Fiat Project X1/9 User manual

The Complete Guideto Modification
for Competitionof the Fiat
X1/9
IMPORTANT NOTICE
Modifications of the type described
herein are not suitable for vehicles li-
censed for street use. They will also ren-
der the vehicle illegal for street use, as
Federal law restricts the removal or mod-
ification of any partof Federally required
emission control systems. Further, many
states have enacted lawswithvarious pen-
alties for tampering with, or otherwise
modifying, any requiredemission or noise
control system.
Though SCCA General Competition
Rules have been taken into account in
the preparation of these recommenda-
tions,
it is the responsibility of each indi-
vidual owner or driver to ensure that his
car conforms to the SCCA rules. Neither
Fiat Motors of North America nor its
dealers can be held responsible inconnec-
tion with any protestordisputes resulting
from illegal modification of parts.
Fiat vehicle and parts warranties are
voided if the vehicle or part is used for
competition or if they fail as a result of
modification. Competition parts or as-
semblies described herein as offered by
PBS Engineering or any other vendor are
sold "as is" without any warranty what-
soever. The entire risk as to quality and
performance of such parts is with the
buyer.
INTRODUCTION
The informationcontained inthis vol-
ume has been prepared by PBS Engineer-
ingof Garden Grove, California at the re-
quest of Fiat Motors. In
it, PBS makes
available tothe SCCA competitor thesum
total of many years of experience inthe
preparation for racing of Fiat cars. It is
our hope that this information will be of
value to those who compete with Fiat
XI19 automobiles. Clarification on the
methods described, if needed, should be
obtained directly from PBS Engineering.
This book is not intended as a sub-
stitute for the shop manuals and guides
that Fiat Motors makes available for the
servicing of its products. It is written to
be used inconjunctionwithsuch manuals
and guides.
Fiat Motors wishes you the best for
success in your competitive efforts with
the
XI 19.
Fiat Motors of North America, lnc.

CHASSISlBODY 3
REAR SUSPENSION 3
Rear Suspension BodyIFrame Modifications 3
Rear Strut Modifications 5
Rear Adjustable Camber Plates 6
Rear Anti-Roll Bar
8
Rear Suspension Bushings 8
Left Rear Control Arm Modification 9
FRONT SUSPENSION
AND STEERING
9
FrontSuspension BodyIFrame Modifications 9
Modifications to the FrontStruts 11
FrontAdjustable Camber Plates 11
Steering Rack and Mounting Modifications 13
FrontAnti-Roll Bar 13
FrontSuspension Bushings 14
BRAKES 14
Front Brakes (F-Production 1500XI191 15
Front Brakes (G-Production 1300 XI19 15
Rear Brakes (G-and F-Production) 15
Brake Master Cylinders 16
ROLL CAGE 16
WHEELS, TIRES AND
WHEEL ALIGNMENT
Wheels
Tires
Wheel Alignment
Dry Sump Oil System
Cylinder Bores
Crankshaft
Pistons
Connecting Rods
Bearings
ENGINE ASSEMBLY 29
Checking Piston, Head and Valve Clearance 29
Checking Cam Timing 29
Head Bolts 31
Pan Baffle 31
CARBURETOR AND INTAKE
MANIFOLD MODIFICATIONS
31
Carburetor 31
Intake Manifold 32
IGNITION SYSTEM 3 2
1300 IgnitionSystem 32
1500 Ignition System 32
EXHAUST SYSTEM 32
TRANSMISSION, FINAL DRIVE,
CLUTCH AND FLYWHEEL
33
Changes Associated With 5-Speed Gearbox 33
Close Ratio Gears 33
Bearing Sleeves 33
Differential 33
Flywheel and Clutch 33
1500 C-V Joints 34
BODY MODIFICATIONS
Seat
Fender Flares
Windshield
Grill
Air Dam
PLUMBING, ELECTRICAL
AND INSTRUMENTATION
Oil System
Fuel System
Brake Plumbing
Clutch Plumbing
Cooling System
Fire SuppressionSystem
Wiring
Instrumentation and Switches
ENGINE
CYLINDER HEAD
AND VALVE GEAR
Ports
Combustion Chamber
Valves
Valve Springs
Cam and Cam Timing
Tappets
Valve Guides
Head Gasket
ENGINE SHORT BLOCK
@copyright~iatMotors of North America, Inc.
First Edition-1979
All rights reserved. Neither this book nor any part thereof may be reproduced in
any form without express written permission from Fiat Motors.

CHASSISlBODY 3
REAR SUSPENSION 3
Rear Suspension BodyIFrame Modifications 3
Rear Strut Modifications 5
Rear Adjustable Camber Plates 6
Rear Anti-Roll Bar
8
Rear Suspension Bushings 8
Left Rear Control Arm Modification 9
FRONT SUSPENSION
AND STEERING
9
FrontSuspension BodyIFrame Modifications 9
Modifications to the FrontStruts 11
FrontAdjustable Camber Plates 11
Steering Rack and Mounting Modifications 13
FrontAnti-Roll Bar 13
FrontSuspension Bushings 14
BRAKES 14
Front Brakes (F-Production 1500XI191 15
Front Brakes (G-Production 1300 XI19 15
Rear Brakes (G-and F-Production) 15
Brake Master Cylinders 16
ROLL CAGE 16
WHEELS, TIRES AND
WHEEL ALIGNMENT
Wheels
Tires
Wheel Alignment
Dry Sump Oil System
Cylinder Bores
Crankshaft
Pistons
Connecting Rods
Bearings
ENGINE ASSEMBLY 29
Checking Piston, Head and Valve Clearance 29
Checking Cam Timing 29
Head Bolts 31
Pan Baffle 31
CARBURETOR AND INTAKE
MANIFOLD MODIFICATIONS
31
Carburetor 31
Intake Manifold 32
IGNITION SYSTEM 3 2
1300 IgnitionSystem 32
1500 Ignition System 32
EXHAUST SYSTEM 32
TRANSMISSION, FINAL DRIVE,
CLUTCH AND FLYWHEEL
33
Changes Associated With 5-Speed Gearbox 33
Close Ratio Gears 33
Bearing Sleeves 33
Differential 33
Flywheel and Clutch 33
1500 C-V Joints 34
BODY MODIFICATIONS
Seat
Fender Flares
Windshield
Grill
Air Dam
PLUMBING, ELECTRICAL
AND INSTRUMENTATION
Oil System
Fuel System
Brake Plumbing
Clutch Plumbing
Cooling System
Fire SuppressionSystem
Wiring
Instrumentation and Switches
ENGINE
CYLINDER HEAD
AND VALVE GEAR
Ports
Combustion Chamber
Valves
Valve Springs
Cam and Cam Timing
Tappets
Valve Guides
Head Gasket
ENGINE SHORT BLOCK

To prepare the XI 19 for SCCA production racing, the car
must first be stripped down completely to the bare body
structure. Then it can be modified and re-assembled. All
non-essential parts are left out in order to reduce weight,
unless required by SCCArules. The suspension ismodified
to lower the car and optimizesuspension geometry within
rules constraints. The brakes are modified to improve ef-
ficiency and heat rejection, and to allow front to rear
brake bias adjustment.
A complete roll cage is incorpora-
ted into the body structure to comply with SCCA safety
rules and to stiffen the body structure. Fiberglass fender
flares are added to cover the wider racing wheels and tires
and to comply with SCCA rules.
REAR SUSPENSION
The SCCAproduction rules allow anumber of suspension
changes including relocating the position of the inboard
suspension pick-ups, substituting snock absorbers and
springs, eliminating the rubber in suspension bushings
and the addition or modification of anti-roll bars. Work-
ing within these rules, the car should be lowered as much
as practical and suspension pick-ups modified to regain
acceptable suspension geometry control in the lowered
condition.
Rear SuspensionBodylFrameModifications
After stripping the car downtothe bare bodylframe struc-
ture and setting it on stands, the rear suspension modifi-
cations can be started. The object of this modification is
to lower the rear of the car
1-112 inches, in addition to
the dropinheight achieved by using smaller diametertires,
and to end up with approximately stock camber change
as a function of wheel deflection,
A simplified discussion of strut suspension geometry
will explain the need for relocating theinboard suspension
points to maintain good geometry control with alowered
car. First it is necessary to remember that, neglecting the
effectsof camberchange as afunction of wheel deflection,
when the car leans to the outside in a corner, the wheels
will lean with it and the outside wheels will go topositive
camber. This reduces the effective tire contact patch and
loses lateral adhesion. Thus, it is desirable to have the
camber change in a negative sense, when the wheel is de-
flected upward from its normal static position. This ef-
fect plus the initial negative camber adjusted into the
suspension will help to compensate for the positive cam-
ber introduced by chassis lean in cornering.
With the strut type suspension, negative camber is in-
duced by moving the bottom of the strut outward as the
wheel is deflected upward. This can be accomplished by
having the outer attach point, of the lateral control arm,
lower than the inner attach point, at the chassis. Then,
when the wheel moves upward, the outer end of the con-
trol arm will move outboard, in an arc about the inner
attach point.
The effective kingpin inclination, towards the inside
at the top, also helps induce negative camber as the strut
gets shorter. Lowering the car to achieve a lower center
of gravity by using shorter springs increases the effective
kingpin inclination, which is desirable; however, it also
lowers the inboard pick-ups of the lateral controlarm rel-
ative to the outboard pick-up at the strut. Thisis undesir-
able because it reduces the gain in negative camber as
the wheel deflects upward. However, by relocating the
inboard transverse pick-up point at the chassis, this un-
desirable effect can be alleviated. The inboard pick-up
should be raised the same amount as the car was lowered
by shortening the nominal working length of the struts.
The rear transverse control arm has twoinboard pick-

Cutting OutRear Crossmember
Removing Complete Rear Crossmember

up points. Lateral position is primarily controlled by the
rear inboard pick-up point while the foward pick-up pri-
marily controls fore and aft location. For this reason,pri-
mary effort should be directed toward raising the rear
inboard pick-up.
The first step in modifying the rear suspension is to
scribe a line on the rear engine bay panel above the rear
crossmember and parallel to a line through the rear in-
board suspension pick-ups. Measure the vertical distance
between the line and the rear suspension pick-ups and re-
cord it forreference in relocatingthese suspension points.
Cut the rear crossmember out of the car as aunitwith
the rear inboard suspension pick-ups intact. This can be
accomplished by drilling out the spot welds on either end
from inside the fender wells and cutting as shown with
an air chisel. This operation should be done carefully so
damage to this unit is not sustained while removing it.
While
the rear crossmember unit is removed from the
Pilot Holes Drilled In Forward Rear Suspension Brackets
car additional T.I.G. welding on the suspension brackets
and associated panels is recommended to supplement the
existing spot welds. Also, 112 inch washers should be
welded on the suspension tabs.
Cut the rear crossmember as required to allow it to
be raised vertically in the car by 1-112 inches. Use the
scribe marks made previously.
The forward inboard pick-ups of the rear suspension
are less critical, but they should be raised also as much as
practical. These pick-up points are drilled after the body
is assembled at Bertone, so there will be some variation
from side to side in the amount of clearance above the
existing hole. Typically, these holes can be raised about
9/16 inch andjust redrilled in the existingbracket. Check
your car on
both sides to be sure how much you can
raise the holes and still clear the suspension arm.
Centerpunch the foward brackets 9/16 inch above
the existing hole, or other dimension (as determined
above).
rill a small pilot hole through both sides of
Modified Rear Crossmember Clamped In Place For Welding
both brackets.
Weld the original holes shut in the forward brackets
-
and grind them flush.
Drill the new holes to size.
In order to change the
inboard rear suspension bushings to 112 inch spherical
joints, these holes should be drilled to 112 inch.
Clamp the modified rear crossmember in itsnew po-
sition and install the two transverse rear control arms in
place with bolts through all
4 inner pick-up brackets to
insure proper relative alignment.
T.I.G. weld the rear crossmember in place.
Rear Strut Modificatibns
The function of the rear struts includesprovision of asuit-
able spring and damping unit as well as part of the sus-
pension geometry control as discussed earlier. The spring
and damping function is a compromise, which must be
stiff enough to limit deflections and resultant geometry
changes and to prevent suspension bottoming under nor-
mal racing conditions, andyet be soft enough tominimize
Modified Rear Crossmember Welded In Place

Modified Front and Rear Strut Housings and Carrera Insert
wheel loading changes which can cause loss of adhesion
in the presence of bumps during cornering. The optimum
compromise will be somewhat stiffer for a smooth track
than for a rough track, in general. However, making
changes in spring rates gets rather complex forthetypical
SCCA racer and should not be necessary in most cases.
Adjustable shocks sound like a relatively good idea, but
in practice they are not practical, particularly with a
strut type suspension. Shocks which must be collapsed
in order to adjust them require removal of the spring in
order to collapse them. Also, most adjustable shocks are
only adjustable for rebound damping. This works fine
for ride control, but for racing they should be relatively
loose on rebound in order to let the spring push the tire
back down onto the ground. In racing the compression
stroke on the shocks becomes more important, in order
to keep the tire from leaving the ground on the upward
stroke. Thus, a shockabsorber which works well forstreet
use will not necessarily make a good racing shock, and
vice versa. Also, it must be remembered that the primary
suspension element is the spring and radically alteringthe
damping will not compensate for the wrong selection of
spring rates. Thus, for SCCA production racing a good
quality, non-adjustable racing shock, which is calibrated
for the approximate load and spring rate of the
X1/9,
should be adequate for most racing conditions. The
springs should be changed to a higher rate spring, with
an adjustable lower spring perch, to allow ride height ad-
justment and balancing of suspension loads from corner
to corner. The following paragraphs will describe rear
strut modifications required to use Carrera
1974F coil-
over shock conversion kits and Carrera
3263.5-F strut
inserts. The modified parts are included in PBS Kit
Number
2.
Completely disassemble the rear strut assemblies.The
only part which will be used is the outer strut housing.
Cut thestock spring perch off from the struthousing.
The heavy walled threaded tube supplied in the Car-
rera coil-over conversion is longer and hence heavier than
front and Rear Anti-RollBars
necessary. Thistube can be cuttoalength of 2-718 inches.
Mount the threaded tube
3 inches above the suspen-
sion bracket on the strut housing.
If Carrera
3263.5-F strut inserts are used, it is recom-
mended that an indexingwasher be welded on the bottom
of the insert per Drawing
1. This indexes positively inside
the bottom of the strut housing in the same fashion as
the stock insert andprecludes any possibility of undesired
motion at this point.
Rear Adjustable Camber Plates
Adjustable camber plate assemblies are recommended for
the
X1/9 for racing because they allow relatively simple
camber adjustment which will be useful in chassistuning.
Also, the camber plate is thinner than the stock attach-
ment and allows the car to be lowered farther without
limiting travel. The following paragraphs describe the in-
stallation of a Carrera
1875HF camber plate assembly.
These are included in PBS Kit Number
2.
Referring to the pictures, cut and fit doublers from
1-112 inches wide by 118 inch steel, on top of the strut
CompleteStrutAssemblies WithCarrera Coilsand CamberPlates

Camber Plate Installation
Doublers Welded In Place For Camber Plate

towers. Note that the two studs adjacent to the slot in
the lower stud plate fit in the center of the existing hole
in the strut tower. Drill a hole for the third stud.
Weld the doublers to the top of the strut tower with
the stud plate in place to assure proper alignment. Note
that the stud plate assembles from underneath the strut
tower.
Install the moveable camber plate per Carrera in-
structions.
RearAnti-RollBar
The XI19 doesn't come with anti-roll bars on either front
or rear. In order to minimize chassis roll in cornering,
which couples into a reduction in negative camber, it is
desireable to increase suspension roll stiffness substan-
tially from stock. Thic is partially accomplished by using
stiffer suspension coil springs. Anti-roll bars are recom-
Camber Plate Installation Inside Strut Tower. Front Is Shown,
mended on both ends to increase roll stiffness further.
Rear Is Similar
Altering the anti-roll bars tovary the respective roll stiff-
ness, between the front and rear of the car,is also a val-
Rear Anti-Roll Bar Installation
Rear Anti-Roll Bar Installation
uable tool in chassis tuning for controlling the degree of
under or oversteer.
Drawings2,3,4and
5 showthe suggested rear anti-roll
bar configuration. The size can be alteredtosuit the driver
and individual car. Increasing the diameter of the rear
anti-roll bar will increase the oversteer. A 518 inch diam-
eter rear bar works well with the other modifications
described here.
Fabricate the rear anti-roll bar mounting brackets per
Drawing 3 and weld them to the chassis as shown in the
pictures.
Fabricate the threaded blocks and weld them to the
rear control arms as shown in Drawing
5. The rear anti-
roll bar can be purchased as PBS Kit Number 6.
Rear SuspensionBushings
Alinabal CBC-8-B2,or equivalent, 112inch spherical bear-
ings can be adapted to replace the rubber bushings in the
rear suspension arms. PBS Kit Number 11 contains the
required parts for this conversion.
Remove the stock rubber bushings and their steel
jackets by pressing them out of the inboard ends of the
two rear suspension arms.
Since 14mm spherical bearings are not readily avail-
able, the 112 inch Alinabal CBC-8-B2 units are recom-
mended. These have an outside diameter of
1.3 12 inches.
This diameter must be ground to 1.260 inches so they
can be pressed into the suspension arms.
Press the spherical bearings into the center of the
openings in the suspension arms. Fabricate locating
spacers from 1-114inches
O.D. 16 ga. mild steel tubing.
These are inserted on either side of the spherical bearing
to retain it centered in the arm. Weld the locating spacers
to the outer edge of the arm, being careful to seat them
squarely on the outer race of the spherical bearing.
Fabricate spacers for the 112 inch bolts from 314 inch
O.D.
x .I20 wall mild steel tubing. These are used to

make up the distance between the suspension mounting
brackets and the spherical bearing ball.
Weld heavy steel 112 inch washers onto the rear sus-
pension brackets concentric with the stock 14mm holes.
This can be done while the rear suspension crossmember
is removed from the car (see page 5). The forward brack-
ets should be drilled to 112 inch when they are relocated
in position.
Assemble the arms to the chassis and fit-checkall of
the spacers. Use high strength 1/2-20bolts, 3-112inches
long, and self-locking nuts. Be certain that the bolts
clamp the spacers and spherical balls securely between
the mounting bracket ears so that the bolts will not work
loose and wear the mounting holes.
Left Rear ControlArm Modification
The left rear suspension arm must be modified for clear-
ance if the 5-speed transmission is used.
Cut the arm for clearance as shown and box it in lo-
cally with 16 ga. mild steel T.I.G. welded in place. This
operation is best performed with the engine and gearbox
installed and the suspension, less the coil spring, in place
so that proper clearance can be ascertained by moving the
suspension throughout its travel range.
FRONT SUSPENSION AND STEERING
Modifications to the front suspension parallel those to
the rear suspensionin general, but the detailsare different.
Left Rear Control Arm
Also, the steering function requires additional modifica-
tion in the front. The stock X1/9 actually is higher in
front than in the rear. In order to improve aerodynamic
penetration and stability the front should be lowered
more than the rear of the car. Dropping the front about
2-112 inches in addition to the change in tire diameter
works well with respect to the 1-112 inch lowering of
the rear.
Front SuspensionBodylFrame Modifications
In order tolower the front 2-112 inches, it is desirable to
raise the inboard transverse suspension pick-up at the
Front Inboard Suspension Brackets

Cut-OutFor Front Suspension Brackets Front Suspension Bracket Welded In Place
Completed Front Suspension Bracket
Box In Suspension Bracket (Note Trailing Arm Clearance Notch)

chassis 2-112 inches so that the transverse control arm
will maintain approximately stock geometry. The ra-
tionale for this follows that given on page
4 regarding
the rear suspension. This requires extensive cutting and
fabrication of new inboard suspension brackets.
First fabricate the new front inboard suspension
brackets per Drawing 6. These are included in PBS Kit
Number
9.
The bodylframe must be cut out above the stock in-
board suspension pick-up toaccommodatethenew brack-
ets. Refer to the pictures for guidance. Leave the rear
stock mounting ear intact for a location reference for
the new bracket. An air chisel and asmall abrasivecut-off
disk, in an air-driven die grinder, will be useful tools for
cutting and fitting the new bracket.
When the new bracket has been fitted so that the sus-
pension pick-upis moved directly upward by 2-112inches,
the bracket can be T.I.G. welded in place.
Fabricateand fit theadditionaldoublers and stiffeners
as shown in the pictures and weld them in place.
Fabricate new front trailing arm attachment brackets
asshown in Drawing
7. PBSKit Number 7 hasthese parts.
Modify the trailing arm and the front transverse con-
trol arm per page
14 and temporarily install them.
Cut the bodylframe locally to clear the trailing arm
in its maximum upward travel. Weld up thenotched area,
piecing in the hole as required.
Modifications to theFront Struts
The front struts are basically the same as the rear struts
and are modified in similar fashion. Since the front will
be lowered more than the back, it is necessary to move
the suspension bracket up on the strut housing in order
to retain adequate deflection capability. The following
instructions assume that Carrera coil-over shock conver-
sion kits will be used. PBS Kit Number
2 contains the
modified parts.
Disassemble the stock front strut assemblies. Only
the stock housing will be used.
Cut off the stock front lower spring perch.
Using a lathe, cut the weld off of the bottom of the
suspension bracket so the bracket can be moved up on
the strut housing. Raise the bracket 15/16 of an inch
and re-weld it to the housing.
Install the threaded collar for the coil-over kit down
against the suspension bracket.
Front Adjustable CamberPlates
The front camber plates are identical to the rear ones
and are installed in the same manner. See photo below.
CamberPlate Installation and Brake Master CylinderInstallation

Cut-OutsFor Steering Rack Clearance and Access
Steering Shaft Location and Brake Master Cylinder Push Rod

Steering Rack and Mounting Modifications
The design of the suspension and steering is such that it
is impossible to eliminate bump steering completely on
the X1/9. However, raising the steering rack by the same
amount as the inboard suspension pick-ups will keep
bump steer from becoming a serious problem with the
lowered car. The required parts are part of PBS Kit
Number 9.
Remove the plastic bushing inside the right-hand end
of the steering rack and fabricate a new one from alu-
minum bar. Reassemble the steering rack. Be sure to
constrain the bushing from falling out by swaging over
the end of the rack tube or welding a retaining washer
on the end of the rack.
Fabricate the two new steering rack mounting brack-
Steering Rack Brackets and Mounting Modification
ets per Drawings 8 and 9.These are used tomove thesteer-
ing rack up
2-112 inches and to provide a solid mounting
for the rack, rather than the stock rubber cushioned
mounting.
Cut a flat on the left hand steering rack mounting
boss tomatch the flat area on the left bracket.
The inner front trunk skin must be cut in several
places, to provide access to the new rackmountingbrack-
ets, to allow vertical motion of the connecting links be-
tween the rack and the steering arms, and to allow access
for adjusting the front toe. See the pictures for guidance.
Don't cut the battery box back more than necessary as
the floor must be left wide enough to support the air-
craft battery. All holes cut must be covered to comply
with the
G.C.R.
Install the steering rack after cutting a new hole for
the steering splined shaft to feed through into the driver
compartment. Cover the original hole.
Front Anti-Roll Bar
The rationale for a front anti-roll bar parallels that given
for the rear bar. The front bar in general should contrib-
ute more roll stiffness than the rear bar, particularly
with a mid-engined car, in order to preclude excessive
oversteering. The car is low enough thatit is very difficult
to find adequate room for a bar and mounting brackets
under the front of thc car. Thcrcfore, it is recommended
that the front anti-roll bar pass through the front trunk
compartment even though this creates a few problems.
The front bar is essentially the same as the rear one ex-
cept for diameter.
A 13/16 inch diameter front bar is
recommended if the suspension is modified as described
in this manual. PBS Kit Number
5 includes this bar.
Front Anti-Roll Bar Mounting Bracket

Front Anti-RollBar Pickup Brackets and Front Arms and Trailing Links
Fabricate the front anti-roll bar per Figures 2,4, 10
and 11. Only weld the arm on one end of the bar as the
bar must be inserted through the body before the op-
posite end is welded in place.
Fabricate the front anti-roll bar mounting brackets
(Drawing 10) and bearing blocks (Drawing
4) and install
them in the front trunk.
Fabricate the anti-roll bar pick-up brackets, which
mount on the transverse suspension control arms, per
Drawing 11.
Install the anti-roll bar and weld the arm on the bar
in the car. Align the two arms so they lie in the same lat-
eral plane before welding.
Front SuspensionBushings
It is recommended that the rubber bushings at the in-
board end of the front transverse control arms and the
front end of the front trailing linksbe replaced by spher-
ical joints and rod ends respectively. Note that since a
line extending the axis of the bolt through the inner
transverse pick-up doesn't intersect the pivot point of
the trailing link, a straight bushing cannot be used with-
out causing binding. Therefore, any non-flexible suspen-
sion bushing must have freedom in two axes. Eliminating
the rubber joints and replacing them with sphericaljoints
greatly improves steering accuracy under racing corner-
ing loads.
Bore the inner ends of the transverse control arms to
accept 7/16 inch sphericaljoints. Alinabal PIN CBC-7-B2
joints or equivalent are recommended. Bore in,leaving a
shoulder to seat the ball joint against, such that it will be
centered in the arm. A piece of thin-wall tubing can be
pushed in after the ball joint and tack welded in place to
retain the ball joint. PBS Kit Number
8 has these parts.
Cut and thread the ends of the trailing links as shown
inDrawing 12toaccept
518 inch female rod ends. Alinabal
PF-10-G rod ends or equivalent are recommended. Also
fabricate spacers per Drawing 13. This modification is
included
~;PBS Kit Number 7.
BRAKES
The X1/9 has four-wheel disc brakes
well in stock form. However, there which work quite
are a number of
changes which can be made toimprove their performance
under racing conditions. The 1500 F-production car is
allowed to use Lancia 10inch disc brakes as an alternate.
These are recommendedfor the front. FrontX1/9 calipers
can be used on the rear of both
G and F cars toeliminate
the hand brake mechanism. Some method of adjusting
the relative brake pressure between the front andthe rear

systems is essential for proper brake balance. Probably
the best way to achieve this is to use two separate master
cylinders with an adjustable linkage betweenthem. These
can be mounted in the front trunk compartment to sim-
plify maintenance.
Front Brakes (F-production1.500 X1/9)
Several modifications are required in order to use the al-
ternate Lancia 10inch discs on the front of the Xl/9.
Use the rear discs from a Lancia Beta,PIN 82346816.
Machine the inside of the discs to fit over the X1/9 front
axle flange.
Modify X1/9 stock 3116-inch-thick wheel spacers so
one can be used between each disc and the X1/9 axle
flange. The spacer
O.D. should be cut to 4.380 inches
and the I.D. must be relieved to clear the radius on the
axle so it will seat properly.
Carefully deburr the spacer and disc and assemble
them on the axle. Check disc lateral runout with a dial
indicator. This shouldn't exceed about .005 inch T.I.R.
If it does, correct the problem to avoid having the disc
runout push the pads back in operation.
The aluminum front calipers from the 1500 X1/9
will work well with the Lancia 10inch discs, but modi-
fied Lancia Beta front caliper mounting brackets and
brake pads must be used. The Lancia caliper bracket is
casting number 1419979. The caliper retaining blocks
and clips and the pad retaining clips from the Lancia
should also be used. The Lancia caliper itself could bc
modified and used, but it is a doublepiston unit with two
separate hydraulic systems for redundancy and is large
enough to cause space problems in the X1/9 front end.
Thus, the use of the X1/9 caliper with the Lancia caliper
bracket and brake pads makes a better installation.
Modify the Lancia caliper brackets as shown in
Drawing 14.
Fabricate the caliper mount adaptors per Drawing 15
and weld them to the modified Lancia brackets.
Assemblethecaliper assembliesusing Lancia hardware
except for the X1/9 aluminum caliper itself. Use the Lan-
cia brake pads, PIN 82315602.
Assemble and plumb the brakes on the car. Note that
the steering arm may have to be ground down slightly to
clear the Lancia disc. Check forclearance between the cal-
iper and the wheels and correct any problem areas. Leave
the front dust shield off to allow more air circulation.
The Lancia brakes are available as PBS Kit Number 1.
Front Brakes (G-production 1300X1/9)
Alternate brakes are not allowed on the G-production
car. Remove the dust shields and use a good grade of
competition brake pads.
Rear Brakes (G- and F-production)
Although Lancia brakes could be used on the rear of the
F-production X1/9, this isn't necessary. It is recommen-
AoA
hnrrm~mr thqt ~tnrk frnnt XI /Q ralinpre h~ IIFP~ nn
Front Brake Assembly (F-Production) Using Lancia Discs
Lancia Disc, Modified Spacer, Modified Lancia Caliper Bracket
Mndified Lancia Calioer Brackets

the rear since this eliminates the hand brake mechanism
and allows the use of the thicker front brake pads. Leave
the dust shields off.
BrakeMaster Cylinders
The stock tandem dual master cylinder in the X1/9 is a
good unit, but there is no provision for adjusting balance
between the front and rear brakes. Also, thestockmaster
cylinder is located in a very inaccessible location which
complicates any maintenance on the master cylinder. It
is possible to use the stock master cylinder for racing if
you add a manually adjustable pressure limiting valve in
the line to the rear brakes. The valve used on the
128
sedans can be used for this function if you add a screw
adjusting feature to it. The preferred set-up for racing,
however, is to incorporate two master cylinders with an
Brake Master Cylinders
adjustable balance bar between them. Refer to the pic-
tures on this installation.
Use two
314 inch Girling master cylinders. Fabri-
cate the master cylinder mounting bracket and linkage
per Drawing
16.
The brake pedal has an existing hole, below the piv-
ot, which can be used for the new linkage to drive the
master cylinders. Cut a hole into the front trunk com-
partment to allow the brake pushrod to pass through.
Assemble the mastcr cylinder bracket,rocker arm and
pushrod, and locate the assembly on the rear wall of the
front trunk as shown in the pictures. Weld the bracket to
the car.
After painting the installed master cylindermounting
bracket, the cylinders and linkage can be assembled. Set
up the brake balance so the rocker arm pivot is slightly
closer to the front master cylinder for initial testing. Ad-
just this balance as required to obtain optimum front to
rear brake balance under racing conditions. PBS Kit
Number
12 covers the dual master cylinder parts.
Steering Shaft Location and Brake Master Cylinder Push Rod
ROLL CAGE
All SCCA production race cars built in 1979 andlaterare
required to have a complete roll cage as defined in the
current SCCA G.C.R. Since it is required, it is desirable
to integrate the cage carefully into the basic car structure
to enhance the stiffness of the chassis as well as to pro-
tect the driver. In addition, the cage should be designed
in such a way as to minimize its aerodynamic drag. The
roll cage described in subsequent paragraphs complies
with SCCA safety criteria and the above objectives as
well asbeing integrated intothebasic stylingof the X1/9.
Fabricate the main hoop and the front hoop from
1-112 inch O.D., .I20 inch wall, mild steel tubing per
Drawings
17 and 18. The bottom ends of the two hoops
Front Camber Plate Installation and Brake Master
CylinderInstallation
will need to be trimmed to fit the installation.
Fabricate four base mounting pads from angle iron
or by bending steel plate and weld them onto the outer