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The Chevrolet-powered Rolls Royce

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The Chevrolet-powered Rolls Royce Empty The Chevrolet-powered Rolls Royce

Post by Wildcat445 Sun Jan 18, 2015 10:40 pm

We were discussing cars in another thread, so I thought I would share this experience with you.  I was re-acquainted with a client of mine from my auto restoration days this past weekend.

When I had my auto restoration shop, I had a client who was a famous female singer from the 1940's.  She and her "male friend" owned a couple old Jaguars that I would service and make minor repairs on.  This lady was a better singer than she was a driver, since I frequently made repairs that were due to her running into or over objects that damaged whatever vehicle she was driving at the time.  Her "driver" was a 1988 Rolls Royce Shadow, white with a tan padded top and tan interior, with red piping and carpet.  One Friday afternoon, this lady came wheeling into my shop, with smoke and steam just rolling from her Rolls.  Every warning light and buzzer on the instrument panel was going off.  The temperature gauge was pegged and turning right and the engine sounded like it was grinding rocks.  She demanded that I eliminate "that nahsty smoke" immediately!  And worse, the "refrigeration" (AC in Arizona-speak) had quit working.  She was "absolutely wilted" and asked that we take her home.  We investigated and found that she had "curbed" her Rolls on something, damaging the radiator, AC condenser and had poked a hole in the oil pan.  The engine was toast.  When I called and informed the lady of our findings, she replied "Then you must simply junk it, dahling."  I informed her that I could not "junk it" without a title, so she sent her "girl" to the shop with the signed title, and with instruction to dispose of the Rolls as we pleased.  She was having a new Rolls delivered that afternoon.  There was slightly over 20,000 miles on the damaged Rolls.

That Rolls Royce motorcar was powered by a 6.8 Litre V-8 of approximately 414 cubic inches, with "sufficient capacity" listed as its horsepower output.  The Rolls Royce V-8, still in use in the "entry level" Rollers got its lineage from the 374 cubic inch Packard V-8, abandoned after the Packard-Studebaker merger in the 1950's.  Rolls bored and stroked the old Packard V-8, added a full-flow oil filter, petted and polished it, added twin SU carburetion.  By the time this particular Rolls was built, it sported Bosch Jetronic fuel injection, and housed the booster pump for the strange mineral oil based braking system then employed by Rolls Royce.  "When one encounters the brake reservoir level below the sight glass, the chauffeur must find, in the spare tire compartment, the container of approved Rolls-Royce braking system mineral oil.  A wine glass full of fluid will then be required to bring the fluid level to operating capacity."  This Rolls Royce sedan utilized Harrison/Frigidaire air conditioning system, Saginaw power steering system, and a GM Turbo-Hydramatic 400 transmission, sans lockup torque converter.  This transmission, naturally, was sufficiently modified and polished so that it would be fit for Rolls Royce duty.  Its shifting operation was accomplished by a cool little electric motor setup, absolutely silent in operation.  The transmission had been modified so that its engagement and shifts were imperceptible by "milady" and her chauffeur.  Nary a clunk or any type of feedback from the transmission whatsoever.

I had a buddy in my car club named John whose forte was to repower English motorcars with American power trains.  He liked Cadillac 472 and 500 V-8's, Ford 429 and 460 V8's, Chrysler 413 and 440 V-8s, and, of course the big GM V-8's like the 455's of Olds, Buick and Pontiac, and the 454 Chevrolet Mark 4 V-8.  He would mate corporate transmissions with these engines and had been known to mix and match components to create a different experience for his monied clientele.  His specialty was Jaguar "XJ" sedans powered by a Cadillac 500 V-8 and a Turbo-Hydramatic 700-4R overdrive automatic transmission, and Holley fuel injection.  John was over to my shop one afternoon, and I showed him "my" new ruined Rolls.  We started contemplating remedial action, and settled on repowering as the most economical option.

Those big American V-8's were pricy in salvage yards back then.  They were in demand for repowering early diesel pickups and GM cars with the ill-fated 5.7 diesel from the early 1980's.  New GM or Ford crate engines were not only more expensive than I liked, but all the accessories would have to be purchased to repower the Rolls.  We had the same concern with automatic transmissions.  There had to be a way to accomplish this repower on the cheap.

Another man I was familiar with ran fleet services for a local school district.  He informed me that the school district was auctioning off 1983 to 1985 model school buses, mostly Chevrolet, GMC and Internationals.  Several of these units had nearly new, low mileage crate engines.  The auction was a couple weeks hence, so I made plans to attend.  I bid on, and bought, a 1984 Blue Bird 72 passenger school bus, powered by a 1500 mile GM/Chevrolet 366 V-8 crate engine and Allison 5 speed automatic transmission for $300.  We pulled the engine and then I put an ad in the paper to sell the rest of the bus for parts.  I sold everything eventually, including the body.  This not only got me an essentially free engine, but bought most of the parts I needed to complete the repower

We removed the Rolls engine and transmission.  The TH 400 trans in the Rolls was the one known as the "motor home" transmission with the 1 1/4 inch output shaft with bolted driveshaft yoke, and deep oil pan.  I was fortunate enough to find one from a burned motor home, free for the taking.  I took it to my transmission guy, and he completely rebuilt it, and added a shift kit.  We ultimately installed an air-to-oil cooler in front of the radiator, under the AC condenser for the transmission.  The engine bay on a Rolls was configured in a manner that made the installation of the Chevrolet school bus engine fairly straightforward.  Parts, brackets and other small items necessary to mount the alternator, power steering pump, air conditioning compressor and brake pump on the Chevy V-8 were provided by salvage yard trucks from one ton and larger.  We had to fabricate an adapter from the Quadrajet 4 barrel to the Rolls Royce remote mounted air cleaner to provide adequate hood clearance.  We used a one ton GMC truck radiator, fan and fan shroud.  An engine-driven hydraulic pump from a tow truck served to provide brake boost.  We used the bracket from a dump truck with a 366 and air brakes to mount the brake pump. All the accessory drive pulleys came from a dump truck with power steering, air brakes and air conditioning.  We changed the original Lucas alternator to a 105 amp Delco SI and used a gear reduction starter from a hotrod shop to provide clearance with the dual exhaust system.  The drive shaft turned out to be an amalgamation of Chevrolet school bus front half, mated with the Rolls Royce rear half. With the exception of the sheet metal and the front suspension, this 1988 Rolls Royce Shadow was basically a Chevrolet school bus from the firewall forward.  We used a 2 1/2 inch stainless dual exhaust system and used Chevrolet medium duty truck mufflers so it would sound more like a Chevrolet big block running than a Rolls Royce.  We added an electric booster fan for the AC condenser.  We retained the original electronic ignition from the Chevrolet engine, minus governor.

366 cubic inch Chevrolet V-8's are not known for being hotrods.  The smallest version of the Chevrolet Mark 4 big block V-8, it featured a long stroke, and was pretty much done by 4000 rpm's. In fact, they are governed from the factory at 3500 rpm.  They are torque monsters.  They power dump trucks, school buses, farm vehicles.  They are uber-dependable, economical to maintain, horribly hard on fuel.  This Rolls Royce "saloon" weighed roughly 6500 pounds, so torque was of paramount importance.  A Rolls is made to be seen, and is not intended to be a drag racing car.  The 366 "tall deck" V-8 proved to be ideal in this application.  It was sufficiently peppy to keep driving it from being boring.  Fuel economy was about 10 mpg, quite similar to the Rolls V-8.  It was not crabby about idling with the AC on.  The gear reduction starter sounded much like a Rolls Royce starter, and a gas jockey at the corner gas station could work on it.  Parts for a Chevrolet V-8 were everywhere.  With the exception of the brakes, it used real American fluids, with no exotic oil or such required.  The car still looked like a Rolls, drove like a Rolls.  The TH 400 trans we used worked perfectly with the electronic system employed by Rolls Royce.  We removed the engine management computer.

I sold this car to another client of mine.  I saw this man at the show and we talked about old times.  He still has the Rolls, and still drives it.  It has about 50,000 miles on it now.  He takes it to shows.  He has added some chrome goodies under the hood and has done a better job of detailing than we did.  I did the repower in 1996.  My friend John is still repowering Jaguars and Rolls Royce with American engines.  He currently uses GM/Chevrolet turbocharged 5.3, 6.0 and 6.2 liter V-8's and 4L80E transmissions.



Number of posts : 4893
Registration date : 2011-09-19

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The Chevrolet-powered Rolls Royce Empty Re: The Chevrolet-powered Rolls Royce

Post by jerryhawthorne Sat Jul 18, 2015 4:20 pm

Nice story WC, it sounds like you are very talented in car stuff.  Thanks for the journey! I have done a number of "restorations" on Mustangs and Porsche cars, nothing like what you took on!


Number of posts : 708
Age : 76
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