|04-06-2007, 12:15 AM||#31 (permalink)|
Join Date: Apr 2005
During the 1950s, many racers felt the 392 Hemi was the best thing to ever happen to the sport. Despite being designed as a passenger-car engine, the largest first-generation Chrysler Hemi was horsepower-maker supreme. Many manufacturers produced parts for use with the 392 and its popularity continued into the sixties.
One of the true believers in the 392 Hemi's virtues was Ed Donovan. He had raced Ford flatheads in the forties. Later, he gained valuable engine-design experience working for Offenhauser. He continued racing and was drawn to drag racing in particular. He saw the need for stainless-steel valves that could endure the rigors of racing, and began machining them at home. Slowly, he branched out, making other parts, which consumed more of his time. In 1957, he left Offenhauser and opened Donovan Engineering to devote full time to his burgeoning business.
Racing was always the vehicle for producing and testing his parts to prove their durability and performance. In 1962, Donovan built a 270 ci blown Offenhauser dragster that reached 186 mph in the quarter-mile. Still, the small Offy was never designed for such applications, and Donovan looked to the big American V-8s for inspiration.
The Chrysler 392 Hemi had become a popular engine to use in drag racing, and Donovan produced parts for this engine to meet the demand. Despite the advent of the Chrysler 426 Hemi in 1964, the 392 Hemi continued to be a popular engine on the quarter-mile strip. Donovan felt the 392 Hemi could be improved upon but the cost of doing so was, at first, prohibitive.
By the end of the sixties, Donovan's performance parts business had grown rapidly, matching the explosion of drag racing's popularity. With his resources and manufacturing capability, Donovan could realistically consider filling a need for a truly durable engine based on the 392 Hemi head but designed strictly for drag racing. Donovan had been harboring the dream of designing an aluminum engine block that embraced the advan-tages of the 392 while eliminating its weaknesses. It had to be able to with-stand the fearsome stresses imposed by the use of nitromethane, the most powerful and volatile fuel used in drag racing. With so many stock and racing parts available for the 392 Hemi, a racer could literally build a strong racing engine around the new block Donovan had designed.
Donovan spent countless hours with his small design and manufacturing team before the block configuration was finalized, and work began in 1970. All major dimensionsódeck height, camshaft centerline to crankshaft centerline, and bore-to-bore centersówere retained. Bore diameter, however, was increased from 4.00 to 4.125 in., boosting displacement to 417 ci. Instead of being a solid block, it was an open-block design using centrifugally cast chrome-moly steel wet-sleeve liners. The result was a much lighter yet stronger block, and the sleeves were interchangeable and easily replaceable. This design made it possible to develop greater horsepower than was possible before.
The second major component of the engine was the main bearing girdle, also of aluminum, that provided massive support to the crankshaft. In the stock 392 Hemi, this was a weakpoint from a racing standpoint. This new bottom-end in conjunction with the new block permitted almost unrestricted application of supercharging with nitromethane fuel.
Together, the aluminum block, girdle and steel cylinder liners tipped the scales at just under 200 Ib. Steel studs were used throughout the engine to permit repeated teardown and reassembly without galling otherwise tapped holes.
Donovan's chief engineer. Bob Mullen, produced the drawings for the engine. Arnold Birner made the precision wood patterns for the block, girdle and cylinder liners. Dick Crawford established the tooling requirements for drag racing's first aluminum engine block.
After the casting and machining procedures unique to the Donovan 417 were worked out, the engine was offered to eager drag racers in 1971. The engine made its debut at the NHRA Super-Nationals in John Wiebe's rail, setting a low ET for the racers of 6.53 sec.
Proof of the 417's viability and durability is the fact the engine is still manufactured and sold today. Donovan went on to offer an aluminum 350/400 small-block in 1978. He followed this with an aluminum-block 427/454 in 1983.
When Ed Donovan died of cancer in May 1989, his wife Kathy became head of the company, continuing the long-standing Donovan Engineering reputation.
Another brief mention of the history of block girdles:
Another brand of girdles:
Interesting commentary on both pages.
|04-06-2007, 12:34 AM||#33 (permalink)|
Join Date: Apr 2005
GIRDLE CLAIMS & GIRDLE DESIGNS
BCR-----"We have counterbored the girdle so that the stud nuts secure the girdle directly to the pan rail with only silicone. This creates an incredibly stable and ridged foundation.
No other production girdle offers this.
Then the pan is secured only to the girdle. Why did we do this? Well look at all the other girdles, they secure themselves to the motor through the tin plate pan then through a gasket then through a tin windage tray then through a gasket then through the girdle then through another gasket.
How stable can that be, it's like two pieces of bread with a bunch of peanut butter floating between each other--enough said. Other girdles work, no question but they are no where near optimal.
Why don't others do this, simple they can't make the profit by doing all that extra machining to the girdle. They just water jet everything, plate it and send it out the door. Our process involves initial cutting then CNCing all the holes and counterbores. "--------
The above is how BCR distinguishes their girdle vs. their competition.
The "peanut butter" analogy was an interesting word-picture.
|04-06-2007, 04:39 PM||#34 (permalink)|
Got it figured out?
Join Date: Feb 2004
Location: Oxford, MI
Interesting. Seems there other other innovators out there building nice products rather then wasting time doing web pages to take shots at CAT.
Let the product do the talking is what I say.
84 Regal T-type
5.31 @ 139.10 1/8t
8.19 @ 171.74 3410#
TA heads, 88 turbo
BIG STUFF 3
Last edited by Ted A.; 04-06-2007 at 04:41 PM.
|04-06-2007, 09:14 PM||#35 (permalink)|
Join Date: Dec 2001
I have to jump in - I do apologies. Our ESP Engine Girdle was the first made for the modern Turbo Buick; contrary to what some say. You do get what you pay for, as mentioned above. Our ESP Girdles are, and have been, made for over 10 years in the USA. Our hardware comes from ARP (in the USA) and the oil pick-up are made and modified in the USA. The girdles are CNC machined and ground flat to 0.003". Our plates alone cost more than the CAT kit. Now add in the ARP hardware and the rest. Our girdle never leaked when installed correctly - and I've seen people really screw them up even though they come with instruction.
ESP Twin Turbo kit
2007 GSCA 10.1 @ 133 mph
2008 GSCA 10.1 @ 136 mph (tire spin)
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