Crew, Friends, and the LSR List,
Since this update is going out to a wide variety of people please bear
with me. While this dragster isn't an LSR car, it is the test bed for the
powerplant we plan on eventually running in the King$ Ran$om XXF Modified
Roadster.
This car, a 1600 lb.(with driver) 120" wheelbase replica of the 1960's
Dragmaster Dart front engine rail, is powered by a 258ci (3 5/16" X 3 3/4")
1949 Ford Flathead V-8 with an Ardun overhead Valve conversion. Induction is
a 4:71 GMC blower running at 16% overdrive on a homemade manifold. The fuel
used is Methanol.
In November Son Brian and I tested the new combination at Sacramento
Raceway, making a 132/10.3 pass (mine) and a 144/9.6 pass (Brian's) before a
fuel leak put us on the trailer.
Yesterday we again traveled to Sacramento to continue the R&D with the
help of Bonneville Speed Week crewmembers Mike Gorvad and Elon Ormsby. This
time we richened the main bypass from the Gene Adams suggested .130 to a
.115, leaving all other tuneup settings the same.
On the first pass Brian experienced considerable handling problems in the
first half of the track, lifting off of the throttle 3 times, and turned
155/9.2. On the second pass we changed the tire pressure slightly and Brian
made a strong, straight pass, showing 160/8.84 on the sign board at the end
of the quarter mile. From the starting line I heard the engine backfire
loudly in the timing lights, then backfire and "pop" continuously through the
turnoff at the end of the shutoff area. By the time we reached him he was out
of the car and waving frantically while pointing to the front of the engine,
which was missing the blower snout and front gear housing of the 4:71.
Worrying about the starter sending race cars down the track with our
blower debris scattered along the route, Elon jumped into the chase truck and
roared back to the starting line to alert the officials.
We found the first pieces of the blower front gear housing about 50'
before the finish line and the blower snout, shaft, and Gilmer belt gear
about 200' past the finish line.
Brian later recalled that the last time he looked at the tach it was
between 6900 and 7000RPM, about 170MPH on the "dream-wheel". Evidently, just
before the end of the 1/4 mile the upward force on the Vertex mag pushed it
out of the grip of the slip-ring that is clamped to the front engine cover,
retarding the spark about 30 deg. This caused a blower backfire which stalled
the blower rotors when the burst-plate on the back of the blower manifold
bulged but didn't rupture as designed. The 2"-8mm drive belt was stronger
than the cast aluminum blower gear housing, which failed and gave Brian a
face full of 90w gear oil at about 170MPH. The 10lb blower snout, shaft, and
belt pulley then bounced off of the cam driven injector pump, hit the ground,
massaged three of the left side headers, and passed under the rear of the car
while doing a number on the bellypan.
After cleaning up the car today and testing the vital signs I've decided
to pull the engine, add some valve spring pressure, get the blower checked
and have a different design of "pop-off" built by my "go-to" guy in
Sacramento, Mark Hall, and fabricate a support from the blower snout down to
the manifold. The 5" snout evidently puts too much strain on the GMC front
gear case.
All-in-all it was a good test session. Brian said that he'd never felt
anything like the "kick-in-the-pants" that blower gave him at the top-end.
With the short wheelbase Dragmaster we'll never get the results we got with
the bigger normally aspirated Ardun in the first 1/8 mile of the track. The
second 1/8 mile was evidently pretty awesome.
Our plan is to get the chassis and headers repaired, freshen-up the
engine, check the blower, fabricate a snout support, replace the broken
blower housing, and possibly complete the testing later next year in
preparation for running the blower at LSR events in 2002.
For 2001 it looks like the plan is to get the John Kilgore close ratio
gears installed in the C-4 this winter, install the backup Fuel Ardun in the
Modified Roadster for Muroc (If it becomes a reality with SCTA), and
hopefully have the Jimmy Stevens inspired Ardun ready to run for the El
Mirage XXF/GMR record in May.
Jimmy feels that we can go 200MPH on gas with King$ Ran$om at Bonneville
and is calling the shots on the engine to make the attempt with.
Ardun Doug King
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