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BME Wrist Pins: Born in NASCAR
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The wrist pin is,
arguably, the most highly-stressed part in a racing engine. The
expansion of burning gases in the combustion chambers applies
tremendous force on the piston tops. That force is transferred to
the connecting rod via the wrist pin, a short-length of
thick-walled, tubular steel. Inside an 850 horsepower, NASCAR Sprint
Cup engine running at 9000-9500 rpm, a crushing force of six tons
hammers each wrist pin about 77 times each second. This punishing,
cyclical load lasts up to 600 miles in some races. Wrist pins in a
Cup motor are subjected to unbelievably high levels of both bending
and radial stress which they must sustain for a considerable period
of time.
The BME Wrist Pin,
introduced in 2000, grew out of Bill Miller’s three-step business
strategy: 1) make the parts racers need, 2) sell them at a fair
price and 3) engage in a ruthless pursuit of quality. Bill Miller’s
idea: manufacture a wrist pin which could both meet the difficult
durability challenge of Sprint Cup racing and be a better value. |
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The BME Wrist Pin line was
begun in response to the hard-edged competition in NASCAR
racing. Sprint Cup teams wanted a wrist pin with
uncompromised strength but at a good value. Image:
Goodyear/Aaron Vandersommers. |
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A BME
Wrist Pin begins with 9310 vacuum-arc-remelt (VAR) steel, a raw
material with the purity and strength necessary for wrist pins used
in Sprint Cup and other gasoline-burning race engines but, also, a
material which is more cost-effective than some of the exotic steels
used by other wrist pin manufacturers for those applications. A VAR
steel is melted twice. Conventional foundry processing produces an
ingot of 9310 steel. This ingot is placed in a water-cooled, copper
crucible. The crucible is sealed, a vacuum is applied, then a
high-amperage, DC current is connected to an electrode inside the
crucible. Arcing between that electrode and the ingot remelts the
steel. The vacuum prevents contamination resulting from molten steel
reacting with the atmosphere and any gas bubbles released during
remelting are drawn off by that vacuum. The result is an ingot with
outstanding internal structure and excellent chemical homogeneity.
The foundry then processes ingots of 9310 VAR into round, bar stock.
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The strength and
durability of a BME Wrist Pin comes just as much from the processes
used to manufacture it as it does from its raw material. A section
of Bill Miller Engineering’s Carson City, Nevada factory is equipped
with CNC turning centers devoted solely to Wrist Pin production. The
CNC’s cut 9310 VAR bar stock into sections, the inside and outside
diameters are precisely machined and the ends are cut and ground.
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Visually, the most unique
feature of a BME Wrist Pin is is mirror finish, applied by
special lapping machines. Both the outside and the inside of
a BME Pin are finished in this manner. |
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Not only does BME use costly
mechanized lapping processes but the final quality control
step in production of a Bill Miller Engineering Wrist Pin is
checking by laser measuring equipment. |
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After
rough and final machining in the CNC’s, BME applies a unique, mirror
finish to the inside and outside surfaces of each Pin using special
lapping machines. Only half a dozen manufacturers in North America
have such equipment and because of that, BME Wrist Pins for Sprint
Cup engines have a mirror finish which is an unusual, high-quality
feature. |
Wrist Pins for Racers
Stock car racing is not the only
form of competition in which racers can gain reliability and durability from
Bill Miller Engineering 9310 VAR Pins.
While this
product was originally designed with NASCAR in mind, they’ve become quite
popular drag racers who
run in Pro Stock, Pro Mod, Comp Eliminator, Super Stock or other types of
racing where normally aspirated, nitrous oxide injected or even supercharged
gasoline-burning race engines are used.
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BME, also, manufacturers
a line of Wrist Pins for alcohol-burning and nitromethane-burning,
supercharged drag race engines. Remember that force on the piston
top we talked about earlier? In an 8000-hp, supercharged,
nitro-burning engine in a Top Fuel Dragster or a Funny Car, that
force is even more extreme, perhaps as much 50 tons.
There are very few raw
materials with the incredible strength required by wrist pins in a
blown-fuel, drag race motor. BME Pins for nitro-burning,
supercharged engines are made of VascoMax C-300, an exotic,
costly,
nickel-cobalt-titanium steel “superalloy” with very high ultimate
tensile strength (294,000 psi) and an extreme fatigue endurance
limit (one billion cycles at 125,000 psi). Like Bill Miller
Engineering’s 9310 VAR Pins, the VascoMax C-300 Wrist Pins receive
BME’s special manufacturing processing which gives the O.D.s and
I.Ds that distinctive, high-quality, mirror finish. |
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BME Wrist Pins have given seven-time NHRA Top Fuel Champion
Ton Schumacher an extra margin of reliability in his
8000-hp, nitro-fired engine. Schumacher's 2009 title was his
sixth consecutive championship. He's shown here in the 2007
spec. U.S. Army/Don Schumacher Racing Dragster. Image:
autoimagery.com |
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Since it’s introduction in
2000, production of the BME Wrist Pins has ramped-up rapidly
as its acceptance by racers has grown. |
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In the short history of
Bill Miller Engineering’s Wrist Pin line, success has come quickly.
In the last three years, the NHRA Full Throttle Drag Racing Top Fuel
Championship was won by Tony Schumacher driving the U.S. Army/Don
Schumacher Racing Top Fuel Dragster. Inside the Army car's engine
are BME Wrist Pins. In '09 Robert Hight won the NHRA Funny Car
title. In ‘08, Cruz Pedegron won it and his brother, Tony, won the
Champion ship in ‘07. All three of those racers chose BME Pins. It
wasn’t just the champions using the Bill Miller Engineering Wrist
Pin. In 2008 and 2009, at least 80% of the top ten in both Top Fuel
and Funny Car had BME pints in their engines.
Who are all those blown
fuel racers using BME’s VascoMax Pins? In Top Fuel: Larry Dixon Jr.,
Antron Brown, Cory McClenathan, Brandon Bernstein, Morgan Lucas,
Shawn Langdon and Six-time IHRA Top Fuel Champion and NHRA
competitor, Clay Millican. Of course, Bill Miller uses his own Pins
in the Top Fuel car Troy Buff drives for him because the best way to
test the best wrist pin in drag racing is to run it in your own T/F
car. Funny Car racers using BME Wrist Pins are: Ashley Force-Hood,
Ron Capps, "Fast" Jack Beckman, Del Worsham and, last but not least,
14-time NHRA Funny Car Champion, John Force.
With the Bill Miller
Engineering Wrist Pin, once again, it’s clear that BME’s ruthless
pursuit of quality pays off with a product that is reliable, durable
and performs beyond the expectations of the many stock car and drag
racers who win with them. |
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