Isuzu KB P190. Service manual - part 337

EXHAUST SYSTEM   6F – 15 

TURBOCHARGER 

MAIN DATA AND SPECIFICATIONS 

 

Engine 4JA1T(L) 

4JA1TC 

4JH1TC 

Model 

IHI RHF4H 

IHI RHF4H 

IHI RHF5 

Turbine type 

Mixed type 

Compressor type 

Backword & rake type 

Maximum permissible speed rpm 

190,000 

190,000 

180,000 

IHI : Ishikawajima Harima Heavy Industries., Ltd. 

 

 

 

6F – 16   EXHAUST SYSTEM 

GENERAL DESCRIPTION 

  

 

 

036LV002 

 

The turbocharger internal mechanism consists of the turbine wheel, the compressor wheel, and the radial bearings. 
These parts are supported by the bearing housing. 

The turbocharger external mechanism consists of the compressor housing air intake port and the turbine housing 
air exhaust port. 

The turbocharger increases air intake efficiency. This results in increased engine power, reduced fuel consumption, 
and minimal engine noise. 

The turbocharger operates at very high speeds and temperatures. Part materials have been carefully selected and 
machined to extremely high precision. 

Turbocharger servicing requires great care and expertise. 

If reduced performance is noted, check the engine for damage or wear. If there is no apparent engine damage or 
wear, trouble with the turbocharger is indicated. 

EXHAUST SYSTEM   6F – 17 

 

  INSPECTION AND REPAIR 

Make the necessary adjustments, repairs, and part replacements if excessive wear or damage is discovered during 
inspection. 

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 

Turbocharger pressure check 

1.  Remove the hose between the waste gate and the 

compressor outlet pipe. 

2.  Connect the pressure gauge. To compressor outlet 

pipe. 

3.  Start the engine and gradually increase the engine 

speed (the vehicle must be stationary with no load 
applied to the engine). 

4.  Check to see that turbocharger pressure rises to 

approximately 141.3 Kpa (1060 mmHg). 
Pressure Gauge : 5-8840-0075-0 

150RY00030

 

 

 

 

Waste gate operation check 

1.  Remove the hose between the waste gate and the 

compressor outlet pipe. 

2.  Connect the pressure gauge. To waste gate actuator.

3.  Check to see that the rod begins to move when a 

pressure of approximately 118 Kpa (885 mmHg) is 
applied to the waste gate. 

Note: 

Do not apply a pressure greater than 150Kpa (1125 
mmHg) to the waste gate during this check. 

150RY00031

 

 

Unit Inspection (Remove Turbo. from engine) 

Check to see the pressure required to move the control 
rod 2 mm is within the limits shown below. 

Kpa/mmHg

4JH1TC 134.8/1011 

4JA1TC 147.7/1108 

 

 

 

150RY00032

 

 

 

 

Contact the “ISUZU MOTORS LIMITED” Dealer service 
department or “IHI SERVICE FACILITY” for major repairs 
and maintenance. 

Important wheel shaft end play and bearing clearance 
standards and limits are included below for your reference.

6F – 18   EXHAUST SYSTEM 

 

Wheel Shaft End Play 

Use a dial indicator to measure the wheel shaft end play. 
Apply a force of 1.2 kg (2.6 lb/11.8N) alternately to the 
compressor wheel end and the turbine wheel end. 

Wheel Shaft End Play 

mm (in)

Standard Limit 

0.03 - 0.06 

(0.001 - 0.002) 

0.09 (0.004) 

 

 

150RY00034

 

 

Wheel Shaft and Bearing Clearance 

Use a dial indicator to measure the wheel shaft and 
bearing clearance. 

Wheel Shaft and Bearing Clearance 

mm (in)

Standard Limit 

0.056 - 0.127  

(0.0022 - 0.0050) 

0.127 (0.0050) 

 

 

150RY00036