Ed LaBrush's 1952 MG TD V8 with Custom Front and Rear Suspensionas published in BritishV8 Magazine, Volume XVIII Issue I, December 2010
Owner: Ed and Carol LaBrush
BritishV8 UserID: Stage6TD
City: Willoughby Hills, OH
Model: 1952 MG TD, Chassis No. 12449
Engine: Chevrolet ZZ4 350cid V8
Built by: owner
This project began as a design exercise using the readily available resources for vehicle design.
The primary goal of this exercise was to create a vehicle that meets the criteria of a "sports car"
in the classic sense and above all is fun to drive.
Traditionally a sports car is a two seat roadster that may sacrifice comfort and convenience to increase responsiveness to driver inputs and provide high levels of braking, cornering and acceleration. A 1952 MG TD was selected as a basis for this project because the original designers of the MG had similar goals. The standards of performance have been raised in the past 50 or so years so the redesign had to reflect this, keeping in mind the MG motto, "Safety Fast".
Kinematics of the front and rear suspensions were studied with the computer program, WinGeo3 by Wm. C. Mitchell. The dynamic behavior of the chassis was further modeled with computer programs written by the owner. The primary reference for this work was "Race Car Vehicle Dynamics" by Milliken and Milliken. Virtually all of the equations in the book were programmed and used for the analysis and design of the vehicle. Guidance for the selection of the values for the tuning of the chassis was found in a variety of publications.
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Engineering Data Summary
|Front view virtual swing arm length||Front: 62.4"||Rear: 59.6"|
|Roll center height||Front: 3.0"||Rear: 5.0"|
|Scrub radius||Front: 0.07"||(Not applicable.)|
|Anti-dive||Front: 13.6%||(Not applicable.)|
|Bounce mode natural frequency at wheel center||Front: 1.12 Hz||Rear: 1.05 Hz|
|Chassis Gradients, estimated|
|Dive||2.6 degree/g (braking)|
|Squat||2.8 degree/g (acceleration.)|
Features and Specifications
|Engine:||350 cubic inch V8 Chevrolet ZZ4 crate motor, rated 355 hp @ 5250 rpm and 405 lb-ft of torque @ 3500 rpm.
Chevrolet ZZ4 aluminum cylinder heads and intake manifold.
Standard Chevrolet ZZ4 camshaft and valvetrain.
Holley 650cfm double pumper with mechanical secondaries.
14x3 air filter with spun aluminum base and lid, and Outerwear pre-filter.
Holley "Red" fuel pump.
General Motors HEI distributor.
|Cooling:||custom fabricated radiator with 4" thick core. (Original MG top tank, modified.)
Flex-a-lite 17 amp S-Blade electric cooling fan.
Aluminum water pump.
Coolant recovery system.
|Exhaust:||Chevrolet rams-horn manifolds (ground, polished, and plated).
2.0" stainless steel exhaust pipes.
|Transmission:||modified aluminum-case Powerglide with a 1.76:1 first gear.
(It's a manually-shifted "shorty" version with heavy duty parts.)
The torque converter has a torque multiplication ratio of about 2.2:1 and its capacity,
about 100, takes advantage of the engine's broad torque curve.
|Rear End:||modified Jaguar XKE rear end with limited slip differential and 3.54:1 ratio.
|Front Susp.:||Jaguar XKE upper control arms.
Corvette (C4) lower control arms.
(In both cases, original rubber bushings have been replaced with bronze bushings.)
The ratio of the upper arm length to lower arm length is 8.27/15.32 to assure camber gain.
QA1 model DR4855B 12-position single-adjustable aluminum-bodied coil-over shock absorbers, with spherical bearing ends.
Woodward KLM-style steering rack with monoball ends.
|Rear Susp.:||Jaguar independent rear suspension, with modified lower control arms.
(The halfshafts serve as upper control arm.)
Four aluminum-bodied adjustable coil-over shock absorbers.
Four QA1 12-position single-adjustable aluminum-bodied coil-over shock absorbers, with cylindrical bushing ends.
|Brakes:||(master) Corvette C4 master cylinder (0.875"), with stiffer biasing spring from Doug Rippie.
(front) Corvette C4 12" vented rotors and aluminum calipers,
(rear) Jaguar XKE Series Three 10 3/8" solid brake rotors and Girling calipers, inboard mounted,
(parking) Jaguar XKE handle.
|Wheels/Tires:||Wheels Vintique built-to-order 16x8 steel wheels. BFGoodrich Radial T/A tires (P225/50R16).
(Custom wheels were required to reduce scrub radius in the front suspension, and to
provide clearance for the front brake calipers.)
Original MG-TD style (stud mounted) hub caps.
GM space-saver spare, which fits front or rear, mounted under the luggage rack in the traditional manner.
|Bodywork:||mostly standard MG body panels, except for the hood and subtle humps added to the front fenders.
Frank Mount supplied the special aluminum hood top, and Ed made new aluminum side panels.
Dave Baldwin helped Ed press 244 louvers into the hood assembly.
Ed custom-fabricated the fender humps to clear front suspension components.
A custom fabricated scoop was added under the front valance for a transmission cooler.
Firewall, dashboard, bulkhead, tunnels and floors were all custom fabricated.
Bob Gecsi provided the polished stainless steel grille.
The car is painted MGB "Inca Yellow".
|Instruments:||Stewart Warner black-faced "Wings" style instruments in a custom engine-turned aluminum panel.
(The electronic speedometer is driven by an ABS reluctor wheel in a front wheel hub.)
Lightweight gear-reduction starter.
Optima Redtop Spiralcell battery.
|Lighting:||front side light sockets have been modified to receive amber #1157 bulbs.
The rectangular tail lights have #2057 bulbs.
The auxiliary tail lights have LEDs with #1157 sockets.
|Weight:||2270 lbs, with 52.7% on the rear wheels. (The wheel base is 94 inches.)
|Performance:||0 to 60 mph in 4.5 seconds, and 0 to 85 mph in 7.5 second on BFGoodrich Radial T/A tires.
(Acceleration is traction limited, so stickier tires would improve these figures.)
Braking and cornering performance haven't been measured.
|Completed:||running since 2008. Has been driven about 5000 miles so far, as of October 2010.
The Chevrolet "ZZ4" 350 cubic inch V8 is rated 355 hp @ 5250 rpm and 405 lb-ft of torque @ 3500 rpm.
Holley's 650 double pumper carburetor, and General Motors' High Energy Ignition (HEI) distributor.
14x3 air filter with spun aluminum base and lid, and Outerwear pre-filter.
Ed and Dave (Pops) Baldwin made 244 hood louvers with Dave's press.
A transmission cooler is mounted underneath the license plate.
Changes were required to the cooling system, but they're not as radical as you might expect. The surface
area of the radiator is stock but a thicker (4") core was installed between the original (slightly modified)
MG TD top tank and a newly fabricated bottom tank. In the foreground, you can see that an aluminum
overflow tank has been added. Also, Chevrolet "Rams Horn" cast iron exhaust manifolds were ground
smooth, polished, and plated for Ed's MG TD.
A pressure cap was added to the radiator top tank. (Bonus points for using an octogonal cap!)
The original Morris radiator badge was polished-up and reinstalled.
Jaguar XKE upper control arms are paired with Corvette (C4) lower control arms. The length difference
(8.27" versus 15.32") assures that there's suitable camber gain to achieve handling goals. Original
rubber bushings have been replaced with bronze bushings to provide more precise handling.
A Woodward steering rack with monoball rack ends was carefully selected, and then positioned to
minimize bump steer. This particular rack has a 16.2:1 ratio. (One turn of the pinion drives the rack
1.83 inches, which when combined with the steering arm geometry results in a 16.2:1 ratio between
the steering wheel turn angle and the road wheel turn angle.)
Bob Gecsi provided the polished stainless steel grille, and Frank Mount supplied the special aluminum
hood top. (Frank's MG-TB racecar will be featured in an upcoming BritishRaceCar.com article!)
Custom independent rear suspension, featuring Jaguar components.
Ed restored and modified the original MG TD frame. The front crossmember is original, but a new custom
designed "K member" was added at the rear to carry drivetrain loads and to increase torsional rigidity.
Another crossmember was added overtop the differential to support the differential carrier.
The rear suspension is easily accessed for service. Brake pad changes will be a snap.
Four QA1 aluminum-bodied adjustable coil-over shock absorbers dampen rear suspension vibrations.
The dashboard was custom fabricated, but it's consistent with the MG aesthetic.
Glove box construction details: this is where the Grey Poupon is kept.
The lid has recesses for queueing up a flight of wines for tasting.
Note also the Jaguar XKE parking brake lever.
In process: installation of new floorboards, transmission tunnel, and driveshaft tunnel.
Gear selector, with reverse lock-out feature added. Floorboards have been finished with spar varnish.
A small custom front bumper, and beneath it custom ductwork for an oil cooler.
This photo illustrates that modern tires can look right at home on the MG-TD model.
Custom 16x8 steel wheels. BFGoodrich Radial T/A tires (P225/50R16).
A GM space-saver spare, which fits front or rear, is mounted under the luggage rack in the traditional manner.
The luggage rack folds flat when not needed for carrying a picnic basket.
Original MG TD style stud-mounted hub caps. The MG logo badges are different from what an original
MG TD would have come with, but Ed prefers the look of these.
The car's name is Buttercup, and it's painted MGB "Inca Yellow".