a sensor that faces the outside of the timing wheel and is mounted on a bracket. When one of the magnets travels past the sensor, a signal is sent to the ignition box. The ignition box will then send out a spark. The spark is amplified within the coil and then delivered to the distributor. This is where it will be routed to the proper spark plug. The timing wheel contains only four magnets instead of eight because the crankshaft will spin two times before all eight cylinders in the engine fire. Because of this, the crank trigger distributor needs only four magnets evenly spaced.
Instead of firing the spark, the distributor is needed to route energy to the proper cylinder which will in turn fire the compressed fuel/air charge. Setting timing with a crank trigger is no more difficult than setting the timing on any other vehicle. A timing light will be needed in order to check the timing. The difference is that instead of rotating the distributor in order to adjust the vehicle’s timing, the sensor is moved. The crank spins clockwise which will move the sensor upwards into the twelve o’clock position. This will decrease the timing. If you set the sensor toward the six o’clock position, the timing will be advanced.
Most drivers now prefer a crank trigger distributor because they help to set the timing mechanisms in a vehicle for optimal power. If you are planning to race on a dirt track, you can switch back over to distributor timing. This is particularly helpful when the surface begins to lose traction which is typically when spinning wheels become problematic. If you simply retard your timing four degrees, you can drop the power in your engine by about five percent or more. This is enough drop in power to give you more control over wheel spinning yet not enough to make your car slower than others or completely uncompetitive. Distributor timing is typically used when peak power is not a major concern. Those who want maximum power prefer to set timing with a crank trigger.
Most automotive parts and supply stores and particularly those that deal in race car engines provide crank trigger distributors. There are also a variety of websites where you can order the distributor for your specific vehicle. Of course, it is important that you provide the proper information such as make and model of your car or truck when ordering to ensure that you receive the proper product.
