Performance Builder’s Guide:
Jaguar E-Type Series III V-12
By Mark J. McCourt
PhotograPhy courtesy stew Jones restorations and track time Photos
opular wisdom states that of all V-12 was influenced by the 4,994cc V-12 combustion chambers with optimally situ-
the E-Type variants built between in 1966’s stillborn XJ13 Le Mans racer. ated inlet and exhaust valves, seven main
P
1961 and 1974, the first series of This aluminum-bodied car’s mid-placed bearings and replaceable, cylinder-cool-
lighter, triple-carbureted straight-six cars engine had an 86.87 x 69.85mm bore and ing, cast-iron wet-sleeve cylinder liners.
make the best racers; the V-12-powered E- stroke, and its Brico pistons and Dykes This engine would gain fuel injection and
Types built between 1971 and 1974 were piston rings were moved in their cast- be redesigned twice before V-12 produc-
too plush, too heavy, too complex. While iron dry cylinder liners by a nitrited steel tion ceased in 1996, the first time in 1981
the Series III cars, both Open Two Seaters seven-main-bearing crankshaft and forged, when it became the H(igh) E(fficiency) with
(OTS) and 2+2 Fixed Head Coupes (FHC), polished connecting rods. Dual overhead a redesigned “swirl” combustion chamber
may have been larger and less agile than cams actuated the valves, and dry sump design, and the second time in 1994 when
their short-wheelbase predecessors, their lubrication and mechanical Lucas fuel the HE was stroked to 6.0 liters of displace-
12-cylinder engines featured impressive injection circulated the fluids. The final ment.
engineering and a torquey, smooth power results of the XJ13 engine’s tuning were
delivery, and they still wore aerodynamic 502hp at 7,600 rpm and 386-lbs.ft. of the Jaguar V-12 can withstand significant
bodywork considered by some to be the torque at 6,300 rpm. cylinder boring, notably raised compres-
most beautiful of the era. Although the Using lessons learned from the XJ13 sion and is adaptable to numerous fuel
Considered by many to be overbuilt,
steel-roofed FHCs are a natural choice for engine, Jaguar developed the Series III E- delivery solutions. Although Jaguar may
high-speed race cars, OTSs perform admi- Type’s V-12 to maintain their customary have intended their often air-conditioned,
rably with judicious body reinforcements, level of power in the face of ever-stiffer power-assisted Series III cars to be Grand
and both are virtually guaranteed to be the emissions regulations. Smooth and bal- Tourers, as opposed to the pure sports cars
prettiest cars on the track.
anced, the aluminum block and head V-12 of the first E-Type iteration, there are some
The design of this company’s road-going featured a number of performance-biased enthusiasts who feel otherwise. Stew Jones,
5,343cc, single overhead-cam 60-degree components, including high-flow, flat-top president of Stew Jones Restorations in
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EnGinE
DrivElinE
BrakEs
as fitted to a series iii e-type, the stock 5.3- stew notes that many series iii e-types were Jaguars were using four-wheel disc brakes,
liter V-12 is only 86 pounds heavier than its fitted at the factory with three-speed Borg with ventilated 11-inch front rotors, for years
4.2-liter straight-six predecessor, and uses warner m12 automatic gearboxes—he esti- before their competition, and stew feels
four Zenith-stromberg 175 cd 2se carbure- mates that half of fhc models and roughly that, if properly cooled, the stock series iii
tors. the engine in the Beast is a highly modi- a third of ots models were so equipped. it units are very capable. “the Beast uses 13-
fied 7.3-liter unit that uses an 84mm Jaguar is possible to retrofit an automatic V-12 car, inch front discs with six-piston calipers, and
racing forged crankshaft, 96mm cosworth as well as an original four-speed manual car, the rear brakes are ventilated Porsche discs
pistons, carrillo connecting rods and 1.8- with a modern overdrive five-speed trans- with four-piston calipers. the only reason
inch inlet/1.4-inch exhaust valves with .501 mission. “the most difficult part is finding i picked the Porsche discs was because of
lift. with an 11.6:1 compression ratio and six a good pedal assembly. once you get the their size and ventilation; Bob green’s Bg
44mm weber idf carburetors, it makes 600hp assembly, everything else is available new,” developments in england sells cost-effective
and 578-lbs.ft. of torque.
he explains. “tremec t5s engineered for e- ventilated rear discs and spacers in the stock
“the Beast is over the top, but there are a types by medatronics are readily available, diameter, ” he says. “there’s very little room
lot of cost-effective ways to modify the series and t5s are common and relatively inexpen- to expand brake size with the inboard sus-
iii V-12 for more power,” stew says. “with sive. the cost for rebuilding a Jaguar four- pension cage.”
the short stroke, the 5.3-liter is a durable speed is halfway to a t5 conversion!”
engine that goes and goes. But instead of the Beast uses a euro-spec XJ-s-sourced tion by rerouting the original passenger com-
trying to get more power from a 5.3, it’s getrag five-speed, three-disc tilton partment air ducts to feed air to the front
easy to increase the cubic inches without engineering carbon/carbon clutch and brakes. “Jaguar designed bolt-on ducts that
stew enhanced the Beast’s braking ventila-
a
a
giving away low-speed driveability. you can 3.78:1 ratio detroit locker rear differential. stuck out below the car, ahead of the rear
combine the longer crank of the late 6.0-liter “the Beast is a slalom/autocross/track car wheels,” he says. “on most e-types, these
engine with 6mm overbore pistons and liners that is subjected to severe 80-foot turns, and are long gone, either smashed flat or possibly
and a mild, streetable cam, and you’ll have because of its detroit locker, it could chew never installed by the dealer. i added exit ple-
a 6.8-liter making between 350 and 375hp, up output shafts. we use mark williams nums that pull air from above the rear discs
which is pretty exciting in a 3,200-pound car. hardened axles, but if you’re not building and send it through hoses that exit where
the stromberg carburetors can be made to a slalom car, this won’t be an issue, and the license plate lamp used to be.”
work very well, and two-inch sus are a mid- Jaguar’s positraction rear is quite sufficient.
level upgrade before webers.
i like running 3.54 rear gears with a five-
“e-types are notorious for overheating, speed.”
and i insist on cooling upgrades on every car
i work on, including a ron davis aluminum
radiator, electric cooling fans, a 165-degree
thermostat and an airpax commercial-level
fan switch, which fits in a special housing
that i developed. the weak stock ignition sys-
tem is cured with sng Barratt’s opus ignition
replacement he upgrade.”
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resources
stew Jones restorations
860-379-1534
www.jaguarv12etype.com
snG Barratt
800-452-4787
www.sngbarratt.com
rob Beere racing
+44-0-24-7647-3311
www.rob-beere-racing.co.uk
Chassis
saFETy
while a rigid, aerodynamic coupe is the Jim wanted his purpose-built autocrosser to
obvious base for an e-type racer, an issue of be streetable, and in that, not one that drew
helmet clearance pushed the 6-foot-4 Jim undue “official” attention to itself. with this
to choose a roadster as the Beast’s starting brief, stew and his team designed tall roll
point. with the structural stresses of auto- hoops that would clear Jim’s helmet and bolt
crossing in mind, stew’s crew heavily trussed into the car’s heavily reinforced underbody
and reinforced the car using original Jaguar structure, but are removable for street use.
specification tubing, spending 2,000 hours in the snug-fitting kirkey racing seats can be
the process. “once we got started, there was converted to accommodate Jim or karen
no point in doing ‘some,’ because everything Jones, who is stew’s wife and the expert driv-
ties together,” he says. “if a car is making er who piloted the Beast in 2006 to capture
350 or 400 horsepower, you can leave the the all-time Jcna slalom record of 38.390
chassis alone, but with 600hp, all of that seconds. those seats are complemented by
braking and cornering stress starts to twist securely mounted five-point simpson racing
hayward & scott
+44-0-12-6872-7256
www.haywardandscott.com
BG Developments
+44-0-15-2787-3716
www.bgdevelopments.co.uk
Classic Jaguar
512-288-8800
www.classicjaguar.com
Medatronics Corporation
561-743-5600
the body.”
harnesses, and a low-high interior rear-view
a number of suspension upgrades can mirror offers a glimpse at everything that the
bring a V-12 e-type into the 21st century, Beast leaves behind. the exide orbital o6 gel
and those include stiffer 7/8-inch torsion bars, battery rests behind the passenger seat.
www.5speeds.com/jag.htm
Fuel safe racing Cells
541-923-6005
harvey Bailey engineering anti-roll bars and
its capacity selected with running the lime
adjustable koni shock absorbers. “urethane rock race track in mind, the Beast’s trunk-
bushings are the buzz word in racing,” stew mounted “fuel safe” fuel cell holds 22 gal-
explains, “but Jaguar’s stock upper a-arm lons of racing gasoline. this unit was also
bushings are beautiful, and i never alter chosen for its low-profile design, which main-
them. i do use urethane in the lower a-arms, tains the car’s low center of gravity.
although i remake the inside steel shell. i run
www.fuelsafe.com
Tilton Engineering
805-688-2353
www.tiltonracing.com
really fast cars with the oe rubber Jaguar
bushings without issue. the Beast uses heim-
Mark Williams Enterprises
800-525-1963
jointed radius arms and spax shocks, and
www.markwilliams.com
while its bonnet and rear quarters look stock,
they were modified to allow fitting 18 x 11.5-
inch BBs wheels and 315/30-18 hoosier slicks,
ron Davis racing Products
623-877-5000
but we have a second set of wheels and
www.rondavisradiators.com
tires for the street. we’ve installed Jaguar-
sourced steering rack travel limiters to stop
the front wheels from interfering with the
harvey Bailey Engineering ltd.
+44-0-13-3534-3018
suspension.”
www.jagweb.com/hbe/
Cosworth Pistons
310-534-1390
Winsted, Connecticut, is one of them.
V-12 car opened his eyes to its possi-
www.cosworth.com
A Jaguar restoration specialist since bilities. “I believe in the twelves,” he says.
1977, he enjoys bringing out the Series III’s “There is a lot of competition in the Jaguar
inherent sports car character with vehicles world between six- and 12-cylinder cars,
like our feature car, “The Beast,” the Jaguar and they’re an untapped source because
Club of North America slalom record they’ve been overshadowed by the sixes
holder and track racer that his team built for so long. They have a lot of potential
for Lincoln, Massachusetts, resident Jim and respond nicely to modifications, and
Roberge. Like many, Stew was a fan of the as the old saying goes, there’s no substitute
early models, but working on a customer’s for cubic inches!”
simpson race Products
800-654-7223
www.simpsonraceproducts.com
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