Advanced
HOT TECH-TIPS for X19 petrol heads
Simple
performance modifications on the Fiat1300cc, 4speed roadster to make it
drive better.
These modifications should give better feel and driveability
to any X19 with minor cost.
This car should look, feel, drives equal to a standard 1500
or 2000 with all the benifits of the 1300.
Most of these modifications have been tested by myself
or are used by other owners of X19s. This car is the fore runner to my
V6 project. Fiat 4 cylinder motors are almost bullet proof, this include
the 1300, 1500 SOHC and 2000 DOHC which is essentially the counterpart
to the famous Ferrari 500 two litre that won more races than any other
Ferrari and made Ferrari famous.
Most enthusiast forget that Ferrari believed in small
capacity over square, high reving, high performance engines in the 1500
to 2500cc bracket. Many were 4, 6, 8 and 12 cyl.
This article will introduce the new comer to a "budget
rebuild" project which should give a engine lifespan of 50,000 kms.
Here are some
specs.
ENGINE
The motor had about 250,000 km, it was stripped and cleaned
to observe wear.
The main objective is better air flow and balancing. All reused parts
should have a smooth unscored finnish, if ok use 1200 grade wet /dry in
turpintine to linish the surface.
Head
The head was sent out for welding around the water holes which had
corroded so bad that the head gasket blew. After welding the inlet and
exhaust ports were reamed out to 28mm approx by using a wooden dowel with
various grade of emery paper on a hand drill, starting with 80 grit and
finishing off with 240 grade, forget polishing since there is no real gains.
Grind out the inlet and exhaust guide bump
with a steel burr in a drill. Forget about bigger valves its not needed,
reuse the old ones (if good) by dressing the valve head on a emery disk (150 grade)on
a bench grinder, carefully make sure the valve edge is rounded to a bull
nose, only a few thou is needed.
Next insert new guides and grind off the guides so they are flush with
the ports, I didn't leave any guide protruding, send head out for surface
grinding and recut the valves and seats, then lap them in. Set lash gap
on the tappets at 0.015" for inlet and exhaust, I always felt the standard
gap was to much and noisy, besides less gap gives a slightly better cam tuning
on duration.
The end result should be a better breathing head.
Block Honing
With the block I didn't rebored it since I reused the standard pistons
which someone had put in probally about 50-70,000 kms before, the pistons
were ok with only a very minor scuff on the skirt. Hence I honed the bore about
0.002" which made the bores round again with only a minor half thou lip on the bore
from the top ring which was hand dressed with 240 wet/dry on a half round
wooden block. The bore to piston clearance is about 0.006" which is twice
the stock, this is not a problem since the engine runs on 50/70 SAE.
Deck was surfaced ground less than a 0.001" for true level surface.
Crank shaft looked good so it was hand linished with 1200 paper in turps,
then all the parts from front pulley to flywheel and clutch plate with
pistons and rods were balanced to zero or 1 gram tolerance.
Balancing
Fly wheel was surfaced and lightened by trimming outer edge to presure
plate edge and leveled on the back, then 13mm holes spaced 6mm apart between
the presure plate flange were drilled through. The fly wheel and plate
weigh in at about 7.25 kg which is fine, remember its not the total lightness
you want to achieve but circumferential mass of the outer part, so theres
no need to machine the middle only from the ring gear to the presure plate
and on the back.
What you should end up with is a fully balanced free spinning motor
with loose pistons and a free flowing head.
Pistons
New piston rings were fitted, however the top moly ring was bevelled
by about 5-10 thou so it would clear the any bore lip (just in case when
the motor is reved to the max and all the parts extend to their minimum
clearance). If you want a little more hp then go for 11:1 pistons, but I
stuck with the stock 9:1 ratio.
New bearings, thrust washers were fitted, all gasket surfaces were sanded
flat with a block and aviation gasket non hardening cement used.
Shim the the valves springs by inserting an extra stock washer under
the springs so there are two, this should give better tension, check that
there is no spring crushing, there normally isn't.
Reuse the stock cam shaft, but I set the cam timming 1 tooth extra before TDC
which advances the inlet opening valve to about 20 degrees on a stock cam
(12-52/52-12)in theory this should help top end cylinder charging.
Manifolds
Next find an X19 1500 exhaust manifold and run a 28 or 30 mm high speed
steel ball bur (or make one) on a flexible drill extention through the exhaust tube and
clean up the flanges so they are slightly larger than the exhaust port,
, this manifold is excellent and as good as extractors. Next make up a 2 into 1
manifold pipe of 35 or 38mm (1.5") collector into a 50 or 63mm (2.5") bent to
the muffler of your choice.
Inlet manifold is stock which is treated the same as the exhaust, ensure the inlet port
is slightly larger than the inlet manifold flange for good transition.
Check all gaskets port openings clear the port holes.
These manifolds do every thing most guys want up to 7-7500 rpm, they are good
reasonably breathers.
Carburetor
A weber 34/34 prinary and secondary Lancia 2000 single carb rejeted
by your carby shop should give you good results without all the hassels
of twin carbs and the problem of being RPM sensitive. However a twin
barrel 32/36 carb is probally better will give good low end velocitities
when ticking around town or cruising at a 100km with a bit more throttle
response, yet have
more top end suck on full throttle upto 7000 RPM plus which is about as
good as this motor will do. Besides who wants to spend a bucket full of
money to get an extra 10 hp with dual carbs.
Most guys run thier motors 80% of the time between 3-5000 RPM and only a small
percentage in the 6-7500 range.
Fit a air cleaner double the stock diameter on a made up alloy base for free
air flow with a 3" flexible flutted pipe to the side air intake for cold
air induction.
Muffler
Fit a 2.5" exhaust chambered stainless muffler and resonator, although
2" will be ok.
Oil
I found 50/70 SAE is ok, theres no need for a cooler, but one was fitted,
also cut some sheet metal to baffel the sump and pop rivet it to the existing
windage tray to control surging and oil surface frothing.
Timing
Distributor setting is at 10-12 degrees should work better at high RPMs
This engine should be safe to 7500 and give good performance around
the street, however track work may require more work due to the higher
loadings placed on the motor for longer periods.
COOLING
Recored 5 tube radiator was fitted since the old one was at its life
limits, full 35mm copper water tubes run to the rear in the standard position
except at the engine bay run together to the gearbox side to the
position of the inlet/outlet on the motor.
A manual overider fan switch is installed since the motor usually runs
at 80 deg. instead of the 90/95 cut in/out which was thought to high. Install
a cut in fan switch.
BRAKES
The master cylinder push rod shaft in the pedal box was was threaded
for adjustment to reduce the slack pedal feel for the clutch and brake
with the result of a more positive response.
Rear brakes are standard with super soft pads which seem to last 2-1
to the front on normal city driving, hand brake standard.
WHEELS & TIRES
For 5 years now the car has been running front 215 x 50 and rear
235 x 50 tubeless Bridgestone 340 Eagers with raised lettering on Momo
rims which one had to be straightened, the rubber is in line with the guard
so should be 'legal' in most places. The set up is good and looks mean
with just enough guard clearance, however a slight coaxing of a hand pull
on the rear guard by about 5-10mm and the removal of the hub spacer is
required since its not used on all cars. There are some views the rear
tyres were oversize but this is not the case since some 50,000 km and 2
sets of tires later the reliablity is excellent, in fact they seem to be
safer since the darn things will still run on 5-8 psi on a puncture.
The wheels have been sand blasted, painted black centers with polised
rims and chrome nuts, contoured mud flaps all round.
SUSPENSION
Stock springs with the front approx 40-50mm lower by fabricating
a extended bracket on the lower strut bolts thus retaining maximun number
of coils for soft travel rate, shockers are after market standard gas refills
inserted, which are adequate for 10 years life. Corning is excellent with
the large tyres, thus a roll bar is not required.
TRANSMISSION
Stock Fiat 4 speed is good for 'boy racer' day to day driving
should give better torque than the 5 speed.
Normal driving will transfer approx only 50-100 hp (2000 - 7500
rpm) through the gearbox which out perform most standard cars.
Clutch used is a rebuilt stock unit on the belief its better to burn
out a clutch than a gearbox, the clutch retains all the power unloading
features of torque springs and waffer centers to soften power transfer
to the transmission as opossed to racing clutches, to date the clutch has
done well, but needs replacing every 5 years approx.
The clutch is bolted to a lightened steel fly wheel for better response.
Gearbox oil level is maintained at a highr level with the fabrication of a extended
dipstick fitted to the filler plug, level should be equal to the main input
bearing with a 85/140 grade hypoid oil which is a little heavy resulting
in slow changes until warmed up in the first few minutes. These gearboxes
need more oil.
Gear stick has been cut down and shortened by half. (just hack saw it
off and stick the knob on)
PERFORMANCE
Pperformance is likely to be satisfactory, more drivable, tractible
around the city but most of all retaines good milage.
INTERIOR & TRIM
The body is a stock standard 1978 Fiat X19 - 1300cc
The center console housing the ash tray and vent controls was discarded
and the console uprights cut of level with the central tunnel. A new tunnel
console was fabricated and finished in red vinyl deck and black carpet
side with polished aluminium bullnose beading around the edges.
This matches the door trim of upper red and lower black carpet with
a polished alloy trim separating on the line of the armrest at that angle.
Door internal lock buttons deleted.
The treatment continues to the new customised dash which is fabricated
from timber, ply wood and alloy. Starting on the facia a strip of 1/2"
ply was used with cut outs for the 2 side vents, glovebox, central radio,
instrument unit; next another smaller strip of ply was used to house
the switches centrally by fabricating a 3mm alloy panel with squared jigsaw
holes for the switches to fit.
The instrument cluster is standard X19 screwed in from behind with
a semi circular cover for the showing of the gauges and warning lights.
The whole pannel is upholstered in red/black vinyl with the continuation
of the polished alloy running across the waist line of the dash, the unit
then can be fitted in place after dropping the steering column and snap
fitting the existing electrical couplings. The top dash deck is timber
bullnose 50mm wide protrudes over the facia and is covered in wadding and
blck vinyl, fitting with 2 screws to the facia.
Seats covers are black lambs wool, carpet is black wall to wall.
Hood lining is ply and covered with black diamond stitched velveteen.
Front boot interior is sprayed black acrylic and fitted with black floor
mats extending to the top of the sealing rubber, Rear boot is painted black
acrylic with black floor mats running up to the hinges and sealing rubber.
The carburetor fan is installed under the passenger dash and connected
to the windscreen demister vent blowing through a mini radiator with a
flip/flop flap for fresh air.
Heater is a electric creamic type.
WEIGHT
FOR THE 'WANNABE RACERS'
For those who want more performance, strip out the interior and replace
glass for perspex, install a aluminium boot, bonnet and engine cover, alloy
radiator, high temp poly or PVC radiator pipes, alloy muffler, leave off
the roof, take out dash and make a braket for the instrument cluster. This
should bring the cars weight down to about 600 or 650 kilos.
"Happy Hooning you petrol heads"
More tips comming.
Easy Supercharging instead of Turbocharging
A supercharged 1000cc motor is about equal
to a 3000cc aspirated
|