DDFP SERIES ENGINES FOR FIRE PUMP APPLICATIONS MP-4. Manual - part 6

DDFP

SECTION 3.2

Page 16

AIR INTAKE AND EXHAUST SYSTEM

The air, entering the blo wer from the air cleaner , is picked

up by the blo wer rotor lobes and carried to the dischar ge

side of the blower as indicated by the arro ws in Figure 1 &

2, Page 1.  The continuous dischar ge of fresh air from the

blower enters the air chamber of the c

ylinder block and

sweeps through the intake ports of the cylinder liners.

The angle of the ports in the c ylinder liners creates a uni-

form swirling motion to the intak e air as it enters the c ylin-

ders.  This motion persists throughout the compr

ession

The air cleaner manufacturer recommends the following:

1. On engines using dry elements, replace the air cleaner

element.

2. On engines with pre-oiled elements, service with a spe-

cial oil. These elements can be serviced or replaced. Part

number is shown in the parts section of this manual.

3. When servicing the element is not practical, you can im-

prove filter efficiency by re-spraying with oil.

NOTE:

Do not attempt this while engine is running.

NOTE:

Do not over oil.

AIR INTAKE OPERATION

In the scavenging process employed in the engines, a charge

of air is forced into the c ylinders by the blo wer and thor-

oughly sweeps out all of the b

urned gases through the

exhaust v alves.   This air also helps to cool the inter

nal

engine parts, particularly the e xhaust valves. At the be gin-

ning of the compression strok e, therefore, each cylinder is

filled with fresh, clean air which provides for efficient com-

bustion.

AIR CLEANER

The air cleaner used on DDFP engines is either a dry type or

the reusable type. Should a situation occur where the air

cleaner becomes plugged with dirt (starving the engine for

air), low power and heavy black smoke will be the result; the

air cleaner should be serviced immediately.

CAUTION:

Do not attempt to remo ve the air cleaner

while an engine is running nor run the engine

while the air cleaner is of f. Exposed turbo-

charger could cause se vere injury to person-

nel and major internal engine damage could

occur should an y foreign matter be dra wn

into the engine.

SECTION 3.2

DDFP

AIR FILTER SERVICE INSTRUCTIONS

Figure 1 - Air Filter Service Instructions

Page 17

DDFP

AIR BOX DRAINS

During normal engine operation,

water v apor from the

intake air, as well as a slight amount of fuel and lubricating

oil fumes, condenses and settles on the bottom of the air

box. This condensation is remo ved by the air box pressure

through air box drain tubes mounted on the side of the cylin-

der block.

SECTION 3.2

CRANKCASE VENTILATION

Harmful vapors which may form within the engine are re-

moved from the crankcase, gear train, and injector compart-

ments by a continuous, pressurized ventilation system.

Figure 2 - Crankcase Ventilation

I-53

V71 or V-92

I-71

Liquid accumulation in the air box will result if a drain tube

becomes plugged. Remo ve the drain tubes and connectors

from the c ylinder block and clean them thoroughly when

necessary.

rocker arm compartment. Here it is e xpelled through a vent

pipe attached to the rock er cover breather assembly. Turbo

charged I-71 engines additionally use a breather attached to

the front left side of the c ylinder block. Figure 2 sho ws the

vent system for each engine series.

A slight pressure is maintained within the engine crankcase

and injector compartment.  This crankcase pressure and re-

sulting ventilation is accomplished by the air seepage past

the piston rings sweeping up through the flywheel housing

and/or the balance weight co ver into the v alve and injector

Page 18

NOTE:

Exhaust back pressure, air inlet restriction and

crankcase pressure limits are listed for each

DDFP Model in Technical Data Section 5. These

limits are not to be e xceeded. To properly check

these limits, the engine must be producing maxi-

mum required horsepower.

While the engine is running inspect e xhaust pipe outlet out-

side of the pump room itself for en vironmental hazards such

as excessive smoke conditions. The following could be used

as a guide for general engine operating conditions.
1. Blue Smoke — Possible engine oil consumption - too 

many areas to list for possibilities.

2. White Smoke — Possibility of water in cylinders

Source — Possible w ater in fuel or internal engine prob-

lem.

Should any of these or any other conditions be found, contact

your local DDC Distrib utor/Dealer for assistance. Check

condition of the air inlet system ducting, clamp tightness hose

condition.

Yearly

Clean and re-oil the air cleaner element per the manufacturers

directions. Each engine is shipped with the cleaning instruc-

tions. Refer to Figure 1, page 17.
Check crankcase v entilation tube for proper operation by

making a visual inspection while engine is running.

EXHAUST OPERATION

Internal combustion engines con vert fuel ener gy into both

useful w ork and w asted heat.  The useful w ork is the fly-

wheel rotation that dri ves the pump.  The w asted heat

involves the engine water cooling system, radiated heat and

the exhaust gases.  Approximately 2/

3

of the fuel ener gy is

wasted. Critical re view must be made of these systems to

assure that the engine delivers the useful power required and

maintains the engine within the operating parameters estab-

lished by the engine manufacturer.

The exhaust system is critical to the proper engine perform-

ance. When initially installed, consideration must be gi ven

to the exhaust gas flow requirements, the exhaust tempera-

tures and the e xhaust back-pressure limitations of the spe-

cific engine. Generally , N engines can tolerate a higher

exhaust pressure than T engines. Refer to Section 5 for spe-

cific engine model and operating speed back-pressure limi-

tations. All the components in an exhaust system contribute

to the back-pressure determination including the fle

x

exhaust section, muffler, exhaust piping and its conf igura-

tion. In addition to providing engine exhaust data and back-

pressure limitations, Clarke of fers a service to installers,

through the local Pump OEM Dealer , for making recom-

mendations on e xhaust system sizing for specif ic installa-

tions.

If the exhaust system should become restricted, the hot ex-

haust gases cannot escape from the engine.  This condition

would cause a loss of po wer, extreme internal engine heat,

and very high e xhaust gas temperatures.  These conditions

can and will cause internal cylinder damage and a reduction

of engine life.

Some engines are turbocharged (T). Turbochargers increase

the air flo w into the engine c ylinder and permit increased

horsepower by burning more fuel than is possible in a natu-

rally aspirated (N) engine.  Turbochargers enhance the ef fi-

ciencies of engines and add power to a similar displacement

(N) engine.

Basically, turbochargers are maintenance free. Ho wever,

should any exhaust manifold studs or bolts break or come

loose, engine exhaust gases can start leaking into the pump

room. Under these conditions, the engine should be attend-

ed to immediately . First indications of an e

xhaust leak

would be the smell of diesel exhaust and possible eye irrita-

tion. Unless f ire pump maintenance personnel are well

versed in a repair of turbochar gers and e xhaust systems,

contact your local Distributor/Dealer for assistance.

MAINTENANCE AND SERVICE PROCEDURES

Weekly

Prior to each maintenance run mak e a visual check of the

exhaust system to v erify condition of piping and muf fler (if

used). Investigate thoroughly any areas that w ould appear to

have rusty conditions such as rain w ater running do wn pipe

and getting inside the engine. Se vere internal engine damage

could occur.

Inspect the engine air cleaner for dirt b uildup or damage.

During actual maintenance run check engine crankcase venti-

lation tube for excessive blow-by or pressure.

6 Months

Inspect exhaust system for leaks or plugging,if any are found,

repair immediately. Inspect and tighten if necessary e xhaust

manifold, turbo mount (if equipped) and piping bolts/n uts.

NFPA 37 requirements are to ha ve the e xhaust system co v-

ered with high temperature insulation for personnel protec-

tion. Inspect the insulations condition for any deterioration or

looseness, repair as necessary. 

Exhaust system back pressure limits are not to be e xceeded.

SECTION 3.2

DDFP

Page 19