1947 Flxible Clipper Bus Allison 1000 Transmission Conversion

1947 Flxible Clipper Bus Allison 1000 Transmission Conversion


Unrestored 1947 Flxible Clipper 29 passenger coach. Bought new by Warner Bros Studios Burbank for fleet service. Seated coaches of this vintage are very rare and this one is very solid. It is stored inside. As viewed through rear luggage bay door with load floor lifted back on hinges. Spicer 3541 4 spd w shift tower hanging. Driveshaft is removed. Previously welded flywheel is unusable. Note the round SAE#3 round flywheel housing. Starter nose is on lower right. Transmission out. This GMC engine has almost 500K miles. Compression test yielded 145-150 psi after 5 crank rotations. First crank rotation goes right to 90 psi. Pilot bearing fell on the floor when trans was slid back. It supposed to be a press fit. Rare cast iron 13 inch pull style GMC pressure plate. The GMC 401 M engine is from a 7500 series 1966 GMC truck. The engine, flywheel housing and clutch assembly was slid into position in the early 70s. The conversion was done by WB to replace the anemic straight 8 Buick engine. It was all bolted to the original Spicer trans. 13 inch disc with riveted hub. Not much lining left. The 4 speed is a very short unit at 18 inches from front flange to u joint center on driveshaft yoke. Empty flywheel housing. The Allison 1000 measurement is 31 inches. So the engine will need to be slid rearward as far as possible to get a driveshaft with an acceptable angle. Motor has to come back towards bumper. Requires removal of center bumper assembly and reinforcement. Removing skins on either side of license plate exposes 4 1.5 inch nuts. The nuts are self centering like a lugnut. This center piece is structural and very heavy duty. 22 inch fan blade with an aluminum hub and plastic fan blades was redrilled for the 401 waterpump a couple years ago. Also did an alternator conversion. Pulls a lot of air down from the roof scoop. Radiator is above the engine. The crossmember behind rear bumper was the forward mounting point for the old Buick 8 and will be removed. Sheetmetal pan under rear bumper that is part of exit air aspect of th air flow. It channels the air that is pulled through the shroud opening downward and back towards the rear of the bumper. Fan shroud system with hinged lid. Lower is removable. Radiator is above the shroud. Copper air lines have to be stretched. And fuel line. Exhaust intermediate pipe will need to be replaced to line up with muffler after engine is moved. Cannister beind pipe is the oil filter cannister. NOS starter I found on Ebay a couple years ago. Remote shift rod Ujoint at shift tower. This rod extends forward and is supported by greasable carriers. The rod occupies a space next to the center aisle of the bus and attaches directly to the floor shifter. Rod is probably 25 feet long and is soild steel. The transmission feels like it is right under the shift handle. Small rod with clevis is the throttle linkage. Pivoting horseshoe assembly operated the clutch throw out fork in bellhousing. Shift tower removed and upside down. An impressive piece of engineering that worked amazingly well. Driveline sits on a cradle assembly with a left and right side rails with crossmembers It is side bolted through the bus frame rails with 10 1/2 inch bolts. Took a lot to get them off and air tools wouldn’t fit. Couldn’t heat the nuts up either because the entire floor system of the bus is plywood. Lower section of bellhousing was completely detached. Back of bus ready to have everything moved backwards.

About the Author: Michael Flood

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