Explanation of TF8 timing marks

Timing marks were added to the side of the cover, next to the ring gear, of the early TF8 converters to make it possible to time the engine when the harmonic balancer is not visible (Fig. 1). The timing marks were mainly found in vans. Since a number of the 12 passenger vans are still in use today servicing churches and senior citizen facilities, it may be helpful to know how to service one. The O of the timing marks are located 21.6 degrees to the left of the bolt hole that is opposite of the offset bolt hole. Fig. 2 Using the degree method of locating the timing mark will work on both the 11 “and 12 “converters. The 727 transmission with the hole in the top of the bellhousing was used with the converters with the timing marks.Ed Lee
Sonnax Industries

– Found in December 2007 Newsletter