SERIES 60 ON-HIGHWAY ENGINE OPERATOR'S GUIDE Run the engine for 10 to 15 minutes to seat the belts, then readjust tension. Check and retension belts after 1/2 hour and again after 8 hours or 250 miles (400 km) of operation. Thereafter, check the tension of the drive belts every 100 hours or 6,000 miles (10,000 km) and adjust, if necessary. Earlier-built Series 60 engines have a manual belt tensioner assembly. See Figure 15. If a belt tension gage is not available, adjust the belt tension so that a firm push with the thumb, at a point midway between the two pulleys, will press the belt .50 in. – .75 in. (13 – 19 mm).
Figure 15 Manual Tensioner Assembly with 50 DN Alternator 2-Groove PowerBand The 2-groove PowerBand® is used with the 50 DN alternator. To provide proper running tension for the belt, current Series 60 engines use an auto belt tensioner, which requires no adjustment. See Figure 14. Tighten a new PowerBand® drive belt to 200 lbs (890 N), then run the engine for 10 minutes at 1200 rpm. Stop the engine and allow a 10 15 minute cool down period. Check tension. If less than 150 lbs (667 N), retension to 150 lbs (667 N). Following initial tensioning, measure belt tension every month or every 7,500 miles (12,000 km), whichever comes first. Retension belt to 150 lbs (667 N) at these intervals.
12–Rib Poly-V Belt Tighten a 12–rib poly-V belt to 350 lbs (1,557 N), then run the engine at high idle for 30 minutes. Stop the engine and allow a 10 – 15 minute cool down period. Check tension with tool J 41251–B Figure 14 Auto Belt Tensioner Assembly with 50 DN Alternator All information subject to change without notice. 65 DDC-SVC-MAN-0039 Copyright © 2009 DETROIT DIESEL CORPORATION