Converting 4 Cylinder Air Compressor Air Supply From Boosted To Naturally Aspirated Caterpillar

Converting 4 Cylinder Air Compressor Air Supply From Boosted To Naturally Aspirated

Usage:

ENGINES3176 (7LG),
3176B (9CK),
C-10 (2PN, 8YS),
C-12 (1YN, 9NS),
3406B/C (7FB, 8TC, 4MG, 5YG, 3ZJ, 2EK, 8PN),
3406E (5EK, 5DS, 6TS, 1LW) TRUCK ENGINES EQUIPPED WITH A 4 CYLINDER AIR COMPRESSOR WITH A BOOSTED AIR SUPPLY

THIS TIB REPLACES THE OCTOBER 21, 1998 ENGINE TIB, COMPONENT CODE 1803 "CONVERTING 4 CYLINDER AIR COMPRESSOR AIR SUPPLY FROM BOOSTED TO NATURALLY ASPIRATED". DESTROY THE OCTOBER 21, 1998 TIB. IT WILL NOT APPEAR IN THE SEMI-ANNUAL INDEX.

Problem:

The 4 cylinder air compressor (TF-1400) is failing at an unacceptable rate due to the boosted (turbocharger compressor outlet pressure) air supply. The boosted air supply can cause high compressor head pressure that can result in compressor crankshaft, piston, and rod failures.

Air compressors with a boosted air supply require an Inlet Regulating Valve (IRV) which requires frequent maintenance. If not properly maintained, the IRV can fail which may result in an air compressor failure.

Solution:

Caterpillar recommends that the field population of 4 cylinder air compressors equipped with boosted air supply be converted to naturally aspirated air supply. The parts required to retrofit will be available to help implement this conversion. The parts required to retrofit include the following:

* A 6 inch diameter, 30 inch long aluminized steel pipe assembly with a connection for 1 inch inside diameter rubber hose. (This pipe assembly is to be installed between the customer's air cleaner and the turbocharger air inlet.)

* Two 105-1175 Hoses. (These hoses go between the aluminized steel pipe and the OEM's air pipe.)

* Eight 3E-7424 Clamps. (Use clamps to secure the 105-1175 Hoses to the aluminized steel pipe assembly and the OEM's air pipe. DOUBLE CLAMP as shown)

* A 39.4 inch length of 1 inch inside diameter rubber hose. (This hose goes between the hose connection on the pipe assembly and the air compressor air inlet manifold.)

* Two 7X-7958 Hose Clamps. (For use at each end of the 1 inch inside diameter rubber hose.)

* A 7W-1890 Elbow or a 053-2313 Nipple. (Installed in the air compressor air inlet manifold. Use the one that provides the best connection for your application to the 1 inch inside diameter hose.)

* Two 8M-7065 Gaskets. (These two gaskets are only required if the 7W-1890 Elbow is used. To install the 7W-1890 Elbow, the manifold must be removed from the compressor.)

* A 7W-6492 Pipe Plug. (To be used as an air inlet manifold plug for 3406E Truck Engines only.)

* A 3E-7430 Pipe Plug. (To be used as an air inlet manifold plug for 3406B or 3406C Truck Engines only.)

* A 9S-8008 Plug and 6V-5063 O-Ring Seal. (To be used as an air inlet manifold plug for C-10 and C-12 Truck Engines only.)

Installation Procedure

See the illustrations for the locations of the retrofit components.

1. Remove the IRV, rubber air hose, clamps and fittings that connect the air compressor inlet manifold with the engine air inlet manifold.

2. Install the correct plug in the engine air inlet manifold. [Either a 7W-6492 Pipe Plug (3406E Truck Engines only), or a 3E-7430 Pipe Plug (3406B or 3406C Truck Engines only), or a 9S-8008 Plug and 6V-5063 O-Ring Seal (C-10 and C-12 Truck Engines only).

3. Locate an inlet air supply location between the air cleaner and turbocharger (as close to the air cleaner as possible). Install the 6 inch diameter pipe assembly (cut to length) using the two 105-1175 Hoses and the eight 3E-7424 Clamps (DOUBLE CLAMP).

4. Install the 7W-1890 Elbow or 053-2313 Nipple (as required) in the air compressor inlet manifold.

5. Put the 1 inch inside diameter rubber hose (cut to the proper length) in position between the fitting on the air compressor air inlet manifold and the boss on the 6 inch diameter pipe assembly boss.

6. Use the 7X-7958 Hose Clamps to secure the hose to fitting on the air compressor air inlet manifold and the boss on the 6 inch inside diameter pipe assembly boss.

7. To retrofit a 5 inch air supply, use two 4W-7731 Reducer Hoses (in place of the two 105-1175 Hoses) and two 8T-4987 Clamps (in place of four 3E-7424 Clamps).

NOTE: If the customer prefers to retain the boosted air supply, which requires the IRV, proper service of the IRV is required every 30,000 miles.