How to Troubleshoot a Mallory Unilite Distributor With No When a Mallory Unilite distributor fails to produce a spark to the plugs, the vehicle will not run. The Mallory Unilite distributor uses an infrared light lens and a sensor between which a wheel with tangs, called shutters, passes. The infrared light makes a completed circuit when the sensor picks it Mallory - holley A legend has returned: the Mallory Unilite Distributor is back! A staple back in the 70’s, the tried and true Mallory Unilite was the original performance distributor. Its small compact housing along with the elimination of old fashioned points made it popular among performance enthusiasts when it came to engine performance.