PREPARING A FORD ZEPHYR Mk II FOR RACING
Part 5 in a continuing series
First, I shouldn't try to do mental arithmentic at the end of a long,
hard day. The AUD2000=USD1480, not 2800 as I said in the last isssue.
The Eastern Creek Historic Meeting was a record - 410 entries! The meeting
celebrated the 50th Anniversary of the founding of the Vintage Sports Car
Club of Australia. A glance through the entry list (for LBC slant) shows:
(excluding the various racing car classes)
LOTUS Elite, 11, 15 Elan 23 T/C 20b Super7 Europa S4FHC Cortina
MG PA '49 TC many A's B's Midget TF TD Magnette RV8
TR 2 3 3A 4 GT6 7 8 2000
AH Sprites Mk 1, II and III 100/4 6 100S
Jag D-type!! Etype XK 120, 140 150 Mk I and II sedans
Sunbeam Alpine
Elva Courier
Morgan Plus 4
Daimler SP250
Jensen Interceptor FF 4WD
Sedans included BMC B-series variants such as Morris Oxford, Austin
Lancer, Morris Major, Wolesley, Bristol 403, A35, MG Magnette and
my Ford. These were in the Regularity event - there were hoards of
Minis in the Group N sedans
Thursday was final prep so I took a day off to sort out a few things. The
carbies (3*1.75" SUs) were close to the extractors and fuel was vaporising
in the float bowls if waiting at lights for any extended period. A friend
recommended Thermo-Tec tape to cool things down. 3 hours to take carbies
off, wrap extractors, fit clips, refit carbies and throttle springs. Adjust
the brakes, finish mounting the wiper motor etc etc.
Friday was private practice day. My friend had booked a garage which holds
3 cars and invited me to share it. Its the only way to fly!! Power, light,
water, access to pit lane, great!! Beats roughing it out in the paddock,
putting up with the rain, heat, on-lookers etc.
Up at 6, quick breakfast and out to the track, arriving around 8. Our
practice sessions were scheduled for 9 and 12. We went out in single file -
I'd never driven the circuit so took it steady for the first 1-2 laps then
thought I'd give it a bit of stick. Leading up to the main straight is
a constant radius lefthand bend that goes on for ever. The straight goes
downhill levelling out at the bottom into a left hand sweeper which
separates the men from the boys ie do you brake or push on through?
Anyway, I entered the straight and hit it. Blah-h-h. Max 4000rpm. Hmm
What gives here? Circulated around and it seemed to get better around
the back of the circuit but back in the main straight, nothing. After
a few laps of this I thought I'd better investigate, so pulled off.
Nothing obvious, but the floatbowls were warm, maybe the fuel is still
vaporising.
The second session was the same. We'd had a fairly heavy downpour during
the morning and the track was quite slippery. I took it steady, feeling
how the car responded to throttle and wheel. It wasn't bad really. In
fact I started feeling quite confident that this was a piece of cake ---
then I executed a perfect 360, finishing up in the middle of the track,
thankfully not off it. An observer thought it was very funny. He said-
'The wheels stopped turning, the car was stopped, then the body gave a
great shake as if it had had a big fright!'
Top gear down the straight was the same, so again I came in early.
Convinced that it was heat on the carbies, I thought I'd get some Alfoil
to wrap around the floatbowls. In the supermarket I saw these thick Al
BBQ trays - great, just what I wanted, so I wrapped them around the extractors
and tape.
Out on Saturday morning, again arriving around 8 for a 10:10 official practice
session. First lap was steady while sorting out traffic, but down the
main straight, b-l-a-h-h-h-h! SH*T!!! Now what?!?
Various opinions were offered - some sounded plausible, others, well ...
The first Regularity Event was 1:30. My only recorded time in practice was
2m46s. The BMCs were doing around 2m38s - 2m40s. I nominated 2m35s, hoping
the problem would clear itself. Again, no power down the straight, and
gradually getting worse as time went on.
It definitely felt like it was starving for fuel. Checked the glass catcher
bowl - there was grit in there, cleaned it out and checked to see how long
it took to refill. It took about 10 seconds to fill. Maybe at full revs
with three hungry mouths to feed, it just wasn't getting enough. I knew
a friend who lived not far from the circuit had a spare electric pump
so I went and got it, some hoses, clips etc. Back to the circuit and with
some help, soon had it fitted in series with the existing mechanical pump.
Went home and filled up with petrol. The circuit is about 50km from home
and with running about plus track time I was using quite a lot of juice.
Sunday morning was fine and sunny. With the new pump I was confident! I
nominated 2m30s. The start was single file, fastest qualifiers out first.
As my time was 2m46s I was with the slower cars. This posed a bit of a
problem as the circuit doesnt have too many passing opportunities apart
from the straight. Anyway, down the straight and YES!! 5000rpm in top -
150kph. Took the sweeper at the bottom with a trailing throttle around
140kph.
I was happy at last, even though I didn't have full throttle, I had enough
power to get past a lot of traffic. I wasn't worried about the Regularity
score, I just want to go flat out!! I had a ball - the old beast still
understeers pretty fiercely, but I manhandled it around the hairpins, through
the turns, great fun. I came back to the pits smiling for the first time
all weekend.
Times were 2:33 2:30.7 2:28.5 2:30.7 2:27.6 2:25.8 (the last was a clear
run with no traffic to hold me up). I was having a bit of a dice with a
Bug_eyed Sprite who did similar times, good fun indeed.
You can imagine how I felt in the last event, convinced we finally had it
beaten, when the same bloody thing happened! No power again! I struggled
starting with 2:27.9 but finishing with a 2:40. The bug-eye got down
to 2:23.9. I'm sure I could beat him with full power. When I got back
to the pits I noticed the centre bowl had petrol on it so it must have
been flooding. The car certainly felt different, more 'lumpy'.
So back to the drawing board. Theories are:-
1) Blocked fuel line that passes enough for road use but not enough for
racing speeds
2) Flooding from too much pressure, so one carby not working
3) Level of fuel in the tank
4) All of the above.
It could be a blockage which with not enough fuel, just cant get enough
through. This would explain why it ran fine on Sunday morning with
about 3/4 tank while other times it was 1/2 or less. It might also
depend on where the pickup is in the tank and the fact that there is an
uphill climb then constant lefthander that pushes the fuel to one side
of the tank, enough to starve the carbies for a while. The pump then
recovers on the back of the track.
I plan to run a new line from the electric pump direct to the carbies
and see how that goes. The problem is that it only manifests itself
on the track and its a bit hazardous to test on the road. Even tuning on
a dyno might not show what's happening.
paulr
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