5-101.bk Page 10 Friday, March 17, 2006 11:05 AM Inspection Some crankshafts may have journals which are 0.002 inch (0.0508 mm) undersize. They are marked by a streak of white paint adjacent to the journal. Always check journals to ensure using proper size bearing inserts. If crankshaft journals are worn, out of round, or tapered, order a new crankshaft or exchange kit through the MACK parts system. New and exchange crankshafts are available through MACK distribution centers. When ordering an E7 crankshaft, be sure to note V-MAC or non V-MAC application, since crankshafts are not the same. [212 HA] Crankshaft Dowel Pin Replacement 1.
Inspect crankshaft journals for straightness, out-of-round, taper, and surface finish. 2. Visually check crankshaft for any apparent cracks, worn journals and damage to threads, dowel or main drive gear. 3. Magnaflux the crankshaft. This process requires special equipment and application methods. 4. Using standard machinist inspection practice, check crankshaft for straightness. 5. Measure crankshaft journals with a micrometer. Measure each journal in two locations, 90 degrees apart, and record measurements. 6. Check measurements against specifications in the FITS AND LIMITS section of this manual.
The “diamond” locating dowel pins used for installing flywheel to crankshaft have been replaced by blade-style locating dowel pins. The diamond pins were dual diameter-type pins. There was a smaller diameter at the round end than at the diamond end. There are no changes in the size of the hole in the flywheel. However, the crankshaft will have larger holes to accept blade-style pins. The blade-type dowel pin was introduced in May 1992, starting with serial No. 2K. You must use the dowel size that is appropriate for the crankshaft.
(Service old with old, and new with new.) Effective May 1993, all E7 engine crankshafts are equipped with flywheel-to-crankshaft dowel 183GC238 installed in the rear flange. Prior to this date, only V-MAC engine crankshafts had the 183GC238 dowel. Crankshafts in mechanically governed engines did not have a dowel pin hole in the rear flange. However, all E7 engine crankshafts have always had a crankshaft manufacturing locator hole in the rear flange. This hole is approximately 1/2 inch (12.7 mm) in diameter and 3/8 inch (9.52 mm) deep, and is used only in the manufacturing process. Crankshaft regrinding by anyone other than Mack Trucks, Inc.
is NOT recommended due to the tight control required on maintaining geometrical tolerances, and the hardened characteristics of the crankshaft journals and journal fillets. If the crankshaft is not serviceable, both new and reground crankshafts are available through the MACK Parts Distribution Centers. The flywheel locating dowel hole — located directly opposite the manufacturing locator hole — is approximately 9/16 inch (14.29 mm) in diameter by 7/8 inch (22.23 mm) deep in crankshafts made since May 1992 using dowel 183GC238. V-MAC crankshafts made prior to May 1992 have a flywheel locating dowel hole 1/2 inch (12.7 mm) in diameter by 7/8 inch (22.23 mm) deep for dowel 183GC221.
If crankshaft main journals or rod journals are not a standard size, be sure to use properly sized bearing inserts. Bearing inserts are marked with a “P” which follows the part number, and is stamped on the back side of the bearing insert. For example, if a journal is 0.010 inch (0.254 mm) undersize, a 0.010-inch undersize bearing is required and will be stamped “P10”. Page 5-10 200 BENCH PROCEDURES