NUMBER: 2 50 01rev S.M. REF.: Refer to 2.47 ENGINE: 50 DATE: June 2001 REVISION: A vertical bar indicates change. Please discard Service Information Bulletin 2 50 01 dated April 2001 and it s attachment pages. File this bulletin and insert attachment pages in it s place in the service manual. SUBJECT: IMPROVED NATURAL GAS FUEL FILTER INTRODUCTION Detroit Diesel has released an improved fuel filter assembly for the Series 50 Natural Gas on-highway engines only. This change took effect on April 2, 2001. DETAILS AND REASON The fuel filter assembly was changed to remove the bypass feature from the fuel filter housing. This new design improves the oil capturing capability of the fuel filters. See Figure 1. New part numbers are listed in Table 1. Racor Filter Assembly DDC P/N 23517974 (Racor P/N FFC-113) will change to DDC P/N 23529391 (Racor P/N FFC-113 DDC). Fuel Filter Housing Former Fuel Filter Part Number Current Fuel Filter Part Number FFC-113 23528074 23529393* FFC-114 23528074 23529394* * A new center tube (P/N 23529395) must be installed on the current FFC-113 and FFC-114 fuel filter housings. Discard former center tube with hole. Table 1 Former and Current Part Numbers for the Fuel Filter Center Tube New fuel filters do NOT use the bypass spring. Discard bypass spring. Ensure that the correct fuel filter is being used with the correct fuel filter housing unit. FFC-113 and FFC-114 are not interchangeable. Fuel filter 23529393 cannot be used in the FFC-114 fuel filter housing; and fuel filter 23529394 cannot be used in the FFC-113 fuel filter housing.
Figure 1 Current Fuel Filter Assemblies
SERVICE INSTRUCTIONS To avoid injury from an explosion of natural gas, the following precautions must be taken: 3 Do not smoke when installing or servicing the engine or fuel system. 3 Installation or servicing of natural-gas equipment must only be conducted in well-ventilated, natural gas compatible areas. Do not install or service equipment in an enclosed area where ignition sources are present without first ensuring that an undetected gas leak may be safely vented without being ignited. 3 Bleed natural gas lines before installing or servicing any component connected to the fuel lines. 3 Natural gas fuel systems are pressurized. Relieve pressure from any fuel system component prior to installation or service of that component. 3 Use a combustible-gas detector. Liquefied natural gas (LNG) is odorless and cannot be detected by smell. Compressed Natural gas (CNG) may be odorless and may not be detected by smell. 3 Equipment fuel systems are the responsibility of the Original Equipment Manufacturer (OEM). Equipment fuel system guidelines must be closely adhered to when installing or servicing equipment. Refer to OEM guidelines specifying which maintenance procedures require venting of fuel lines and fuel tanks. 3 LNG systems are pressurized and contain extremely cold (-260 F [-162 C]) fluids. Contact the fuel supplier or OEM for LNG safety requirements. Contact with LNG may cause personal injury (freezing). 3 Vent systems on the equipment should be ducted to a safe area whenever equipment is in an enclosed area. Natural gas is highly flammable and explosive and may be extremely cold (-260 F [-162 C]).
Install current fuel filter as follows: 1. Shut off all fuel flow to the filter assembly and bleed off pressure from the unit. 2. Unscrew the bottom fuel filter housing and filter element from fuel filter housing head. See Figure. 3. Remove the two bolts from fuel filter housing head. NOTICE: Ensure the handle rests on the outer edge of the filter head to avoid damage to the threads. 4. Place a screwdriver or equivalent tool with a soft handle through the bypass holes in the center tube. See Figure 2. 1. Filter Housing Head 2. Former Center Tube Figure 2 Removal of Former Center Tube 5. Remove the center tube by gently tapping the metal end of the screwdriver, down away from the filter head.
6. Ensure that correct filter assembly is being used as listed in Table. Discard fuel filter housing O-ring seal, bypass spring and former center tube with holes. 7. Place the fuel filter housing head on a flat surface facing up. 8. Insert new center tube in the center hole of the fuel filter housing head. Use a press to push the center tube into the hole of the fuel filter housing head. Center tube should seat flush at rolled portion of tube. 9. Install fuel filter housing head on mounting bracket with the two bolts and torque to 40.67 47.45 N m (30 35 lb ft). 10. Install correct fuel filter element into fuel filter housing head. 11. Inert a new O-ring seal and install bottom fuel filter housing and torque to 33.90 47.45 N m (25 35 lb ft). 12. Pressurize fuel system and check for leaks. FILTER MAINTENANCE Drain coalescing fuel filters daily. Inspect natural gas fuel filter every 6,000 miles (9,600 km). Replace fuel filter if dirt, debris or foreign objects are present inside of the fuel filter. Also, replace if fuel filter seal is damaged. Oil saturation on the outside of the fuel filter is a NORMAL condition of the oil coalescing process.
ADDITIONAL SERVICE INFORMATION Additional service information is available in the Detroit Diesel Series 50 Service Manual, 6SE50. The next revision to this manual will include the revised information. As a convenience to holders of the Series 50 Service Manual, information in service manual format is attached. The page(s) may be inserted into the manual. Manual insert pages are numbered for insertion into the current Series 50 Service Manual dated June 2000. Service manuals are available from authorized Detroit Diesel distributors. If this bulletin was obtained from the Internet, service manual page(s) are available by returning to the screen SIB Index, selecting attachment pages, and printing the page(s). Detroit Diesel, DDC, Series 50 and the spinning arrows design are registered trademarks of Detroit Diesel Corporation. Copyright 2001 Detroit Diesel Corporation. All rights reserved. Printed in U.S.A.