6. Flywheel
The flywheel required depends on the year of the engine and the size of the bellhousing. Refer to Section 5 to determine which flywheel is needed for the bellhousing chosen. Chevrolet V8 engines made through 1985 use a different flywheel than engines made in 1986 and later. Engines made in 1986 and later are externally balanced and have a 1-piece rear-main seal. This change in block/crankshaft design resulted in a locating dowel for the flywheel (Figure 6-1), a smaller flywheel bolt pattern (Figure 6-2), and a flywheel with a counterweight (Figure 6-3).
Figure 6-1: 1986 and Later Flywheel Aligned With Locating Dowel on Crankshaft
Figure 6-2: 1985 and Earlier Flywheel (left); 1986 and Newer Flywheel (right) [front view]
Photograph courtesy of J. Matthew Daugherty
Figure 6-3: 1985 and Earlier Flywheel (left); 1986 and Newer Flywheel (right) [rear view]
Photographs courtesy of J. Matthew Daugherty
Chevrolet passenger car flywheels are available in two different diameters and can be identified by the number of teeth on the ring gear (153 or 168 teeth). A lightweight version of each type of flywheel is also available and can be identified by the lack of material surrounding the pressure plate mounting holes like the one shown in Figure 6-2. The 1985 and older neutral balance 153-tooth flywheel is commonly available from salvage yards. This flywheel was used on 3.3-L and 3.8-L Chevrolet V6 engines as well as on the small block V8 (except the 400). The 1986 and later 153-tooth flywheel can be quite difficult to locate in salvage yards as they were mostly used in F bodies and most F bodies were equipped with automatic transmissions. The 1985 and older neutral balance 168-tooth flywheel is commonly available from salvage yards. The 1986 and later 168-tooth flywheel is probably easier to find than the 153-tooth flywheel because it was most likely to have been used in truck applications.
Note the automatic transmission flywheel bolts are shorter than the manual transmission flywheel bolts and cannot be used to mount the manual transmission flywheel. New manual transmission flywheel bolts and lock washers are required.
Originally Released 11 February 2002
updated 27 August 2007