Clutch and Transmission With the engine assembly nearing completion, the next major steps are the installation of the high-performance clutch and transmission. Because the 427 is a high-revving performance engine, capable of delivering 475 horsepower, it's important that the engine be matched with a stable, high-end transmission system to connect all that horsepower the road. The transmission system used in conjunction with the 427 is a close-ratio, fully synchronized four-speed. "Close ratio" refers, not to the shifter throws, but to the percentage of change during shifting. This type of transmission maintains the rpm's in a narrow range while proceeding through the gears, keeping the engine always working in its "power band." The clutch assembly consists of an oversized clutch and pressure-plate and a heavy-duty fly wheel. To begin the installation, the engine is transferred from the engine-stand to a hoist, then moved onto a table, equipped with a block-plate, for easier access to the backside of the block. Wooden blocks are used to bolster and secure the engine to provide a stable working platform. The rear of the crank is checked for any burrs or debris that might prevent the fly wheel from mating up flatly against the flange. Thread-locking compound is added into the threaded holes (figure A) to ensure that, once the bolts are installed , there is no danger that they can later become loosened thereby releasing the flywheel . Next, the block-plate is installed (figure B). This particular block plate is constructed of heavier steel than was used with the original engines. The heavier construction provides an added measure of safety in the event that there ever were a clutch failure. With the block plate in place, the flywheel can be installed (figure C). The flywheel has been pre-balanced with the crank, and is indexed so that it can only be installed in the correct position. New fasteners will hold the wheel in place , and will be torque-tightened (using the stepwise technique) to the recommended specs . Torque values such as these, which are important in any engine assembly, are especially important in a high-performance engine. Once the flywheel is properly secured, the clutch and pressure-plate are installed (figure D). A useful tip for properly installing these components involves using an old transmission input-shaft to align the clutch and pilot bearing. This technique will help simplify installation of the transmission. The bolts securing the pressure plate are also held tight with thread-locking compound and are torque -tightened to spec. The input-shaft is removed to ready the clutch assembly to receive the transmission. Next, the blow-proof bell-housing (or "scatter shield") is installed over the clutch assembly (figure E). As with block plate, this updated component is of a heavier construction than on the shields originally installed on these engines. The originals were made of cast-iron or aluminum, while the updated version is stamped steel. The extra sturdy construction is a protective measure for added safety in the unlikely event that the flywheel, clutch or pressure-plate should ever break free. The four-speed transmission is prepared for installation. This particular transmission incorporates an upgrade from the original in the form of a hydraulic throw-out bearing . This design is more compact than the original and allows the moving parts of the assembly to be housed inside the scatter shield. This attribute is particularly helpful for replicar applications since, in most reproduction vehicles, there's little room between the engine and frame for linkage. The compact design makes for a cleaner installation overall. Once the transmission is prepared, it's mated to the housing and clutch assembly (figure F). The drive-shaft is slid into place, and all components are checked for proper range of motion. The completed power-plant -- the engine and transmission assembly -- is now ready to install into the completed chassis. Special thanks for this episode of DIY's Build a Kit Car Unique Motorcars
Gadsden, AL Mid-South Gear Specialists
Knoxville, TN Curt Scott
Crown Communications, Inc.
Santa Clarita, CA Ted King
Knoxville, TN Dan and Sarah Fowler
Knoxville, TN Tony Lewis
Knoxville, TN B.J. Auto
Knoxville, TN
RESOURCES :
cobracountry.com
Premiere online resource for all things related to CobraB. reproductions. Established by enthusiast Curt Scott, and maintained by Crown Communications of Santa Clarita, CA, the site contains news, articles archives, a directory of Cobra-replica specialists and manufacturers, aftermarket sources, announcements of upcoming shows and rallies, listings of Cobra clubs, links to other Cobra sites, and more.
Cobra Country
Website: www.cobracountry.com
Unique Motorcars
Unique Motorcars
(Unique Cobra Specialists)
Manufacturers of high-quality Cobra® replicas since 1977, Unique Motorcars also maintains an informational and well-illustrated web site providing information about their Cobra reproductions and related products. Assembly manuals for their kits (including the one used in DIY's Build A Kit Car workshop) are available on their site.
230 E. Broad Street
Gadsden, AL 35903
Phone: 256-546-3708
Web site: www.uniquecobrareplicas.com
Information also available at:
www.cobracountry.com/unique
The Cobra Story: A Man, His Dream and His Automobile
Author: Carroll Shelby and John Bentley
1965, Trident Press
Carroll Shelby website
Shelby Cobra: The Shelby American Original Color Archives 1962-1965
Model: 0879387572
Author: Dave Friedman
(1994)
To order this title from Amazon.com, click here.
Motorbooks International (MBI Publishing)
Essential AC Cobra : The Cars and Their Story 1962-67
Model: 1870979850
Author: Rinsley Mills
(1997)
To order this title from Amazon.com, click here.
Motorbooks International (MBI Publishing)
Shelby Cobra Gold Portfolio, 1962-69
Model: 1855200236
Author: R.M. Clarke
(1990)
To order this title from Amazon.com, click here.
Motorbooks International (MBI Publishing)
Carroll Shelby's Racing Cobra
Model: 0850454573
Author: Dave Friedman and John Christy
To order this title from Amazon.com, click here.
Motorbooks International (MBI Publishing)
Shelby's Wildlife: The Cobras and Mustangs
Model: 0879380454
Author: Wallace A. Wyss
To order this title from Amazon.com, click here.
Motorbooks International (MBI Publishing)
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