Usage:
793 (3SJ),
793B (1HL) Trucks
- SUPPLEMENT: 10/17/94
Service Magazine; September 26, 1994; Page 5; "Maintenance Guidelines For Exhaust Bypass Group". In Step 2, under the headeing FOR THE 111-6118 EXHAUST BYPASS GROUP (WITH YELLOW 113-1572 DIAPHRAGM AND 111-6113 STOP VALVE), the part numbers are not correct. The correct Step 2 follows:
2. Replace the following individual wear items within the exhaust bypass group:
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The exhaust bypass group (wastegate) must be kept in working order to avoid having an overboost situation develop in the engine. Overboost can cause cylinder pressures to exceed the design limits of the engine. For this reason, the wastegate should have the following maintenance performed at the specified intervals.
FOR THE 111-6118 EXHAUST BYPASS GROUP (WITH YELLOW 113-1572 DIAPHRAGM AND 111-6113 STOP VALVE):
At engine midlife (7,000 to 8,000 hours)
1. Replace the exhaust bypass group with a new 111-6118 Exhaust Bypass Group, or
2. Replace the following individual wear items within the exhaust bypass group:
FOR THE EARLIER 4P-4861, 100-8020, AND 107-8753 EXHAUST BYPASS GROUPS:
Every 1,000 Hours
Replace the diaphragm using the yellow 113-1572 Diaphragm. To move the diaphragm maintenance interval out to engine midlife, replace the cover with a 111-6117 Cover, and add the 111-6113 Stop Valve with a 3V-3308 Washer.
At Engine Midlife (7,000 to 8,000 Hours)
1. Replace the exhaust bypass group with a new 111-6118 Exhaust Bypass Group, or
2. Replace the following individual wear items within the exhaust bypass group:
NOTE: 793 and 793B Trucks operating above 12,000 feet, should have the wastegate group removed, or have the boost line to the wastegate disconnected and plugged.