Porsche 912E 76 Service Information

The

Porsc

he

912

E

..

.

The techni

ca

l

spec

ificat ions are

as

follows:

Capacity:

1971 cm

3

Stroke:

71

mm

Bore:

91

mm

Horse power:

developed at:

Torque:

develo

ped

at:

86

hp/64

4900 rpm

98

Ibft/133

4000 rpm

.

..

is

equipped

with

..

.

. . . a

2

Itr

., 4 cylinder engine (similar to that in the

Type

This

motor

has

been

fitted

with

the electronically controlled AFC fuel injection thermal reactors

and

exhaust

gas

recirculation .

.

· . . a 5

speed

transmission

(based

on transmission

type

915)

with

modified transmission ratio

and a newly designed clutch operation mechanism.

·

..

a like the 911, a dual-circuit brake system,

disks brakes

without

"inner

ventilation"

.

·

bodywork

similar

to

the 911

but

with

permanently

fixed rear side windows as we

ll

as

other

minor

changes.

2

10

ENGINE

CRANK

CASE,

CYLINDERS,

ENGINE

MOUNTS

The crank

case

and the cylinders

are

the

same

as

in the engine

type

914/2

.0 Itr.

The following

is

new:

The engine mount.

It

consists

of

a swung steel bar which

is

secured

to

the

motor

in the

same

way

as

in the 914.

The mounting points on the

chassis

were moved outwards

to

the wheel wells however.

Warning:

installing the

motor

mount, note that the casted in part number (arrow)

is

pointing toward

t

he

rear.

3

13

CRANK

SHAFT

DRIVE/PISTONS

All

parts

of

the crank shaft drive

are

the

same

as

in the basic motor.

An

additional fan-belt

pulley

is

fitted

to

drive the secondary air pump. It

IS

secured to the

front

of

the air intake housing

by

means

of

a

thr

ee-armed block and

is

driven by

means

of

a shaft

from

the center

of

the cooling fan .

19

COOLI

NG

The

eng

ine sh

ee

tmetal w

as

changed

to

conform

to

the

911

engine compartment configuration .

4

20

FUEL

SUPPL

V

The

912

E

is

fitted

with

an

80 Itr. (inc!. 8 Itr. reserve) fuel tank.

The fu

el

pump

is mounted on the

front

ax le aux il iary mount.

The fuel

filter

is the

same

as

in the CIS injection

It

is

secured

to

the l

eft

-h

and wheel well in the

engine compartment

1

1.

) Fuel

tank

2.)

Fuel

pump

3.

) Fuel

filter

4.)

Pressure

regulator

5

.)

Injection

valv

es

6.)

Cold start

valve

5

24

EL

ECTRONIC

F

UEL

INJECTION

-

AFC

The Porsc

he

912 E

is

equipped

with

a

motor

that

has

a air

flow

controlled electronic fuel injection .

Before we describe this

unit

in detail, a few words about the accelerator cable.

The

accel

era

tor

cable

is

in

two

parts. The connector (arrow)

is

located

within

the engine compart-

ment behind the rear panel

and

is

accessible when the cover

to

the guide channel

is

removed.

Construction

and

funct

ion of the

ATC

injection

The component parts

1 Fuel Tank

2 Fuel Pump

3 Fuel Filter

4 Cold Start Valve

6 5 Fuel Injector

6

Pressure

Regulator

7

Auxiliary

Air

Regulator

8

Throttle

Switch

9

Air

Filter

10

Temperature

Sensor

II

11

Battery

12

Ignition Switch

A Int

ak

e-air

Sensor

B

Throttle

valve

C

Air

Sensor

Flap

o

Co

ntrol Unit

Principles

of

Operation

The amount

of

fuel

that

is

to

be

used

is

determined

by

the vo lume

of

intake air

and

the

speed

of

the

motor.

The injector sequence

is

determi

ne

d

by

th

e igni

tion

dis

tr

ibu

tor

breaker points.

The fuel required

for

cold starting

is

injected by the electro-magnetic cold start valve.

Warm-up

en

richment

of

t

he

fuel

mixture

is

via t he

au

xiliary air regulator in conjunction

with

the

temperature s

ens

or I in the in take-air

Se

n

so

r housing and t

he

temperature sensor II in the cylinder

head.

Fuel mixture enrichme

nt

for

full

load condi tio

ns

is

by

me

a

ns

of

a

throttle

switch.

6

2

.

24

ELECTRONIC

FUEL

INJECTION

-

AFC

Description

Intake-Air

Sensor

The intake-air sensor

is

located

in

the engine compartment at the right-hand side between the air

filter

and the

throttle

housing (L) .

Construction

Aluminum

housing (A)

with

Bye-pass channel (5)

and

Adjustment

screw (6)

Air

sensor flap (1)

with

Back pressure valve (8)

and Damping vane (2)

Damping chamber (7)

Return spring (9)

Potentiometer

(B)

with

Pump contacts

(C)

Temp

era

ture sensor I (D)

Operation

The volume

of

air that the

motor

can

draw in

is

determined

by

the position

of

the thro

ttle

valve.

The resultant air

flow

causes

the sensor flap

to

deflect against the return spring. T

he

flap deflection

is

transmitted via a shaft

to

the potentiometer which supplies a specific voltage

to

the con

trol

unit. The

temperature sensor I

is

connected

to

the potentiometer and influences the control signal volta

ge.

The injector which

is

activated by the control

unit

injects

an

exact amount

of

fuel appropriate

to

the

volume

of

intake-air.

The damping vane

is

designed

to

minimize sensor flap hunting. The

function

is

as

follows:

with

deflection

of

the flap the damping vane

is

forced

into

the damping chamber. The resultant compressed

air

within

the chamber

can

escape

only

through the

release

slit

(S)

. Sudden movements

and

hunting

is

thereby reduced.

A fraction

of

the air intake

is

detoured around the sensor flap via the bye-pass channel. The fuel-air

mixture

for

idle

can

be

set

by

means

of

the adjusting screw (6).

A pump contact

is

located

within

the potentiometer.

When

the sensor flap

is

deflected open the pump

contact

is

closed and the fuel pump started .

Prob l

em

condition:

Motor

does

not

start; starting

dif

ficulties;

low

efficiency.

Troubleshooting :

Remove the plug connected

to

the potentiometer on the intake-air sensor. Connect

an

ohm meter

between the contacts 6 and

9.

value: 200

to

400

Mea

sure between contacts 7

an

d 8.

Nominal value: 120

to

200

7

\

4

~

---

.

---.------.

"

-,

24

ELECTRONIC

FUEL

INJECTION

-

AFC

Throttle Switch

This switch provides the control

unit

with

necessary

information

for

mixture

enrichment and

full

load

cond itions.

It

is

not

necessary

to

adjust this switch.

Problem

condition:

Low

engine power

Troubleshooting:

Disconnect the wires

from

the switch and connect

an

ohm meter between contacts 3 and 18.

Slowly

open the

throttle

valve. The resistance must change

from

00

to

0

Ignition Distributor

The ignition

distributor

provides the control

unit

with

information

concerni

ng

the

speed

of

the

engine (rpm) and sequen

ce

for

activating the fuel injectors.

Operation

In addition

to

de

livering impulses

to

the ignition coil,

the contact breaker points

also

supply impul

ses

to

th

e control unit.

Each

impulse (1)

is

converted

to

a

squ

are wa

ve

(2)

within

the

control

unit

. These

sq

uare wave impulses are then presented to a gate (3)

which provides a single

pu

Ise

output

for

each

sequ

ence

of

four

input

pu

Ises

which are the

resu

It

of

t

wo

re

volutions

of

the

motor

crank shaft. That

is,

f

ollowi

ng

each

revolu

tion

of

the crank shaft all

fo

ur

fuel injectors

hav

e received

an

ac

tivat

ing

impulse (5

).

Thus the fuel injectors inject a de

fin

ite

amount

of

fuel independent

from

the position

of

th

e air sensor flap. The injected fuel

is

always half

of

the amount necessary

for

the correct fuel

mix

ture. Si

nce

the crank shaft turns

tw

i

ce

for

each

cycle,

two

injector sequences

are

put

into

operation

thus

each

cylinder receives the

full

amount

of

fuel

for

each

firing stroke.

o

Zyl. 1

Zy

l.4

Zyl. 3

Zyl.2

1 breaker

im

pulses

-

--t-

2 imp

ul

se

shaper

3 frequency

d

ivid

er

4 air

flow

senso

r

fla

p position

(pot

entiom

eter)

'5

injection i

mpul

(duration

of

injection)

su

ct

ion

compressi

on

ign

it

ion

exhaust

o crankshaft angle

360

7

20

·

I

:

control

unit

(e

lectronic)

8

. .

24

ELECTRONIC

FUEL

INJECTION

-

AFC

Temperature Sensor I

The temperature sensor I

is

located in the intake air sensor housing

and

permanentely installed.

It

can

not

be

replaced separately. Its

function

is

to

measure the temperature

of

the intake air and

provide the

control

unit

with

the appropriate

information

.

Troubleshooting:

Simi lar

to

the intake-air sensor.

Temperature Sensor

II

This sensor

is

located in the cylinder head.

It

provides the control

unit

with

information

concerning

engine temperature

and

thus about the starting and warm-up enrichment.

Problem condition: the

motor

does

not

start; warm starting difficulties;

motor

starts

but

stops again

almost at once; fuel consumption

too

high;

CO

value

is

too

high in slow running.

Troubleshooti

ng

:

Connect

an

ohm meter between temperature sensor II

and

ground.

Nominal value at

20°C/68°F

motor

and ambient temperature:

1.5

to

2 the

motor

temperature

is

above

80°CI176°F

the value must

be

less

than

300

9

24

ELECTRONIC

FUEL

INJECTION

-

AFC

Cont

ro

l Unit

The control u

nit

is

located in the engine compartment

within

a cavity welded

to

the right-hand wheel

well.

The contro l

unit

proc

es

s

es

information

concerning

the

fo

llowing:

Volume

of

intake air

Temperature

of

i

nt

ake a

ir

Motor

rpm

Motor

temperatu

re

Intake air sensor deflec

tion

(fu ll load)

It

determi

nes

an

d c

ontro

Is

th

e injection sequence and

duration.

The electronic con

tro

l unit

is

composed

of

printed

circuits and

int

egrated circu

it

components.

It

is

fitted

wi

th app

rox

imately 80 components.

The printed ci rcu

it

board

is

secured

to

the

control

unit

and

presse

d in

to

the socket

until

a spring

snaps

into

place.

Code explanation:

A Control un

it

1 Control mul

ti

vibrator

1a Impul

se

an

d rpm divider

2

Multipl

ier st

age

2a

Warm-up enrich ment

3

Output

st

a

ge

4 Fuel injector

5

Series

resistor

I Control voltage from intake-air

se

ns

or

la Control impulse from

distributor

contact breaker

point

s

II Control signal

from

throttle

switch

Iia Control voltage

from

starter swit

ch/

temperature sensor II

10

-

24

ELECTRONIC

FUEL

INJECTION

-

AFC

Fuel Injector

The volume

of

injected fuel

is

determined by the

length

of

time the injector

is

open (i.

e.

the time

of

the impulse

from

the control

unit).

The injector

is

connected

to

+ via the resistor (R).

(The contro l signal

from

the control

unit

is

of

negative potential.)

Injection Sequence

All

injectors

are

activated simultaneously, once

for

every crank shaft revolution.

Note:

The plug and socket assembly

is

so

arranged that

it

can

not

be

inadvertanly connected

to

an

injector

of

the

MPC

injection.

Pressure Regulator

The pressure regulator regulates the pressure

of

the

fuel in the ring supply line independent

of

the

pressure in the vacuum line.

The spri

ng

chamber

of

the

pressu

re

regu

lator

is

connected to the intake air

distributor

via a

hose

.

Operation

By using this configuration the pressure

of

the fuel

is adj usted independent

of

the vacuum in the intake

air

distributor.

For example

High vacuum in the intake air

distributor

(idle operation) -

low

fuel pressure. L

ow

vacuum in the

intake air

distributor

(full load) - high fuel pressure.

This way, the difference between fuel pressure and intake air

distributor

pressure always remains

the

same

for

all load conditions

of

the engine.

Troubleshooting :

Connect a

pr

essur

e

gauge

into

the ring supply line. Disconnect the vacuum

hose

from

th

e pressure

reg

ulator. Start the

motor

.

Nominal value: 2.5 bar (36.75

psi

approx.)

Reconnect the

hose

the fuel pressure must now

be

lower.

11

24

ELECTRONIC

FUEL

INJECTION

-

AFC

Auxiliary Air Regulator

The engine requires during the warm-up

phase

a

richer

mixture

. The increased volume

is

determined

by

the

control

unit

(signal

from

temperature sensor

II). The additional volume

of

air required

for

this

purpose

is

regulated

by

the

auxiliary

air regulator

and detoured around the

throttle

valve

into

the

intake air distributor.

Construction

The

auxiliary

air regulator consists

of

a slide valve

and a bi-metal spring which

is

enclosed

by

an

electrical heating coil.

Operation

If

the engine

is

cold, the auxiliary air slide valve

is

fully

open. When the ignition switch

is

turned on

the heating coil starts

to

warm up. With increase

in temperature the bi-metal spring becomes weaker

and

the slide valve slowly shuts

off

the air intake.

Troubleshooting:

Electrical : Disconnect the plug

to

the auxiliary

air regulator. Connect

an

ohm meter.

Nominal value: approx. 30.

Mechanical : Remove

hose

from

the intake manifold

and

throttle

housing.

Blow

air

thru

from

one side.

If

the

motor

is

cold

the air must

flow

freely. Switch on

the ignition, continue

to

blow

air

thru

and observe that the air

flow

becomes

restricted

with

increase in temperature.

.b

-

12

t

24

ELECTRONIC

FUEL

INJECTION

-

AFC

Troubleshooting:

Thermo

switch: Engine temperature under

10°C/

50°F.

Remove the plug

from

the

cold start valve and connect a

test lamp. Disconnect the

wire

from

contact

1 on the

ignition

coil. Operate the starter

motor

:

the test lamp must

initially

be

bright

and then

visibly

darker

within

not

less

than

11

seconds.

Cold start valve : Connect a pressure gauge

to

the

ring

supply

line.

Operate the starter

motor

in

order

to

reduce the fuel pressure.

Remove the plug

from

the cold

start valve. Conne

ct

the

cold

start valve

by

means

of

extra

wi

res

to

ground and

contact

15

on the

ignition

coil.

Turn

on the

ignition

switch

--

the fuel pressure

must fall.

Cold Starting Valve

The cold starting valve

is

located in intake air

distributor

and

is

activated

by

a

thermo

time

switch

which

is

located adjacent

to

the intake air

distributor.

Here are a

few

tips concernig

trouble

free

operation

of

engines equipped

with

AFC

injection

.

All

ai

r lines and hos

es

and the intake

-ai

r sensor must be absolutely air

tight

. The sensor flap must be

able to move

fr

e

ely

over its entire range and

not

stick at any

point.

All

e

le

ctrical connections must

be

tight

and free

of

corrosion .

Plug and socket

color

code: Fuel

injector

:

white

Cold start valve:

blue

Thermo

time

switch :

brown

Intake-air sensor:

black

When the vacuum line

is

disconnected, the fuel

pr

ess

ure must be

about

36

psi.

Ignition

timing

and vaive

adjustment

must

be

correct.

For

idle and

CO

adjustment

:

Idle

is

by

adjusting the screw on t

he

throttl

e housing.

Nom

in

al

v

al

u

e:

925

± 50

rpm

The CO value

is

fa

cto

ry

adjusted

by

me

ans

of

the bye-p

ass

a

dj

ustme

nt

screw in the intake-air sensor

housing.

The

posi

tion

of

this

screw should be altered o

nly

when

the

no

minal value

of

0.5 - 1.2 %

CO

ca

n

no

t

be

obtained inspite

perfect

wo

rkin

g order

of

th

e engine.

The CO-adjustment

sc

rew

is

covered

by

a plug. (Part No.

923.606

.991 .01)

Pl

ug col

or

code:

Bl

ack: Bo

sc

h setting

Blue: Pr

oduction

setting

Red: Service s

etti

ng

13

CIRCUIT

DIAGRAM

FOR

THE

AFC

INJECTION

1

Multipo

le

plug

2 Ignition coil

3

Throttle

switch

4 Intake-air Sensor

5 Temperature

sensor

II

6 Cold start valve

7 Thermo

ti

me

switch

8 Fuel pump

9 Ground connection (Gnd)

10 Double relay

11

Auxiliary

air regulator

12

Series

resistor

13 Battery

14 Fuel injector cyl. 1

15 Fuel injector cyl. 2

16 Fuel

injectorcyl.

3

17

Fuel injector cyl. 4

Test

Values

4.

Intake-air

Sensor

: pin 6 + 9 = 200 - 400

pin 7 + 8 = 120 - 200

pin 36 + 39 = 0

Air

sensor

flap =

00

27

+ 6 = 8 -

11

k

at

100C

(50°F)

2 - 3 k

at 20°C (68°F)

- 2 k

at

50°C (122°

F)

3.

Throttleswitch: pin 3 + 18,

throttle

open =

00

to 0

5. Temper

at

ure

sensor

II: at approx. 20°C (68°

F)

approx. 2.5

13 +

49

at approx. 80°C (176°F) below 300

6.

Cold start

valve

: pin 45 + 46 = 4

7. Thermo time switch:

below + 30°C (86°

F)

above

+ 40°C (104°

F)

G +

Gnd

25 - 40

50

- 80

Wt

Gnd

100 - 160

G + W

25 - 40 50 - 80

1

0.

Double relay :

pin85+86b=

50

- 100

12. Seriesresistor : pin 43 + Gnd. =

5-

14. -

17

. Fuel injector:

pin 14 + 41/32 + 40/33/38115 +

37

= 2 - 3

14

26

EXHAUST

SYSTEM

The

912

E engines

are

equipped

with

a secondary air injection, thermal reactors and EGR.

The

muffler

and heat exchangers

are

also new.

The secondary air injection and the thermal reactors are designed

to

reduce the

CO

and

HC

emission

in the exhaust. The purpose

of

the EGR

is

to

reduce the emission

of

nitric

oxide (NO

x

).

Secondary

Air

Injection

The air required

for

after burning the exhaust

gases

is

supplied

to

the exhaust manifold by means

of

a

motor

driven air pump.

The air

from

the pump (1)

is

pumped via a back-up

valve (2) and a

distributor

line (3)

to

the air

injection valve (4) which

is

located immediately

behind the exhaust valve. The exhaust

gas

after

burning takes place in the thermal reactor (5) .

3

15

26

EXHAUST

SYSTEM

Thermal Reactor

The thermal reactor

mainly

consists

of

two

cylinders, one inside the other, (1) and (2). Cylinder 2,

which

is

the combustion chamber,

is

provided

with

exactly defined holes (5). The outside wall

is

covered

with

an

insulating material.

-6-

4

1

-3-

Operation

The

hot

exhaust

gas

which

is

mixed

with

the secondary air enters the reactor combustion chamber (3)

via the exhaust pipe (4). The

gas

leaves

the combustion chamber via the holes

of

the inner pipe (6)

and

is

expelled

from

the reactor through the

outlet

port

(7).

Due

to

the arrangement

of

the holes in the combustion chamber the

flow

of

gas

is

slowed down.

During this time the after burning process takes place.

16

in

es

ne

26

EXHAUST

SYSTEM

Exhaust

Gas

Recirculation

(EGR)

Exhaust

gas

r

ec

irculation is designed

to

r

ed

uce the

nitri

c

oxide

emission (NO

x

)

in a particular load

range

of

the engine.

Construct

ion:

The devi

ce

co nsists

of

a diaphragm

contro

l

va

lve

(A),

exhaust

gas

(8)

with

filte

r

(C)

and a v

ac

uum

contro

l (D)

Operation

In the part-load ran

ge

the

cont

rol

va

lve diaphragm

is

lift

ed

by

the vacuum in the

control

line.

T

he

va

lve opens and fresh a

ir

is

mixed

wi

th a

fraction

of

the exhaust

ga

s.

Th

is

contro

ll

ed

"pollution"

reduc

es

the

nitric-oxide

concentration

(NO

x

)

in the exhaust

gas.

The

funct

ion of the EGR system must

be

tested every

30,000

miles. A cou

nting

mechanism

is

fitted

behind the speedometer

which

lights a warning lamp ma

rk

ed

wh

en the

30,000

mile

limit

has

been reached.

17

28

IGNITION

SYSTEM

The

912

E

motor

is

fitted

with

a battery ignition system.

Due

to

the installation

of

the secondary air injection pump, the observation hole

for

the

timing

marker

is

no longer accessible. The TDC marker (previously on the fan wheel)

is

now located on the

fan-belt

pully

(arrow).

An

angle bracket which

is

secured

to

the air intake housing

serves

as

reference

point

.

Technical Specifications: Ignition System

Firing order:

1-4-3-2

Dwell angle :

Timing:

27° before TDC at 3500 rpm

vacuum

hose

disconnected

Spark plugs:

Bosch W

175 M 30 plug

gap

0.7 mm

Beru

175114/3 L

T

he

distrib

utor

is

fitted

with

a vacuum operated advance and retard mechanism . The vacuum hose

fo

r retarding

is

green.

18

i

TECHNICAL

SPECIFICATIONS

Engine

Number

of

cylinders

Bore

Stroke

capacity (actual)

Compression ratio

Maximum

horse power rating

according

to

DI

N 70020

Net power SAE J 245

developed at :

Max

imum

torqu

e

acc

ording

to

01

N 70020

Ne

tt

torque SAE J 245

developed at :

Max

imum

rpm

Turn

off

revolutions

of

rpm li

miter

in

th

e c

ontrol

unit

Valve clearance: (engine cold)

Intake

Exhaust

En

gine weight kg/lbs

Emi

ss

ion system

F

ue

l supply

sys

tem

F

ue

l supp

ly

F

ue

l octane count requirements

El

ec

trical equipme

nt

Battery

Ba

tt

e

ry

option

al

Al

te

rnator

4

mm/in

.

94/3.70

mm/in

.

71/2.80

cm

3

/cu.in

19711120.3

7.6 : 1

HP/kW

90/66

HP/kW

86/64

rpm

4900

Kpm/Nm

141137

Ibft/Nm

98/133

rpm

4000

rpm

5500

rpm

5800 ± 100

0.

15

mm

0.20

mm

155/342

S

ec

ondary air inje

cti

o

n,

thermal reactor

and

ex

haust

gas

recirculation (EGR)

El

e

ctr

on i

ca

lly

con

troll

ed f

ue

l inj

ec

ti

on

-AFC

.

Electric pu'

mp

ROZ

91

12

V/44

A/hr.

12

V/66

A/hr

.

980

W,

70

14

V (B

osc

h)

19

TRANSMISSION

The 5

speed

transmission

923/02

is

a development

of

the transmission

type

915/44

(5

speed

trans-

mission

for

the 911) and

differs

from

it

in the

following

points :

1.

Clutch and operation

2.

Main shaft

sp

lines

3.

Ring gear and

pinion

ratio

4.

4th.

and

5th

. gear ratio

20

30

CLUTCH/CLUTCH

OPERATION

Clutch

pressure plate and disk.

The clutch

is

a single

dry

plate

clutch

of

pressed

design.

The

clutch

disk

has

24

splines,

unlik

e the 911

which

has

(SAE arrangement)

20

splin

es.

De

scr

iption

of

the pressure plate:

M

215

K Sph

D

escr

iption

of

the

clutch

disk:

215GUD

Plate pressure :

4903

- 5492 N (500 - 560 kp)

21

30

CLUTCH/CLUTCH

OPERATION

Clutch lever and cable

In order

to

obtai n a reverse movement

from

the one on the 911 model, the lever

was

moved in the

direction

of the transmission housing.

The

clut

ch cable

is

2080 ± 1.5 mm long and

has

a diameter

of

3.0 mm. The cable housing

is

secured

to one

of

the mou

nt

s on the transmission housing.

The distance of travel

for

the

lever (di

m.

A)

is

18.0 ± 1.5 mm.

Clut

ch

pe

da

l free movement

is

15 ± 5

mm

.

22

30

CLUTCH/CLUTCH

OPERATION

Adjustment

of

the lever and

fork

The lever and the

fork

must

be

correctly

located in order

to

assure

correct operation .

The dimensions are

as

follows

:

From t

he

mating surface on the transmission housing

to

the lever

is

71

mm.

;

Wit

h

out

a

lt

ering the

71

mm dimension, m

eas

ure the distance from the transmission housing

(i

n t

he

area

of

the

cl

ut

ch

cab

le

mounting

to

th

e

se

mi-circular depressi

on

for

the lever.

This dimension must

be

101

mm.

If

necessary, move the lever on

it

s

sp

lin

es.

23

30

Cl.UTCH/CLUTCH

OPERATION

Throw

out

bearing and guide

Throw

out

bearing :

The bearing

is

maintenance free and must

not

be

dismantled.

The guide

sleeve

for

the

throw

out

bearing

is

bolted

to

the transmission housing.

The main shaft oil

seal

is

held

within

the guide

sleeve

(for

ease

of

replacement

of

sea

l)

.

The

space

between transmission housing and guide

sleeve

is

sealed

by

an

O-ring.

24

34

35

SHIFT

MECHANISM/HOUSING

Transmission Mounts

Attached

to

the transmission

mount

is

a dampening material

to

reduce engine and transmission

vibrations and noise.

SHAFTS/GEARS

Main Shaft

The main shaft

is

also

provided

with

24 splines.

Gear-pair for 4th

and

5th

gear

As

previously mentioned, the transmission ratio

for

the 4th

and

5th

gear

in the transmission

unit

923/02

is

different

from that

in

the

915/44

transmission unit.

T

he

ratio differences

for

the

two

transmission units

are

as

follows :

Type

923/02

915/44

1

st

gear

11/35

i = 3.1818

11/35

2nd

gear

18/33

i = 1.8333

18/33

3rd

gear

23/29

i = 1.2609

23/29

4th

gear

26/25

i = 0.9615

26/26

i = 1.000

5th

gea

r

29/21

i = 0.7241

28/23

i = 0.8214

25

35

SHAFTS/GEARS

Ring

gear

and

pinion

The ratio

of

ring gear and pinion

is

also

different

in the

923/02

.

923/02

K : T 7 :

31

i = 4.4285

915/44

K : T

8 :

31

i = 3.

8750

Speedometer

Drive

The Type

912

E vehicles

are

equipped

with

an

electronically controlled speedometer.

Impulses

from

a magnetic disk which

is

mounted on the differential housing activate a

reed

relay.

From there the impulses

are

fed

to

the speedometer.

26

lJ

D

SPECIFICATIONS

Transmission (5

speed

transmission)

Vehicle type

Clutch

Pressure

plate

Pressure

N (kp)

Clutch disk

5

speed

manual transmission

Transmission Type

Ratio: 1st

gear

2nd

gear

3rd

gear

4th

gear

5th gear

Reverse

gear

Final drive

Final drive ratio

K/T

Limited slip differential

Slipping factor 40 %

Oi

I quantities:

Transmission

with

differential

Transmission oils

Transmission

number

-

Range

-

Model

year

1976

Sample serial No.

(7 digits)

Type

of

aggregate

Transmission

type

5

o

5 =

for

a 4 cyl .

motor

0=

5

gears

923

27

912

E

Single

dry

disk clutch

M

215

K Sph

4903

- 5492 (500 - 560)

215

Porsche - synchro-Iock transmission

923/02

11/35

i=3.1818

18/33

i = 1.8333

23/29

i = 1.2609

26/25

i = 0.

9615

29/21 i = 0.7241

12/21-20/38

i = 3.3250

Spiral conical

gear

Differential (Oerl ikon-gearing)

7/31 i = 4.4285

ZF

3.

0Itr

.

EP

oil,

Mil

2105 B standard, SAE

90

5 0 6 0001

Model year

Serial No.

6 0001

6 = 1976 0001

to

8000

SUSPENSION/BRAKES

The suspension

and

brake system in the

912

E

is

the

same

as

in the 911 models except

for

a

few

minor

details.

Front

axle independently suspended wheels on A-arms and struts, one torsion bar

for

each

wheel. Rack and pinion steering

with

safety column .

Safety steering wheel

with

padd :

ng,

stabilizer bar 16 mm dia.

Rear axle

independently suspended wheels on A-arms, torsion bar suspension

for

each

wheel .

WheelslTyres

Steel rims

5112

J x 15

fitted

with

165 HR 15 tyres.

Brakes

hydraulic, dual-circuit disk brakes,

with

solid disks.

28

40

FRONT

SUSPENSION

42

REAR

SUSPENSION

Vehicle alignment

specifications

The following specifications

are

valid

for

empty weight according

to

DIN 70020 (i.

e.

Vehicle including

full fuel tank,

spare

wheel

and

tool kit).

Front axle

Hight alignment :

Center

of

wheel

to

center line

of

torsion bar

99

mm

± 5

mm

3.90

in

Maximum difference from left

to

right

5mm

0.2 in

Total to-in

(pressed

15 kp)

Difference angle at a 20°

turning angle

0°

to

30'

Camber

(with

wheels straight

ahead)

0° 30' ± 10'

Maximum camber difference from left

to

right

10'

Caster

6° 5' ± 15'

Rear

axle

Hight

al

ignment :

From center

of

torsion bar

to

center

of

wheel

37 mm

± 5

mm/l.45

in

Maximum difference from left

to

right

8mm

To-in per wheel

20'

-

20'

Maximum difference from left

to

right

10'

Camber

0°

± 10'

Maximum difference from left

to

right

20'

29

40

FRONT

SUSPENSION

42

REAR

SUSPENSION

As previously mentioned, the

front

and rear suspension

is

identical

to

the Type 911 .

Shock

absorbers

-

rear

Either one

of

two

types

of

shock absorbers, 80ge

or

Woodhead ,

are

used

in production.

Shock absorber color code :

80ge black,

with

yellow

test band

Woodhead blue,

with

yellow

test band

Wheels

and

Tyres

Production

Wheel rims

front

and rear

5

1/2

J x 15 (steel)

Tyres

front

and rear

165

HR

15

Option

Wheel rims

front

and rear

5

1/2

J x 14

(LM

rims forged)

Tyres

front

and rear

185 HR 14

Spare wheel Inflatable

tyre

on a steel rim

5

1/2

J x 15,

with

a compressor or air tank

Winter

Tyres

Front

and rear

165

SR

15

MS

or

185170

SR

15

MS

on standard rims

5

1/2

J x 15

Note:

Wheel rims :

All

rims

have

a horn c

ontour

on the inner and outer side

(e.

g.

51/2J

x 15 H2)

Tyres:

All

tyres

are

tub

eless

Tyr

e pr

ess

ur

es

(cold) :

barometric pressure

(kp/cm

2

)

PSI

Front

2 bar

2

29

Also

for

wint

er tyres

Rear

2.35 bar

2.4

34

Reserve

(maximum)

2.0 bar 2.0 29

30

46

BRAKES

Hydraulic system/Brake failure warning device/

Hand brake warning light

As in the 911, the master brake cyl inder

is

fitted

with

a brake fai lure warn ing device . In the event

of

failure in one

of

the brake circuits a warning lamp

"BRAKE"

is

illuminated on the dash-board.

The

"BRAKE"

warning light also

serves

as

a hand brake warning light.

The hand brake warning lamp which

was

previously located in the combination instrument

is

no

longer

used.

31

46

BRAKES

Brake

disks

and

calipers

The

912

E

is

fitted

with

brake disks

without

ventilation on both

front

and rear axles.

(Refer

to

technical specifications

for

dimensions and

minimum

brake

pad

thicknesses).

Commencing

with

Mod. 76, a

type

brake caliper

is

installed on the

front

axle on all vehicles

including

911

's

o

Brake pads

Front

Rear

Jurid

231

GH

Textar TP

22

HH

Pad

thickness

10

mm

lOmm

32

TECHNICAL

SPECIFICATIONS

Front

suspension

-

steering

Wheel suspension

Torsion bar diameter

Stab

iIizer d

ia.

Shock absorber

Manufacturer

Steering

gear

Steering wheel dia.:

Standard

Optional

Steering ratio in the center (steering wheel

angle

to

wheel angle)

Turning circle dia.

Steering wheel turns

from

stop

to

stop

Steering

friction

(measured on steering flange

with

tie rods disconnected)

Rear

suspension

Wheel

suspension

Torsi

on

bar diameter

Stabi

Iizer

Shock absorbers

Manufacturer

Woodhead

Boge

Spring plate adjustment (inclination)

for

standard models

and

for

models

with

air conditioning

Independently suspended wheels on A-arms

and struts, one torsion bar

for

each

wheel .

18.8

mm/0.74

in.

16

mm/0

.

63

in.

Double acting hydraulic shock absorber

Boge/color coded : black

with

yellow

test band

ZF rack and pinion

400 mm115.75 in.

380

mm114.96 in .

17.78 : 1

10.9

mtr.l36

.76

ft.

3.1

0.8

to

1.4 Nm

(8

to

14 kpcm)

Independently suspended wheels on A-arms, one

torsion bar

for

each

wheel

23

mm/0

.9 in.

Double acting hydraulic shock absorbers

Either

Boge

or

Woodhead

Blue

with

yellow

test band

Black

with

yellow

test band

1°

spring plate inclination = approx. 8

to

9 mm (0.3

to

0.

35

in.) change in

hight

of

vehicle.

33

BRAKE

SYSTEM

TECHNICAL

SPECIFICATIONS

Foot brake

Tandem

master

cylinder

Bore diameter

Stroke

·Ratio at footbrake peddal

Free

travel : movement-rod/piston

Front

wheel

brakes

Brake disk O-dia.

Thickness

new

Minimum thickness after machini

ng

*)

Bra

ke

caliper piston d

ia.

Pad

thickness

Wear

limit

C

lea

rance

Pad

surface

area

for

each

wheel

Rear

wheel

brakes

Br

ake

disk O-dia.

Thickness new

Minimum thickness after

ma

chining

*)

We

ar

limit

Cleara

nce

Pad

su

rface

area

for

each

wheel

Hand

brake

Hand brake drum dia.

Wear

lim

it

dia.

Brake

shoe

width

Effective brake

area

per wheel

Wear

limit

for brake lining

Hydraulic, dual circuit disk brakes

with

brake

failure warn ing light

19

.05

mm/0

.75 in.

18113

mm/0

.

7110.51

in

.

5.4 : 1

1

mm/0

.39 in.

Solid disk - 282

mm111

.10 in.

12

.7 mm/0.5 in .

11

.5 mm/0.45 in.

48 mml1.89 in.

10

mm/0.39 in.

2.0 mm/0.079

in.

0.2 mm/0.0079 in.

76

cm

2

111

.78

sq

. in.

Solid disk - 290 mml11.4 in .

10.5 mm/0.41

in

.

9.5

mm/0

.374 in.

9.0

mm/0

.354

0.2 mm/0.0079

in.

52.5

cm

2

/8

.1375

Mechan i

cal

on both

rear

wheels

180

mml7

.086 in.

181

mml7

.126

in

.

25

mm/0

.98 in.

85cm

2

113.175sq. in.

2.0

mm/0

.079

in

.

*)

The brake disk must

be

symmetrically machined, the

same

amount on both

sides

of

the disk.

34

TECHNICAL

SPECIFICATIONS

Over-all dimensions

Length

mm/in.

4291/168.

94

Width

mm/in.

16101

63.39

Hight

mm/in.

13401

52 .76

Wheel

base

mm/in.

2271/ 89.41

Track

width

:

front

mm/in.

13601

53.54

Track

width

:

rear

mmlin.

13301 52.36

Road

clearance

mm/in.

1801

7.10

Weight

(DIN

70020)

kg

Ibs.

Empty

weight

1160

2258

Total weight

1400

3087

Axle

load

front

600

1323

rear

815

1797

Maximum load capacity

240

529

Maximum

roof

load

35

77

including

luggage

carrier

(Coupe only)

Fuel and Lubricants

Engine

The correct oil

level

Types

of

oil according

is

determined

by

the

to

A IP classification

dip-stick

as

described

in

SD

for

example:

the operating instructions

Summer SAE

30

Winter SAE 20

for

continuous temperatures

from - 15°C

to

O°C,

e.

g. 20 W 20. SAE 10 W

for

continuous temperatures

under

-15°C

.

Oil capacity

with

filter

change

3.5 Itr. approx.

Transmission incl. differential

3.0 Itr. transmission oil

according

to

MIL-L

2105

B,

SAE 90

35

TECHNICAL

SPECIFICATIONS

Fuel tank capacity

80 Itr. inc!. 8 Itr.

reserve

Brake fluid reservoir

0.2

Itr

. approx.

Windshield washer tank

8.0

Itr

. approx.

Performances

Top

speed

km/h

(mph)

178 (110.6)

Acceleration 0 - 100

km/h

s

13

.5

km

for

standing start

s

34.0 0 IN

empty

weight plus 1/2 load

Hill

climbing

ability

5

speed

transmission

1

st

gear

2nd

gear

3rd

gear

4th

gear

5th

gear

50%

27

%

17

%

11

%

7%

Chassis

number

range

Model

76

Sample serial number

(10digit)

912

Vehicle

type

6

Model year

6 = 1976

o

Motor

0=

912 E/2

Itr

.

o

Body

0=

0001

Serial No.

0001 - 9999

36

BODY/FITTINGS

The

body

on the

912

E

is

ide

nt

ica

l

to

that

of the 911 Model

s.

The

fol

lowi

ng

are

new on the 912 E

• Model

id

ent

ific

a

tio

n on r

ear

lid

• R

ear-

si

de

windows permanent installed

•

Ny

lon velour carpet

•

Seats

: Center

st

ripe in Scotch plaid, Tweed

or

braided material

37

BODY

/FITTINGS

The differentiating mark

is

the number identification

on

the rear lid .

The rear-side windows

are

permanently installed. The former

side

windows

are

available

as

an

option.

The single-stage heated rear-window

is

standardiequipment.

T

he

912 E interior upholstery consists

of

a nylon velour carpet, synthetic

seat

upholstery.

center stripe

of

Scotch plaid, Tweed or braided materials.

38

BODY/FITTINGS

As for the Type

911

Model 76, a radio

with

two

speakers, one in the right

and

one in the left door,

can

be

installed.

The speakerperforation on the

dash

board

was

removed.

Door locking push

button

The safety push

button

for

locking the

door

has

been

changed

from

8 mm

to

6.5 mm thickness.

This ensures

easier

opening

with

the key during variations in temperature.

39

BODY

/FITTINGS

Rear

cross-member

-

Engine

compartment

Various

fittings

and attachments are mounted on the rear cross-member :

for

air

filter

with

intake-air sensor

2

for

active carbon contai ner

3

for

the deceleration valve

4

for

the heating blower

motor

Motor

mountlR

ight-hand wheel well

The

motor

mount

-

left

and

right -

is

welded

to

the main

body

members (arrow)

Located in the right-hand wheel well

is

a compartment

for

the

AFC

control

unit

(5).

Also illustrated in the picture

is

one

of

the dampers

for

the safety bumpers

40

87

AIR

CONDITIONING

UNIT

Air conditioning unit

The air conditioning

unit

fitted

in the vehicle type

912

E

is

equipped

only

with

one condenser

which

is

secured to the engine lid.

Located on the receiver

dryer

is

a thermo switch (electrical switch) which disconnects the compressor

clutch

and

the air conditioning

unit

when the freon temperature

is

too

high.

When

the temperature

of

the freon drops the compressor clutch

and

the air conditioning

unit

are

turned on again.

41

~e

h

an

~e

gnit

i

on

-'-

p

_o

_in

_t_s

ired

I.

Required Maintenance for the Emissi

on

Control System 912 E

Required

Re

quired

Required

at 1,000 miles

every 5,000 miles

eve

ry

1

5,

000 miles

Change

Engine oil

Re

place

Engine oil filter

Replace

Valve clearance (at 5,000 miles, recommended for

Check

+ adjust

Check

+ adjust

maxi

mu

m e

ng

ine life, but not necessary to keep the

Check

+ adjust

(at 5,000 miles

on

ly)

Emission Con

tr

ol Warr

an

ty

in effect)

V-be

lt

s (including V-belt

for

air pump) check tension

Adjust

or

repla

ce

Adj

ust

and condition

if necessa

ry

Spark plugs Replace

Ignition distribut

or:

. _

Replace

Adjust

with electronic

dwell angle and timing

equipment

Check visually,

Ignition wiring,

distributor

cap and

rotor

replace

if

ne

cessary

Fuel filter Replace

EGR

syst

em

(reset

EGR

mileage counter) Check Visually *)

E

GR

system filter (reset

EGR

mileage counter)

Replace

*)

Evaporative control system (inc

l.

fuel cap, tank and

Check Visually

Check

Vi

su

ally

connections)

Crankcase ventilation hoses (control valv

e:

Check) Check visually

*)

Ex

haust s

yst

em Check for dam

ag

e

Check

+ adjust

Engine idle and exhaust emission (

CO)

Check

+ adjust

Air cleaner filter element (at least after

tw

o y

ea

rs)

Re

place

Air

pump, control valves, air injection hoses and

Check

connections

Filter element

for

ai

r pump Replace

Regular maintenance

of

the Emission Control System at 15,000 mile intervals is necessary to keep

yo

ur

Emission Control System War-

ranty valid.

*)

Additional service every

30,

000 miles.

II.

Ma

intenance and L

ub

rication Se

rv

ice

91

2 E

ReqUired at 1

,0

00 miles Req

Ui

re

d every 15,000 miles

Door

hinges

Lubricate

Door weatherstrips: Remove rubber residue from contacting areas

Maintain

and coat

with

talcum powder

or

other

su

itable rubber lubricant

Check and co

rr

ect

Change

Transmission oil

Change every 30,000 miles

Windshield washer, operation and fluid level

Check and corre

ct

Check

+ adj

ust

Front wheel bearing play

Front axle: Steering gear, tie-rod connections and rubber boots Check f

or

tightness

an

d leaks

Check

+ adju

st

Clutch pedal free play

Adjust

Br

ake system, all lines and hoses (incl. wear and leaks)

Check

Check Operation

of

lights, horn,

wip

ers and wash

er

Check

Headlight adjustment Check and

corr

ect

Ignition / s

teer

ing lock

an

d buzz

er

alarm Check

Sa

fety

belt warning light and buzzer alarm

Check

Batte

ry

elec

tro

lyte level

Check

+ corr

ect

pres

su

re

Tires

Check and

cor

rect pressure

During road

or

dynamometer test

Check Braking, clutch,

st

eering, heating, ventilation systems

Check

All

instruments, control and warning lights

Check

The recommended service intervals apply under normal driving conditions.

If

you drive mainly in

dusty

areas, check the air cleaner ele-

ment more often and replace

if

necessary. The condition

of

oil, and wear-and-tear items (such as tires, brakes, clutch lining) depend

greatly

on the amount

of

driving and on driving habits. Therefore, oil and wear-and-tear items should be checked more

fr

equently, and

if

necessa

ry

replaced

at

shorter intervals. Also, the battery electrolyte level should be checked more often. A complete

ma

intenance

and lubrication service should be performed at least once a year, preferably before the winter. The same applies

to

protective under-

coating

for

the vehicle.

42

Dr

. Ing. h. c.

F.

Porsche

Aktiengesellschaft

7000

Stuttgart

40

Postfach

400

640

Customer Service

Edited

by

Service School

Walter Muschweck

Werner Hahn

Hans Obinger

Dieter

Pr

inted

by

: Beck & Co.,

Stuttgart

40

Illustrations, descriptions and drawings are provided solely

to

clarify

the

text.

We

accept no responsibility

for

completeness

or

comformity

of

the

content

with

provisions valid

in

any

particular

case

. Subject

to

modification

without

notice.

1st

edition,

Sept.

1975

Porsche 912E 76 Service Information

Porsche 912E 76 Service Information

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