Hi folks. About two years ago Elmo's son Greg kindly put me in touch
with him, offering help
with my Ardun. I didn't know it then, but I soon found out that Elmo is
one of the Masters of Ardun lore in this world. So began a long series
of enjoyable phone conversations, up to the present, which I hope will
continue for many years to come.
Eighteen months or so ago Elmo allowed me to interview him for
publication, and reviewed, corrected and approved the result, so that it
would be accurate. What follows is supposed to be published in print
out West sometime, but I can't tell when, hence yesterday I obtained
Elmo's permission to present it to this List, for your enjoyment, and
the perpetuation of solid Ardun lore.
Even eighteen months ago I did not fully realize Elmo's standing in the
West Coast hot rod and Bonneville scene, and he certainly didn't mention
it, but since then I have learned from others that ELMO IS ONE OF THE
ALL-TIME GREATS. A fixture at Bonneville and the Dry Lakes since the
late '40s, six-times President of SCTA, several times Director of the
Bonneville Speed Week Meet. Highly successful with the Lattin-Gillette
team; check out the Bonneville Records held with fuel and gas Arduns in
several classes of XXF cars. To top it off, always a warm and friendly
man to all, even his competitors at a Bonneville meet!
AN INTERVIEW WITH ELMO GILLETTE
By Bill Hoddinott
Introduction. Elmo Gillette has been involved in Dry Lakes and
Bonneville racing since 1946. Lattin-Gillette has long been known as
one of the premier Ardun-Ford racing teams.
Most speed trials enthusiasts are well aware of the legendary Ardun.
Designed in the late '40s as a hemispherical OHV conversion for the
24-stud Ford-Merc flathead V-8 by Zora Arkus-Duntov, later well-known as
the Father of the Corvette, about 300 sets were made in the years around
1950. Introduced at Bonneville in '51 by C.T. Automotive, it remains a
favorite to this day.
In this interview, Elmo reveals all the secrets of building a
record-breaking Ardun...
B: Elmo, I'm grateful to your son Greg for putting me in touch with you,
because I have a new Ardun HiBoy Roadster for speed trials, and I've
been looking for advice on various challenges that come with mechanical
fuel injection and other aspects of these cars. You and your family,
with Jim Lattin, hold the Bonneville unblown Ardun gas and fuel
streamliner records at 213 and 220 respectively, among many others.
E: Sure, Bill, I told Greg to have you call me 'cause I love to talk to
fellows with Arduns about the things we've learned with ours. Everybody
has their own experience, of course.
B: What are the fundamentals of your engine setup?
E: The same basic short block for a gas or fuel engine. We use a stock
4" Mercury crank, stock rods, Ross Ardun pistons with a 12.6 ratio in a
bore usually not over 3-5/16". This gives about 275 cubic inches, not a
really big motor, but plenty big enough. A smallish motor retains more
structural strength in the block. Nowadays the existing Ford and Merc
blocks have suffered some from rust in the water jackets so we don't
want big bores. Even with 3-5/16 we sometimes fill the jackets halfway
up with the Block Rock type of epoxy to strengthen the cylinder walls,
and this seems to have no adverse effect on water-cooling for Long
Course motors. We use ordinary cast iron piston rings, and change them
often. Especially with alcohol-base fuels the rings wear pretty fast
and then lose their seal, due I suppose to the wet fuel mixtures washing
the oil off the cylinder walls. We use .010" skirt clearance on the
pistons, and get good service from them. Ross is good to work with.
B: What rod and main bearing clearances do you like to use?
E: .003" on the rods and .004/.005" on the mains. We use Torco 50 oil
on a gas motor and Torco 70 on a fuel motor. We use a preheater pad on
the oil to get it good and hot before startup. We use both wet and
dry-sump setups for the oil, and with the wet-sump we use a fresh stock
Ford oil pump with the relief valve spring stretched, and see 80 psi oil
pressure during a run.
People say there is a good deal of flex in both the cranks and blocks
with racing flatheads, maybe as much as 1/4". With all that, you need a
good deal of clearance in the bearings, and the heavy racing oils, or
the bearings just won't last. So we have found out, anyway. We rev our
motors at 5600 at Bonneville, and 6000 at a Dry Lakes meet where you
don't run as far, and they hold together pretty well for us.
With a racing gas Ardun it is well to use a steel main cap at least on
the center main, and it doesn't hurt on the front. The center main in a
hot flathead is a known weak spot because so much of the power is
handled there. With a fuel Ardun it is probably best to go all the way
with a Doug King or other center main bearing girdle. A really high
power, long distance fuel engine puts severe stress on the flathead
block center main area and the whole crankcase casting web in that area
has been known to be ripped out by the studs. Hence the point of the
girdle, which distributes the stress along the bottom side rails of the
block. Possibly this kind of failure arises from the extreme shocks and
forces of known or unknown detonation in the engine, which the tuner
should never allow in the first place because it is so destructive
generally. It must be controlled by the right percentage of nitro, the
right compression ratio, and the right amount of spark lead.
B: At Bonneville on the Long Course you run five miles wide open, and
hold full power and high revs for a long time in the three one-mile
speed traps. That says a lot for the quality of the original FoMoCo
parts. What can you tell me about your Ardun heads, and your head
gasket system?
E: We port our Ardun heads a little, mostly to improve the exhaust
ports. There's little you can do to the intakes because of the pushrod
tubes on the sides and they're plenty big enough as they are. We use
stock valve guides and valves, with never any problems. I am interested
in the future in bushing the valve guides down from the stock 3/8" with
the guide liners available now, and using a 5/16" valve stem, since the
3/8" stem is way more strength and weight than you need or want. The
lighter your valve train, the better.
The head gasket system we have developed is a dead soft .030" copper
one-piece gasket, with all the holes cut in it, with a .041" stainless
steel wire O-ring around each cylinder bore, in a groove about .020"
deep. The wire is butted in the groove, and its function is to bite
into the copper gasket to keep it from blowing sideways under the
pressure from the combustion chamber. The groove lies about 1/8" from
the edge of the bore. Isky makes a tool for people to O-ring their
blocks at home. The original valve reliefs on the flathead block come
fairly close to the cylinder bores, especially on one side. Years ago
we used to weld a little on the reliefs to give us a better surface for
the head gasket seal, but this is neither desirable nor necessary,
because if you deck the block down a little, you can widen the distance
from the bores to the reliefs sufficiently for your needs, especially
using the small bores.
We make cylinder studs by cutting and threading aircraft Grade 8 bolts,
and we like to torque our heads about 60 ft. lbs. Never had any
compression or water leak problems with this system.
B: What is your practice with your fuel system?
E: Same compression ratio fuel or gas, 12.6. It works fine on the race
gas at the Flats, or on the 50% nitro blend we use for fuel class. We
think that is enough, more manageble, and easier on parts. There are
two schools of thought on unblown nitro motors: low compression and
higher percentages, or higher compression and lower percentages. We find
the latter works best for us. We use the same original Ardun Hilborn
injectors on either fuel, with different jets and nozzles of course, and
they have a 1-11/16" throttle body, which is plenty big enough for our
motor size. Our Hilborn pump drives straight off the nose of the
camshaft, ahead of the right-angle Vertex drive. Our injectors use ram
tubes we made, with larger bells on them.
B: Can you describe your cooling system for Bonneville?
E: Our streamliner has two 20 gallon coolant tanks, located for ballast
purposes, containing an anti-freeze and water mixture to raise the
boiling point. There are no thermostats on the heads, but we have seen
as much as 240 degrees in the coolant tanks, which is why we need the
anti-freeze mixture, and we have recently gone one step further to make
the system, which previously was vented, into a pressure system with a
radiator cap. All this to raise the boiling point because if you get
boiling, the pressure can't get out the vent fast enough to keep from
distorting your tanks. The coolant is circulated by a 12V pump. At
times, we have used only a total of 20 gallons of coolant.
B: What sort of camshaft design do you prefer?
E: We have used various flat tappet and roller tappet cams over the
years. Recently Crane ground us some new, very high lift roller cams,
which I will use with bushed lifter bores and Chev long roller lifters
to get the pushrod seats up where the pushrods line up best with the
Ardun head holes. You have to use 'guide-bars' installed in your
flathead block with about .010" clearance to the flats on the lifters to
keep them lined up with the cam lobes. I fabricate the bars from
low-carbon steel stock and angle-iron pieces bolted to 1/4" studs I weld
to the ends of the block on both sides. There is little stress on these
guide-bars.
B: What ignition system do you like?
E: We've always found the Scintilla Vertex magneto, usually with fixed
timing, perfectly satisfactory. It drives at 90 degrees off the gear on
the camshaft nose, just like the late model Ford/Merc flatheads, except
that as noted we've added the Hilborn pump drive ahead of it. Using
original Ardun heads with cartridge-fire plugs (with Champion steel 18mm
to 14mm adaptors) we use 45 degrees of spark lead with both fuels. We
have modified some heads to put the plug electrodes right down on the
combustion chamber surface in today's conventional fashion, and then we
use 36 degrees lead only. We do find that when using the cartridge fire
setup, where the plug electrodes are about 1/2" up in a 3/8" or so
diameter hole, on gas the plug electrodes, even with racing plugs, tend
to overheat unless we go over-rich on the mixture, which loses a little
power. This cartridge fire system originated on the Miller and later
Offy engines from way back in the '20s.
B: Tell me about your exhaust system.
E: Two inch header pipes on a 1/2" thick steel flange plate, with the
pipes inside the plate holes and welded on the head side, finally ground
flat. The two inch (or so, can't remember right this minute) pipes
empty into a collector pipe about five inches in diameter and about 12
inches long to the outside. The ID of the pipes is bigger than the ID
of the exhaust ports, but this doesn't hurt anything. Hooker worked
this out for us with computer modeling. These systems have plenty of
strength and are trouble-free for us.
B: Mechanical fuel injection is fussy for starting. Can you walk me
through your standard procedure?
E: Assuming your metering valve and bypass jet size settings are right,
which they must be, first you prime each cylinder with a shot of
gas(same gas as you put in your truck) from a squeeze bottle into your
ram tubes, holding the throttle open, then shutting same. Maybe 1/2
ounce of gas per cylinder. Use gas to prime it whether using race gas
or nitro blends for running. Next, with mag switch off, crank the motor
with your original Ford starter on 12V until oil pressure shows on the
gauge, holding the throttle open just a little. When oil pressure
shows, flip the mag switch on, and it should start. When it does, pump
the throttle a little to help the Hilborn pump get rid of the air
bubbles in the delivery system. You should now be able to warm your
engine up.
Sometimes, however, despite many years of Hilborn experience, the motor
doesn't start up, and it then very easily wets the plugs. So you have
to pull them and start over. These problems are inherent in mechanical
fuel injection but people put up with them because at full throttle they
work great, better than any carburetor, and are easy to tune with the
bypass jet. One thing to watch out for is that alcohol-based nitro
blend fuels cause rapid corrosion inside aluminum fuel pumps and
filters, and the corrosion particles build up on the screens in the
nozzles, or clog the orifices. If a nozzles leans out due to this you
can easily burn a piston. But frequent cleaning prevents it, as does
draining all fuel after running. Gas does not show this problem.
B: What kind of flywheel, clutch and gearbox do you favor?
E: We like a custom steel flywheel that weighs about 60 pounds, which
assists our high-gear-only starts, with an 11" Long-style racing clutch
from McLeod or someone else. The centrifugal weights of this type of
clutch help it hold better on the top end, while requiring less effort
at the pedal when you are slipping the clutch to start. We've used
various gearboxes, late four-speeds or early Ford somewhat modified, but
we generally use a push-start in high gear in any case rather than going
through the gears as it saves time and effort. Our truck pushes the car
fast enough so that it can pull away in high gear and after the driver
starts the engine and pulls away all he has to do is stand on it and
steer.
B: Do you still like to get in the car yourself?
E: Sure, I still drive it myself sometimes and I love it, but my main
responsibility out there is the tuning and preparation of the whole car,
and that is enough to think about. The driver should be able to focus
on just driving the car properly, and leave the rest to someone else.
When I'm out at the Flats, I'm extremely keyed up anyhow, the whole
time. Especially years ago, but less now.
B: What has you so stirred up, the car performing in front of the crowd?
E: No, I don't think at all about what the general public thinks of it,
but I do care intensely about how it performs in front of my friends in
the speed trials fraternity.
B: Well, nowadays when Lattin & Gillette hold the unblown gas and fuel
Ardun liner records, among others, I imagine the pressure is off.
E: That's pretty much the case. But whatever we take out, we want it to
perform. The Redhead streamliner has now been retired to the
Lattin-Gillette museum in Encinedas, CA, along with some of our other
cars, and Jim Lattin's antique motorcycle collection. I felt that the
40+ year-old Redhead, which was built for Bonneville in the style of the
front motor dragster in that time by Romeo Palamides, was no longer safe
enough in the event of a crash, since an unknown amount of rust must
have affected the steel tubing of the cage and frame by now. But the
Lattin-Gillette team will always be competing at Bonneville in some XXF
Ardun class or other. We have four big Ardun race motors, and two V8-60
Ardun race motors, and we will continue to use them as we always have.
B: Elmo, thank you so much for taking all the time to share your
fascinating Ardun knowledge with us.
END
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