5-101.bk Page 13 Friday, March 17, 2006 11:05 AM CLUTCH PILOT FLYWHEEL FRICTION FACE UNDERCUT 200735a Figure 5-10 — Flywheel Resurfacing [212 UB] FLYWHEEL 1. Inspect the flywheel to determine if it requires resurfacing. The wear areas should be measured using a straightedge across the friction face and a thickness gauge. If the wear measurement is 0.020 inch (0.508 mm) or less, the flywheel does NOT need to be machined when operated against ceramic clutch facings. Some machine shop operations can adequately resurface a pot-type flywheel, but may not have the tooling and locating equipment necessary for resurfacing a flat-style flywheel in compliance with the above procedure. 2.
Resurface the flywheel as required. [212 NP] PISTONS Description To ensure satisfactory life of the flywheel, the maximum amount of material that may be removed from the flywheel surface is 0.070 inch (1.78 mm). Since 1991, a two-piece piston has been required to aid in particulates control. To ensure a high level of durability, the piston crown is made from forged steel and the piston skirt is made of cast aluminum. The piston pin bore pedestal and piston skirt are stamped FRONT, and must be facing front of engine. One-piece pistons were used from 1989 through year end 1990.
The procedures for installation are the same except as noted by “two-piece piston.” Current production parts are NOT interchangeable with 1989–1990 production parts. When resurfacing a flat-style flywheel, it is very important that the machine shop NOT leave a step on the friction face outer diameter adjacent to the clutch locating pilot. There is an undercut relief in the corner between the friction face and the clutch locating pilot, and resurfacing must go up to this relief. If resurfacing is done to a depth which would eliminate the relief, a new relief must be recut. Refer back to Figure 5-10.
When resurfacing a flat-style flywheel and attempting to resurface as close to the clutch locating pilot as possible, keep in mind that the pilot must not be altered. The pilot controls location of the clutch; if the locating pilot is altered, imbalance will result. A radius is cut in lower edge of piston skirt to provide clearance for piston cooling nozzle. The piston must be installed with the word FRONT facing front of engine. Page 5-13 200 BENCH PROCEDURES