Intake/Exhaust Systems - Groups 00
Contents
1. 5 35 Exhaust Pressure Governor Overhaul 36 Turbocharger Replacement 32 Boost Pressure Checking o gt s be sa eao i EE Rw oe CD o 41 Air Filter Element Replacement 29 Charge Air Cooler Leak Test Checking 39 VOLVO Volvo Trucks North America Inc P O Box 26115 Greensboro NC 27402 6115 Volvo Trucks Canada Ltd 6490 Vipond Drive Mississauga Ontario L5T 1W8 http Awww volvotrucks volvo com PV776 TSP144524 300 08 200 Volvo Trucks North America Inc 20002. 37 Group 25 Intake and Exhaust System 6 Install the set screw into the plunger rod Apply sealant to the set screw be fore installing Tighten the set screw to 40 5 Nm 30 4 ft lb 7 Install a new seal into the plunger rod and install the plunger Apply sealant to the boltsand tighten them to 13 2 Nm 10 2 ft lb 8 Install the end cover using new seals Make sure that the seal bottoms in the housing Install the seal with the flat side facing the housing Tighten the bolts 22 to 24 2 Nm 18 2 ft lb 38 40 5 Nm 30 4 ft lb 13 2 Nm 10 2 ft lb 24 2 Nm 18 2 ft lb Service Procedures Group 25 Intake and Exhaust System 2651 06 04 01 Charge Air Cooler Leak Test Checking If the turobocharger fails on an intercooled engine it is essential to check the charge air cooler When consider able oil loss or the presence of foreign material for example broken compressor wheel parts forced into the charge air cooler is suspected take the following mea sures Check the charge air cooler hoses up to the cooler If there are traces of oil at the charge air cooler remove the cooler and clean it internally using a low aroma white spirit type degreasing agent If turbocharger failure results in a broken compressor whell pressure test the charge air cooler to see if it has been damaged by broken compessor wheel pieces Special tools 9996662 9998288 9998289 Note Check the
3. 1 Camshaft 2 Shutter 3 Exhaust pressure governor The Volvo Engine Brake VEB is a combination of two brake systems the exhaust brake and the compression brake Exhaust brake The exhaust pressure governor uses a shutter mounted in the exhaust outlet from the turbocharger This shutter connected to the exhaust pressure governor plunger can restrict the exhaust gas flow This creates a braking effect during the exhaust stroke when the exhaust gases cannot evacuate freely and create an overpressure be tween the pistons and the shutter Compression brake During the engine compression stroke and combustion operating stroke the controlled opening of the exhaust valves creates an overpressure in the combustion cham ber This in turn produces a braking effect on the crankshaft The camshaft on an engine with a compression brake has two extra lobes on each exhaust cam profile The lifting height of the extra lobes is very low when com pared to the normal exhaust lobes To enable the extra lobes to open the exhaust valves the exhaust rocker arms are arranged in a manner by which the valve clear ance can be reduced during the braking sequence ShimShims are available in thickness invtervals of 0 05 mm 0 0002 in Sizes range from 2 0 2 4 mm 0 08 0 094 in and from 3 2 3 95 mm 0 126 0 156 in Thickness is stamped on the shims 4 5 6 Rocker arm Control valve Shim W2003501 Design and Function 11 Group 25
4. 6 Remove the plunger rod spring and shutter Group 25 Intake and Exhaust System 7 Remove the bolts holding the cover the heat shield and the securing flange 12006744 Fig 46 Removing spring holder Carefully tap out the spring holder that secures the spring and the seal 9 Fig 44 Exhaust pressure governor page 36 9 Clean all parts and replace any that are damaged or worn Assembly 1 12006745 Fig 47 Assembly Install the plunger rod into the housing from behind so as to center the spring holder Install a new seal with the beveled edge facing inside the hous ing Install the spring and a new spring holder Service Procedures 12006746 Fig 48 Plunger rod installation Put the plunger rod onto drift 9992610 9992610 in a press Using drift 9998225 press 9998225 on the spring holder until it bottoms in the housing Remove the plunger rod Check to make sure that the spring holder is correctly centered 3 Install the securing flange the heat 13 2 Nm shield and the cover Tighten the bolts 10 2 ft lb to 13 2 Nm 10 2 ft lb 4 Install the shutter spring and plunger rod into the housing 12006748 Fig 49 Depressing spring Compress the spring by hand making sure that the shutter shaft and plunger rod fit together and that the plunger rod fits correctly into the seal Stop ap plying pressure if undue resistance is felt Install the valve collets
5. Exhaust pressure governor Oil delivery and return pipes Clamp Nuts OD E ob General Guidelines and Precautions Always determine the reasons for replacing a tur bocharger before making the repair Correct any noted defects before replacing When replacing a turbocharger always thoroughly read and carefully follow the procedures After degreasing wipe the cooler clean and dry it with compressed air Also check the air pipes and charge air hose If contaminated with oil replace the charge air hose to prevent damage to the rubber The engine oil system and intake system must be kept in good condition to ensure proper turbocharger operation That is change oil and filters at specified times use the correct engine oil and properly care for the air cleaner When replacing a turbocharger use compressed air to remove any rust or carbon flakes from the exhaust mani fold Carbon flakes can damage the turbine of the new unit lt is also important to clean the intake pipe from the air filter Pieces of broken components can remain in the pipe and cause immediate turbocharger failure Also always check to be sure that the injection equip ment is in good condition Note Once the turbocharger is installed put oil in oil supply port to ensure proper turbo lubrication Once turbo is sufficently lubricated you can crank the engine Removal 1 Remove the air cleaner hose from the turbocharger Group 25 Intake and Exhaust Sy
6. jury or death HOT ENGINE Keep yourself and your test equipment clear of all moving parts or hot engine parts and or fluids A hot engine and or fluids can cause burns or can permanently damage test equipment 12006979 Fig 40 Exhaust manifold Note It is easy to get the wrong impression from ex haust manifold leakage mixture of moisture and soot This mixture may drip down on the turbo and could eas ily be mistaken for an oil leak from the turbo 34 Service Procedures Removal 1 Remove the bolts holding the exhaust manifold and lift off the manifold 2 Disassemble the exhaust manifold and remove all sealing rings Clean the ex haust manifold and the cylinder head Installation 3 Use compressed air to blow any carbon out of the manifold Then as semble the manifolds Wear appropriate eye protection Note Three sealing rings must be in stalled at each side Install the sealing ring with the smallest diameter in the middle 4 Install the exhaust manifold using new gaskets Begin by lining up all three manifold sections onto the cylinder head starting with section A Note Make sure that the sleeves fit correctly into the milling of the exhaust manifold and install the gaskets with the graphite surface facing the cylinder head 5 After applying anti sieze to the mani fold bolts and turbo studs screw the bolts in by hand starting with section A and then sections B and C 6
7. Intake and Exhaust System D12C The VEB solenoid has been moved to the center of the rocker shaft The oil supply is internal rather than having the external piping visible Control Valve The control valve is mounted on the cylinder head under the valve cover and is connected to the oil system ahead of the rocker arm shaft Its purpose is to reduce the oil pressure to the rocker arms while the engine is operating compression brake not activated There is always full system oil pressure to the control valve intake 1 because the intake is connected via a pipe to the lube oil gallery in the cylinder block The oil pressure to the rocker arm shaft can be increased via a solenoid valve 2 mounted on the control valve from ap proximately 100 kPa 14 5 psi while the engine is operating to more than 200 kPa 29 psi during com pression braking While the engine is operating the oil pressure is reduced after the control valve by the plunger 3 being held in balance by the force of a spring 4 and the oil pressure in the oil chamber 6 on the opposite side of the plunger When the solenoid valve is activated the oil chamber 6 is drained and the spring 4 presses the plunger 3 to its end position The plunger completely opens the oil outlet 5 to increase oil pressure to the rocker arm shaft 12 OO P Go MA Design and Function A SAN T2006835 Fig 4 Control Valve Oil inlet Solenoid valve
8. Tighten the bolts cross wise starting 25 Nm with section A and then sections B 18 ft lb and C Torque to 25 Nm 18 ft lb See illustration page 26 7 Begin the tightening sequence again 48 8 Nm however raise the torque to 48 8 Nm 35 6 ft lb 35 6 ft lb Group 25 Intake and Exhaust System 8 Start the engine and run until it reaches operating temperature 9 Verify the torque at 48 8 Nm 35 6 ft lb 2538 03 02 01 Exhaust Pressure Governor Replacement AN DANGER Before working on a vehicle set the parking brakes place the transmission in neutral and block the wheels Failure to do so can result in unexpected vehicle movement and can cause serious personal in jury or death HOT ENGINE Keep yourself and your test equipment clear of all moving parts or hot engine parts and or fluids A hot engine and or fluids can cause burns or can permanently damage test equipment Removal 1 T2006942 Fig 41 Removing air line Remove the air line from the exhaust pressure governor Service Procedures T2006940 Fig 42 Removing air pressure governor Remove the bolts and lift off the ex haust pressure governor Installation 3 12006941 Fig 43 Cleaning shutter housing Clean the sealing surface of the shut ter housing 4 Install the new exhaust pressure gov ernor Install the air line 5 Apply parking brake and place shift lever in neutral Start the engine an
9. brake LA 12006832 Group 25 Intake and Exhaust System Compression Brake The exhaust brake is always engaged in conjunction with the compression brake In the compression brake induction phase the exhaust brake creates an overpres sure in the exhaust manifold making the compression brake more efficient Induction phase The induction phase begins at the end of the intake stroke and continues slightly into the compression stroke The piston travels towards its bottom dead center posi tion and the camshaft induction lobe opens the exhaust valves for the time required to fill the cylinder with the overpressure created by the exhaust brake in the ex haust manifold When the induction lobe closes the exhaust valves the cylinder has an overpressure at the start of the compres sion stroke This overpressure considerably increases the compres sion during the compression stroke which in turn creates a powerful braking effect during the upward movement of the piston Decompression phase At the end of the compression stroke when the piston is nearing its top dead center position the camshaft decompression lobe opens the exhaust valves and re leases the pressure out of the cylinder Shortly before the bottom dead center position the ex haust valves are opened by the ordinary exhaust lobe During the exhaust stroke the counterpressure is cre ated in the exhaust manifold which in turn has a braking effect because
10. function of pressure gauge 9996662 before using it Attach it to an air supply and set the pressure to 100 kPa 14 5 psi with the regulator valve AN DANGER Before working on a vehicle set the parking brakes place the transmission in neutral and block the wheels Failure to do so can result in unexpected vehicle movement and can cause serious personal in jury or death HOT ENGINE Keep yourself and your test equipment clear of all moving parts or hot engine parts and or fluids A hot engine and or fluids can cause burns or can permanently damage test equipment Never disconnect an air system component unless all system pressure has been depleted Failure to de plete system pressure before disconnecting hoses or components may result in their violent separation and can cause serious bodily injury Service Procedures Make sure that the gauge pressure never exceeds 100 kPa 14 5 psi Failure to do so can result in personal injury Always wear appropriate eye protection to prevent the risk of eye injury due to contact with engine debris or fluids W2000715 Fig 50 Pressure gauge 1 Shut Off Valve 2 Reduction Valve Connect the pressure gauge to out side air source and set the gauge reading to 100 kPa 14 5 psi using the reduction valve The knob of the reduction valve is locked by a ring which is engaged by pulling up on the ring and pushing down to release 2 Close the shut off valve For the
11. in the ex haust pipe with a plug or in some other suitable manner 42 System Check T2006988 Measuring equipment 1 2 3 4 Damper Pressure gauge Steel pipe Union T2006983 Outlet location Feedback One of our objectives is that workshop personnel should have access to correct and appropriate service manuals where it concerns fault tracing repairs and maintenance of Volvo trucks In order to maintain the high standards of our literature your opinions and experience when using this manual would be greatly appreciated If you have any comments or suggestions make a copy of this page write down your comments and send them to us either via telefax or mailing directly to the address listed below To From Volvo Trucks North America INC 0 ccccccccnnnnnnnnnnnnnnnnnnnnnnnnnnnnr nn nn rn n nr nnnnnnnnnns Dept 516 Service Publications cmmcccncnnnnnnnnnnn nn non nn nn nr nn rr ran rn nr nn rra rre nnnnnnnns 7825 National Service Road o cnc PO Box 26115 Ro a eaea eaa ariari iaei Greensboro NC 27402 6115 eccccnnnnnnnnnnnnnnn nn rra nn rrrn nr rn nan n nn rrrrnnnnn nn nrrrnnnnnnnns USA Fax 336 393 3170 Comments proposals 2512 03 02 01 2516 03 04 01 2538 03 02 01 2538 04 04 01 2551 03 02 02 2559 06 02 02 2562 03 02 01 2651 06 04 01 Operation Numbers Intake Manifold Gasket s Replacement 30 Exhaust Manifold Gasket s Replacement 34 Exhaust Pressure Governor Replacement
12. is overcome and the plunger 1 moves so that it no longer influences the ball 3 The spring 5 presses the ball 3 against the seat and prevents the oil contained above the plunger 4 from flowing past the ball 3 This forms high oil pressure above the plunger 4 14 AOUN OS GO M Design and Function W2003502 Fig 6 Rocker arm assembly side view Spring tab Non return valve Rocker arm plunger Shims T2006834 Fig 7 Rocker arm assembly top view Plunger Spring Ball Rocker arm plunger Spring Group 25 Intake and Exhaust System Rocker Arm Plunger The purpose of the rocker arm plunger is to eliminate all valve clearance during the compression braking Engine Operation When the engine is operating compression brake not activated there is reduced oil pressure approx 100 kPa 14 5 psi via the control valve to the rocker arm shaft and the rocker arm non return valve 1 is open Oil can flow freely through the non return valve in both di rections As a result no oil pressure is built up between the rocker arm plunger 2 and the rocker arm The set valve clearance is great enough to prevent the camshaft induction and decompression lobes from open ing the exhaust valves The valve mechanism operates the same as on an en gine without a compression brake in other words only the exhaust lobe opens the exhaust valves Compression Braking During compression braking the
13. the exhaust pressure governor shutter is still restricting the flow of exhaust gases out of the turbocharger Design and Function 12006830 Fig 12 Charging phase 72006831 Fig 13 Decompression phase Group 25 Intake and Exhaust System Crankcase Ventilation D12C The D12C has new crankcase ventilation with its outlet from the upper timing gear cover The timing gear cover is designed with an oil trap to pre vent oil from escaping through the ventilation tube Design and Function 12012791 Fig 14 Crankcase Ventilation D12C LIAN ll W2003503 Fig 15 Crankcase Ventilation D12B and D12C W2003504 Fig 16 Crankcase Ventilation D12A Group 25 Intake and Exhaust System Exhaust Pressure Governor The exhaust pressure governor EPG acts as an exhaust brake when slowing the vehicle down It also speeds en gine warm up by applying a load to the engine during idle and warm up Engine load is created by the EPG throttling the flow of exhaust gases causing the engine to work against a backpressure This increases combus tion temperature and shortens the warm up period On engines without a pre heater the EPG is activated before the starter motor is engaged For engines with a pre heater the EPG is activated after pre heating start up and post heating have taken place The EPG is activated by a control pressure of about 200 kPa 29 psi by a combi relay when it
14. Plunger Spring Oil outlet Oil chamber Group 25 Intake and Exhaust System Camshaft on Engine with Compression Brake The camshaft on an engine with a compression brake has an induction lobe 1 and a decompression lobe 2 in addition to the normal exhaust lobe 3 on each cam profile for the exhaust valves The induction and decompression lobe lifting height is 0 8 mm 0 032 in above the basic circle which is equiv alent to approximately 1 1 mm 0 043 in at the valve bridge The induction lobe is positioned so that it opens the ex haust valves at the end of the intake stroke and holds them open until the beginning of the compression stroke The decompression lobe is positioned so that it opens the exhaust valves at the end of the compression stroke In order for the induction and decompression lobes to open the exhaust valves the valve clearance must be re duced to zero by the activation of the non return valve and plunger located in the rocker arm for the exhaust valves Design and Function 12006826 Fig 5 Cam Shaft Profile 1 Induction lobe 2 Decompression lobe 3 Exhaust lobe Group 25 Intake and Exhaust System Exhaust Rocker Arms The exhaust rocker arms on an engine with a compres sion brake are larger than those on a conventional engine The rocker arm includes a non return valve 2 and a plunger 3 with a pressure limiting valve the purpose of which is to regulate the oil flow duri
15. Service Manual Trucks Group 250 600 Intake and Exhaust System D12 D12A D12B D12C PV776 TSP144524 VOLVO Foreword The descriptions and service procedures contained in this manual are based on de signs and methods studies carried out up to August 2000 The products are under continuous development Vehicles and components produced after the above date may therefore have different specifications and repair methods When this is believed to have a significant bearing on this manual supplementary ser vice bulletins will be issued to cover the changes The new edition of this manual will update the changes In service procedures where the title incorporates an operation number this is a refer ence to an S R T Standard Repair Time Service procedures which do not include an operation number in the title are for gen eral information and no reference is made to an S R T The following levels of observations cautions and warnings are used in this Service Documentation Note Indicates a procedure practice or condition that must be followed in order to have the vehicle or component function in the manner intended Caution Indicates an unsafe practice where damage to the product could occur Warning Indicates an unsafe practice where personal injury or severe damage to the product could occur Danger Indicates an unsafe practice where serious personal injury or death could oc cur Volvo Trucks North America In
16. c Greensboro NC USA Order number PV776 TSP144524 2000 Volvo Trucks North America Inc Greensboro NC USA All rights reserved No part of this publication may be reproduced stored in retrieval system or transmitted in any forms by any means electronic me chanical photocopying recording or otherwise without the prior written permission of Volvo Trucks North America Inc Contents A sans O oii io OI 3 RETIROS au a adios 5 UE 5 TOD Sian A a 7 apoc KEE 7 Special EQUIEMIBnE E 8 Design and FUNCION ora 9 Intake and EXISTEN nai 9 A a NOAR 9 D A Ee 9 Engines wihout E 10 Engine Droe acan aan een ain 11 EN 12 EE De EE 18 E y ita 18 Exhaust Pressure Govino eii ee 19 DR le 21 EPO COMMO VANG oi A GS O 22 DMA rar 22 DOTES GEN 22 e A E 23 TOA is 24 O 24 ESMAS MARMO rasca 25 eu E EE 26 TEGUISE NOOO sica cri 27 Air Restriction Indicator Checking iriivininiccinnanicica dica 27 GE 29 Air Filter Element Replacement ssccoiannicciarasicnnaror aia ar caia 29 Intake Manifold Gasket s Replacement A 30 Removal o gi 31 IC E sr aan pp RE RR RA 31 Turb charger Replacement cion rr a rice 32 SE WE 32 A A A A 33 Exhaust Manifold Gasket s Replacement occccnnccccnnnccccconanccnnnnconons 34 Turbocharger Removed sr a a ra ag 34 Exhaust Pressure Governor Replacement ooocccconocccccnnccccconncccnnnnccnnns 35 Exhaust Pressure Governor Overhaul 36 WE Removed ni e EE 36 A O SAAE EEE 36 E nt E 37 Charge Air Cool
17. control valve does not reduce the oil pressure so an oil pressure of at least 200 kPa 29 psi is delivered to the rocker arm shaft The pressure in the rocker arm non return valve 1 be comes so great that the plunger in the non return valve is moved out of its rest position and the ball now func tions as a non return valve Pressure is built up between the rocker arm plunger 2 and the rocker arm The plunger is pressed out and presses the rocker arm roller against the lobes on the camshaft In this way the valve clearance is eliminated and the lifting height on the in duction and decompression lobes is sufficient to open the exhaust valves The rocker arm plunger is fitted with a pressure limiting valve 3 When the oil pressure between the rocker arm plunger and the rocker arm becomes too great the pres sure limiting valve opens and oil can exit through the hole in the bottom of the plunger The opening pressure of the pressure limiting valve is governed by the force of the valve spring Design and Function 72006828 Fig 8 Rocker Arm Plunger 1 Non return valve 2 Rocker arm plunger OQ yg e 12006836 Fig 9 Rocker Arm Plunger 1 Non return valve 2 Rocker arm plunger 3 Pressure limiting valve Group 25 Intake and Exhaust System Control System The engine brake is connected to the throttle pedal and is activated when the pedal is completely released ac cording to the selection made with the en
18. ctly on the air cleaner the piston is usually drawn downward into view as the element loads with dirt It locks into full view only after the restriction caused by a dirty element reaches the rated value of the indicator Design and Function RESTRICT W2000740 Fig 24 Air restriction indicator WX WG AC dash mounted 7d oia O O 9 W2003505 Fig 25 Air restriction indicator VN VHD VNM located beneath the air box GEN META Fig 26 Air restriction indicator VN VHD located on the air pipe W2000741 Fig 27 Piston type air restriction indicator WG 23 Group 25 Intake and Exhaust System Turbocharger The turbocharger is driven by the exhaust gases from the engine passing through the turbine housing on their way out into the exhaust system The flow of exhaust gases causes the turbine wheel in side the turbine housing to rotate On the same shaft as the turbine wheel is a compressor wheel The compres sor wheel is mounted in a housing which is connected between the air cleaner and the intake manifold When the compressor wheel starts to rotate air is drawn in from the air cleaner compressed and forced into the cylinders of the engine but not before it has been cooled down after passing through the charge air cooler D12A The turbo used on the D12A engine is NOT interchange able with turbos on other D12 engine versions 24 Desig
19. d check for proper operation and leaks 35 Group 25 Intake and Exhaust System 2538 04 04 01 Exhaust Pressure Governor Overhaul Unit Removed AN DANGER Before working on a vehicle set the parking brakes place the transmission in neutral and block the wheels Failure to do so can result in unexpected vehicle movement and can cause serious personal in jury or death HOT ENGINE Keep yourself and your test equipment clear of all moving parts or hot engine parts and or fluids A hot engine and or fluids can cause burns or can permanently damage test equipment T2006749 Fig 44 Exhaust pressure governor 1 Setscrew 11 Valve Collets 2 Bolts 12 Bolts 3 Plunger 13 Cover 4 Seazls 14 Heat shield 5 Plunger Rod 15 Securing flange 6 Spring 16 Nut 7 Spring holder 17 Nut 8 Spring 18 Housing 9 Seal 19 Seals 10 Shutter 20 Seals 21 End cover Special tools 999 2610 999 8225 999 8246 36 Service Procedures Disassembly 1 Remove the end cover from above the plunger 2 Remove the bolts and take out the plunger 3 Remove the seals 4 20 and 19 Fig 44 Exhaust pressure governor page 36 4 Remove the set screw on the plunger rod 72006747 Fig 45 Removing collets Place the exhaust pressure governor into a press Compress the spring enough to remove the valve collets Note Do not press more than necessary to remove the collets Com pressing the spring fully can damage the cover
20. e pipe one to two pipe diameters upstream from the turbocharger inlet in a straight section of pipe Tur bocharged engines should be under full load long enough to allow the turbocharger to reach maximum speed Note Dust conditions and accumulated mileage deter mine the interval for replacing the air cleaner element The air cleaner should be inspected every 24 000 km 15 000 miles and replaced as necessary The air cleaner element should be replaced at least once a year regardless of service or restriction indicator readings Troubleshooting 27 28 Group 25 Intake and Exhaust System Service Procedures Service Procedures 2562 03 02 01 Air Filter Element Replacement AN DANGER Before working on a vehicle set the parking brakes place the transmission in neutral and block the wheels Failure to do so can result in unexpected vehicle movement and can cause serious personal in jury or death HOT ENGINE Keep yourself and your test equipment clear of all moving parts or hot engine parts and or fluids A hot engine and or fluids can cause burns or can permanently damage test equipment When removing and installing the intake manifold on engines equipped with VEB keep the work area as clean as possible to prevent impurities from entering the oil system This also applies to the compression brake oil delivery pipe between the cylinder block and intake manifold Removal 1 Apply parking brakes make sure the
21. eater does not engage at coolant temperatures over 10 C 50 F At a coolant temperature of 10 C 50 F the preheating time is 25 seconds At coolant temperatures below 15 C 5 F the preheating time is 55 seconds Preheating time increases linearly between 10 C 50 F and 15 C 5 F The post heating time is always the same as the pre heating time D12C The D12C is equipped with a new preheater The func tion of the starting heater is similar for both vehicle variants but the location of the relay differs The pre heater on both engine variants is grounded to the engine block through the intake manifold Design and Function Fig 1 Preheater Fig 2 Preheater D12C T2006975 W2003281 Group 25 Intake and Exhaust System Engines without Preheater On engines not equipped with a preheater engine coolant temperature determines the point at which fuel injection begins while starting The crankshaft rotates an extra number of turns to increase cylinder temperature before fuel injection begins This gives more reliable starting and reduces exhaust emissions during cold starts down to about 15 C 5 F This means that the crankshaft may need to rotate about 3 4 rotations before fuel injection begins and the engine fires An exhaust pressure governor is activated during start up Design and Function Group 25 Intake and Exhaust System Engine Brake Fig 3 D12 Engine
22. er Leak Test Checking ooocconcccnnoconocccnoncccncncnnnnnnnoos 39 System e sera RA RR 41 Boost Pressure Checking ai 41 Exhaust Ba kpressure Checking assuianeanamanarinnoantenntoaacenioanviaanednf anos 42 Pressure Testing Outlet LOGAN ici 42 Backpressure Measuring Techniques 42 Feedback Operation Numbers General General W2003244 Group 25 Intake and Exhaust System Lay j pA A gin CARA This information covers the Intake and Exhaust System for the D12 D12A D12B and D12C engines D12C Engine Group 25 Intake and Exhaust System Specifications Specifications Intake and Exhaust System Maximum Restriction Rated speed full load oooocoooccconiccccconccccononccnononacnnonnnncnnnnncncnnnncnnnnnnncnnnnnns 6 2 kPa H20 25 in Air Cleaner torque el E Oe 9 2 Nm 7 2 ft lbs Metall iii A A AA ees Erde 20 2 Nm 15 2 ft lbs For Specifications including torques refer to Service Manuals 200 890 Specifications D12C 200 850 Specifiications D12B 200 820 Specifications D12A IMPACT Function Group 25 Info Type Specifications Group 25 Intake and Exhaust System Specifications Group 25 Intake and Exhaust System Tools Tools Special Tools Servicing the VE D12 intake and exhaust systems requires the following special tools The tools are available from parts departments of Volvo Trucks North America Inc When requesting tools provide the appropriate numbe
23. es with an exhaust brake only With the HI LO switch in the HI position the VEB is activated both the exhaust pressure governor and com pression brake are switched on In addition to satisfying exhaust brake prerequisites the following conditions must be met e Coolant temperature above 70 C 158 F e Vehicle speed must be greater than 12 km h 7 5 mph e Engine temperature must be above 43 C 110 F For VN VHD engine exhaust brake switches are located on the dash 5 see Fig 21 Engine brake switches for VN VHD page 20 20 Design and Function ENGINE BRAKE ENGINE BRAKE W2001002 Fig 20 Engine brake switches for WG and AC Dual two position switches 1 2 a A O N ON OFF HI VEB LO exhaust brake W3004361 Fig 21 Engine brake switches for VN VHD Left Dash Switches Driving Light Switches Pneuamtic Switches Auxiliary Switches Right Dash Switches Group 25 Intake and Exhaust System D12C The EPG on the D12C has a new air valve The valve is located on the right rear edge of the engine block and is controlled by current from the EECU There are two on off valves and two reduction valves in the valve body Design and Function 12012788 Fig 22 Exhaust Pressure Governor D12C 21 Group 25 Intake and Exhaust System EPG Control Valve The exhaust pressure governor is controlled by a valve that regulates air pressure to the EPG The exhaust pressure
24. gine brake switch on the instrument panel The selection made with this switch also regulates en gine braking activated by the cruise control Note The engine brake functions as long as the engine control system has received signals from engine sensors indicating that the required preconditions for engine braking have been met For example the engine speed must be greater than 1100 rpm the vehicle speed must be greater than 12 km h 7 5 mph and the engine tem perature must be above 70 C 160 F The switch has three positions 0 No engine brake engaged 1 Exhaust brake EPG 2 Exhaust brake and compression brake VEB Exhaust Brake When exhaust braking the exhaust pressure governor EPG is activated with a control pressure of approxi mately 750 kPa 110 psi At this point the shutter is forced out of the EPG and into the shutter housing This restricts the flow of exhaust gases out of the cylinders as the shutter blocks the outlet from the turbocharger Restricting the flow of exhaust gases forms an air cush ion between the shutter and the piston crowns During the exhaust stroke this air cushion provides a braking effect on the pistons as the exhaust valves are then opened The higher the engine speed during the exhaust braking the greater the braking effect SE Sf y ate lay fl 4 P Fig 11 Exhaust pressure governor Bi Design and Function 12006953 Fig 10 Switch for engine
25. governor operates using two dif ferent pressures e When the exhaust pressure governor is activated during starting and keeping the engine warm the control valve provides a control pressure of approxi mately 200 kPa 29 psi e When the exhaust pressure governor is activated for engine braking the control valve provides a control pressure of approximately 750 kPa 110 psi D12A The D12A is provided with two solenoid valves one for controlling the starting and engine warming pressure and one for controlling the pressure for engine braking Both solenoid valves are located in a bracket on the cylinder head D12B The D12B is provided with an EPG control valve that controls both the starting and engine warming pressure and the pressure for engine braking The valve is located at the lower rear edge on the right hand side of the cylin der block The EPG control valve on the D12B replaces the two solenoid valves on the D12A to perform the same function 22 Fig 23 EPG control valve D12B Design and Function W2002624 Group 25 Intake and Exhaust System Air Restriction Indicator There are several types of restriction indicators which can be mounted in certain locations such as on the air cleaner duct or on above the instrument panel The air restriction indicator mounted on the instrument panel permits continuous monitoring of the gauge When either the flag or piston type restriction gauge is mounted dire
26. installing a new turbocharger pre lubricate the bearing system This will ensure adequate lubrication of the turbocharger at start up Install a new gasket and install the new tur bocharger 3 Apply sealant to the shutter housing sealing surface and install the housing to the turbocharger Mate the shutter housing flange with the heel of the tur bocharger Retighten the clamp 4 Connect the air line to the exhaust pressure governor 5 Install the turbocharger oil delivery pipe using new seals Note Be sure to remove the delivery oil plug if used to run the engine with out the turbocharger 6 Install the turbocharger oil return pipe to the cylinder block using a new seal Do not attach the oil return pipe to the turbocharger at this time 7 Install the charge air pipe into the tur bocharger using new sealing rings Attach the charge air pipe 33 Group 25 Intake and Exhaust System 8 Reconnect the air cleaner hose to the turbocharger 9 Attach the turbocharger oil return pipe using new seals 10 Apply parking brake and place shift lever in neutral Start the engine and check for proper operation and leaks 2516 03 04 01 Exhaust Manifold Gasket s Replacement Turbocharger Removed AN DANGER Before working on a vehicle set the parking brakes place the transmission in neutral and block the wheels Failure to do so can result in unexpected vehicle movement and can cause serious personal in
27. is used during starting and warm up When used for engine braking the exhaust pressure governor is controlled by a single two position switch if the engine is equipped with an ex haust brake only and by dual two position switches if the engine is equipped with a Volvo Engine Brake or VEB both exhaust brake and compression brake Engines with Exhaust Brake Only Two position switch ON OFF With the switch in the ON position the exhaust pressure governor is activated by a control pressure of approx 750 kPa 110 psi subject to the following conditions e Accelerator pedal fully up e Clutch pedal fully up e Engine speed above 1100 rpm e Boost pressure below 52 kPa 7 5 psi e When using cruise control and preselected road speed is exceeded by 7 km h 4 mph disengage ment at 4 km h 3 mph over preselected speed e ABS not activated continuous control Design and Function 72006948 Fig 17 Exhaust pressure governor EPG EXHAUST BRAKE ON W2000731 Fig 18 Exhaust brake switch for WX WG and AC W3001324 Fig 19 Exhaust brake switch for VN VHD Group 25 Intake and Exhaust System Engines with VEB When the engine brake ON OFF switch is in the ON po sition the engine brake is activated according to the position of the engine brake HI LO switch With the HI LO switch in the LO position only the ex haust pressure governor is activated and is subject to the same conditions as for engin
28. iver s seat in the cab Note Secure the hose so that it does not contact any moving parts 2 The measurement should be carried out e with a fully loaded vehicle e driving up an incline at full accel eration full load e while engine revs rpm slowly pass the speed specified for boost pressure Note For a reliable result engine load must be maintained long enough for the pressure to stabilize Boost pres sure specifications at 28 3 r s 1700 rpm e VE D12 370 125 170 kPa 18 24 7 psi e VE D12 415 145 175 kPa 21 25 4 psi 3 21 3 psi 1 5 kp cm o gt gt E ZS 5 gt 14 2 psi 1 0 kp cm 8 9 psi 0 7 kp om 85 psi 0 6 kp om 21 psi 0 5 kp em 71 psi 0 5 kp cm Cc 4 F 14 F 32F 50 F 68 F aert 104 F 20 C 10 C oC 10 C 20 C 30 C 40 C W2000737 Boost pressure at various temperatures A measured boost pressure B correction curves C intake air temperature The specifications state engine speed and boost pressure at 20 C 68 F If reading at any other temperature use the chart above to correct the resulting boost pressure Example A pressure of 80 kPa 12 psi mea sured at 10 C 14 F is equivalent to about 70 kPa 10 psi 20 C 68 F That is pressure drops as tempera ture rises If boost pressure does not reach spec ified levels check the following e pro
29. n and Function T2006949 Fig 28 Turbocharger Group 25 Intake and Exhaust System Design and Function Exhaust Manifold New design of exhaust manifold sections New design Old design W2002222 Fig 29 Manifold designs Description New design P N Qty Old design P N Qty Side section 3964707 2 1547521 2 Middle section 3964708 1 1547520 1 Complete 3964706 1 1677205 1 Improved gasket W2002223 Fig 30 Gasket Note The gaskets are marked MANIFOLD SIDE to aid in installation 25 Group 25 Intake and Exhaust System Design and Function Tightening Sequence Old Style Manifold 1 2 1 2 A 2 1 2 1 3 43 42 24 34 3 New Style Manifold 72012896 21 19 17 15 3 1 4 6 7 9 11 13 H A A SES e 20 22 16 18 2 5 10 8 14 12 W2002224 26 Group 25 Intake and Exhaust System Troubleshooting Air Restriction Indicator Checking Low restriction readings may be difficult to identify They can result from a damaged element gasket ruptured element incorrectly installed element or a leak in the en gine air intake ducts and piping When servicing the air cleaner make sure to check for these A water manome ter may also be used to check for service A maximum of 25 in of water 20 in of water measured at air cleaner body outlet is the limit of element service and indicates a need for replacement On turbocharged engines connect the manometer to the air intak
30. ng compression brak ing The rocker arm is held in its position against the valve bridge with the help of a spring tab 1 The valve clearance is greater than that on an engine without a compression brake because the induction and decompression lobes must not open the exhaust valves while the engine is in normal operating mode compres sion brake not activated Valve adjustment is carried out with shims which are placed on the valve bridge Note A maximum of two shims are allowed to obtain proper valve clearance Non Return Valve The engine brake has a non return valve consisting of a plunger 1 spring 2 and a ball 3 in the rocker arm When oil from the rocker arm shaft enters the valve the movement of the plunger is determined by the spring force and the oil pressure When the oil pressure is low approximately 100 kPa 14 5 psi the control valve is in its normal engine oper ating position the plunger 1 will not move out of its rest position because the oil pressure is not sufficient to overcome the spring force The plunger pin prevents the ball 3 from entering the seating area and the oil can then flow freely through the valve in both directions When the control valve takes up the position for com pression braking the oil pressure increases to the non return valve The spring force in the non return valve is such that when the oil pressure exceeds approxi mately 200 kPa 29 psi the spring force
31. ous personal in jury or death HOT ENGINE Keep yourself and your test equipment clear of all moving parts or hot engine parts and or fluids A hot engine and or fluids can cause burns or can permanently damage test equipment When removing and installing the intake manifold on engines equipped with VEB keep the work area as clean as possible to prevent impurities from entering the oil system This also applies to the compression brake oil delivery pipe between the cylinder block and intake manifold Group 25 Intake and Exhaust System W2000732 Fig 35 Replacing intake manifold gasket Removal 1 Remove the plastic ties from the elec tric cables under the intake manifold Disconnect the terminals from the sen sors for the charge air pressure and the charge air temperature on the in take manifold 2 Remove the boost pressure gauge connection from the intake manifold 3 Remove the bolt for the pre heater or the spacer from the fan shroud bracket Remove the pre heater or the spacer from the intake manifold and set aside 4 Loosen the alternator drive belt and re move the nut for the gear lever bracket Remove the alternator Service Procedures W2000733 Fig 36 Replacing intake manifold gasket Remove the intake manifold bolts and carefully tap the manifold loose using a plastic headed mallet 6 Clean the sealing surfaces of the in take manifold and the cylinder head Install a ne
32. perly tightened bolts on intake and exhaust manifolds e exhaust brake e backpressure in exhaust system e air cleaner element e fuel pressure 41 Group 25 Intake and Exhaust System Exhaust Backpressure Checking Pressure gauge Of indicating or U tube type graded to 24 kPa or 2 440 mm water column 3 5 psi and equipped with damper Steel pipe About 200 mm 8 in long and able to con nect to a union Union The union must be brazed onto the exhaust pipe as shown Then drill a 1 5 2 0 mm 0 06 0 08 in hole through the center of the union and the side of the exhaust pipe Hose The hose is installed between the pressure gauge and steel pipe and must be long enough for the gauge to be read inside the cab Pressure Testing Outlet Location The pressure testing fitting should be located on as straight a section of the pipe as possible two thirds after and one third before a bend in the pipe The test fitting must not be located on an outer or inner bend of the exhaust pipe Backpressure Measuring Techniques Using a chassis dynamometer is the best way to mea sure backpressure If such equipment is not available the vehicle can be driven up a long hill The accelerator pedal must be kept fully floored with the vehicle acceler ating up the hill until the engine reaches specified rpm Note the highest backpressure reading and compare it with specifications After the test make sure to block off the union
33. pres sure gauge to be considered reliable the pressure reading must not drop during a period of two minutes 39 Group 25 Intake and Exhaust System W2000735 Fig 51 Removing charge air hoses Remove the air hoses from the charge 9998288 air cooler Install connecting washer 9998289 9998288 sealing washer 9998289 and new O rings W2000736 Fig 52 Connecting pressure gauge Remove the pressure gauge reduction valve and check that the gauge read ing is 0 Connect the pressure gauge to the charge air cooler 5 Open the shut off valve and set the pressure gauge to 100 kPa 14 5 psi using the reduction valve 6 Close the shut off valve For the charge air cooler to be serviceable the pressure reading must not drop more than 50 kPa 7 psi during 30 seconds 7 If a leak is found repeat the test a few times Also check pressure gauge hoses and connections 40 Service Procedures Group 25 Intake and Exhaust System System Check System Check 2559 06 02 02 Boost Pressure Checking Note This operation number covers only the installation and removal of test equipment Special tools 9996065 9996666 12006943 Boost pressure gauge installation Clean around the plug for the boost pressure gauge on the intake mani fold Remove the plug and install union 9996666 Connect pressure gauge 9996065 to the 9996666 union Make sure the pressure gauge hose is long enough to reach the dr
34. r preceded by 999 for exam ple 9992610 W0000406 9992610 Drift for overhauling exhaust pressure 9998225 Hollow drift for overhauling exhaust governor pressure governor 9996065 Gauge for checking boost pressure 9998246 Drift for overhauling exhaust pressure 9996666 Union for checking boost pressure SE 9996662 Pressure gauge 9998288 Connecting washer for leakage test of charge air cooler 9996831 Vacuum gauge for checking pressure drop indicator 9998289 Sealing washer for leakage test of charge air cooler Group 25 Intake and Exhaust System Tools Special Equipment Like the special tools the following are available from the parts department of Volvo Trucks North America Inc When requesting tools provide the appropriate part num ber WO0001840 1159794 Torque wrench 10 100 Nm 7 73 ft lb W0001841 1159795 Torque wrench 40 340 Nm 30 250 ft lb WO0001842 1159796 Torque wrench 150 800 Nm 110 590 ft lb Group 25 Intake and Exhaust System Design and Function Intake and Exhaust System Preheater Selected versions of the D12 are equipped with a pre heater lts purpose is to warm air in the intake manifold when starting the engine This heated air eases starting at very low temperatures and reduces engine smoking when starting a cold engine The following conditions are required to engage the preheater e The parking brake must be applied e The power take off must not be engaged The preh
35. shift lever is in neutral 2 Tilt hood 3 W2000940 Fig 31 Removing the endcap WG AC Remove the endcap by removing the hardware depending on the type of endcap that attaches the endcap to the air filter Note The type of hardware used to hold the endcap varies depending on the style of air cleaner and air cleaner assembly W2002051 Fig 32 Removing the air filter VN VHD and VNM Remove the air filter 29 Group 25 Intake and Exhaust System Fig 33 Remove the air filter WG AC Remove the element from the canister If the element is held by a wing nut remove the wing nut before removing the element Installation 6 Clean and inspect the inside of the housing and endcap 7 Lubricate the rear seal on the new fil ter with Vaseline or the like 8 Install the new filter Make sure that it is correctly positioned in the filter housing 30 Service Procedures W2000746 Fig 34 Endcap reinstall Reinstall the endcap and attach using 24 2 Nm the necessary hardware Tighten to a 18 2 ft lb torque of 24 2 Nm 18 2 ft lb Note Refer to the label attached in side the endcap on some models 2512 03 02 01 Intake Manifold Gasket s Re placement AN DANGER Before working on a vehicle set the parking brakes place the transmission in neutral and block the wheels Failure to do so can result in unexpected vehicle movement and can cause seri
36. stem 2 Remove the bolts holding the charge air pipe to the mounting bracket Pull the charge air pipe off the tur bocharger 3 Remove the air line from the exhaust pressure governor 4 Remove the turbocharger oil delivery and return pipes Install a protective plug into the connection for the oil de livery pipe on the oil filter bracket 5 Loosen the clamp between the tur bocharger and the shutter housing Remove the shutter housing from the turbocharger 6 Remove the nuts and lift the tur bocharger off 7 Clean the sealing surfaces of the ex haust manifold shutter housing and oil pipe connections Installation W2000739 Fig 39 Turbocharger assembly Gasket Clamp Air line Oil delivery pipe Oil return pipe do e D E Service Procedures 1 Before installing the new turbocharger check the engine oil and change the oil filters if required Then run the en gine a few minutes before installing the new turbocharger When running the engine without a turbocharger be sure to plug the oil delivery line As a precaution to prevent the oil from en tering the new turbocharger a strainer can be temporarily installed into the oil entry point Then run the engine for at least a half hour Note After this test remove the strainer to prevent strainer blockage that may occur if the oil system is not properly maintained 2 Before
37. w gasket Installation 1 Install a new seal on the compression brake oil duct 2 Apply a 2 mm 1 16 in bead of 2mm sealant to the intake manifold The 1 16 in manifold must be installed and tight ened within 20 minutes after applying sealant Note Do not allow the sealant to enter the oil duct of the compression brake 31 Group 25 Intake and Exhaust System W2000734 Fig 37 Replacing intake manifold gasket Adjust the alternator A C refrigerant compressor drive belt tension if so equipped 4 Install the pre heater if equipped or the spacer using new gaskets and bolt the mounting to the fan shroud 5 Install the boost air gauge connections to the intake manifold 6 Reconnect the terminals to the sen sors for the boost air pressure and the boost air temperature on the intake manifold Tie the electrical cables 2551 03 02 02 Turbocharger Replacement AN DANGER Before working on a vehicle set the parking brakes place the transmission in neutral and block the wheels Failure to do so can result in unexpected vehicle movement and can cause serious personal in jury or death HOT ENGINE Keep yourself and your test equipment clear of all moving parts or hot engine parts and or fluids A hot engine and or fluids can cause burns or can permanently damage test equipment Service Procedures W2000943 Fig 38 Turbocharger assembly n a
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