Usage:
All Truck Engines
Reference: Truck Engine News, September 26, 1984, Page 3, "Change To Maintenance Interval For Valve Lash Adjustment ". Truck Engine News, January 1985, Page 5, "Valve Lash Adjustment Not A Warranty Item " Truck Engine News, April 1986, Page 4, "Adjust Bridge Whenever Valve Clearance Adjustments Are Made ".
Valve lash adjustment procedures are being changed for all Caterpillar Truck Engines (procedures for selected engine models were changed earlier).
Evaluations have determined that the greatest rate of change in valve lash adjustment occurs during the first few hundred hours of operation on a new, rebuilt or remanufactured truck engine. Therefore, Caterpillar no longer recommends a "predelivery" check of valve lash, because initial wear and seating of valve train components has not occurred.
Intake and exhaust valve lash adjustments should be made at the first recommended oil change interval given in the Operation And Maintenance Guide. Thereafter, follow the normal valve lash adjustment intervals. In addition, earlier publications used the term "check" valve lash in reference to valve train maintenance. It is more prudent and cost effective to adjust each valve to the given specification, rather than to "check" valve lash before adjusting.
NOTE: Operation And Maintenance Guides for truck engines will be updated to reflect the above changes.