fter eight years of rolling around these states being pushed by a
Detroit 6V92T engine, I had an opportunity to latch on to an
Eight-Vee-Ninety-Two at a pretty good price tag. This is the kind of
machine that really flattens out the hills. All these years I've
patiently negotiated a grade or two (as most of us have) and I concluded we deserved the big machine because we were worth it!
What a simple job it is to pull one engine and install another, NOT! To summarize the installation, It cost about $1,500. in additional parts and 150 labor hours, all paid to my favorite mechanic, Martin. What could be more simple than pulling one engine and replacing it with another? The only difference between the two engines is the 8V92 is about 7 inches longer than the 6V92. Happily this meant my batteries could remain in the same location and my radiator fan drive would be the same. At this point a little explanation is in order. My rig is a model 05 Eagle, but unlike most Eagles, I did away with the miter box and use a Boston Gear right angle drive to spin my radiator fan. The right angle drive is operated from a pulley extending from the engine drive shaft. In addition, I employ the space where the miter box was to locate my starting batteries. This is not an ideal location for batteries due to the heat, but frequent inspection and servicing of the batteries have yielded satisfactory results.
A well installed motor in an Eagle can be removed from the bus in about 3 labor hours. This means draining and saving the coolant, disconnecting the drive shaft, the throttle, the hoses, the air lines, the exhaust system, the mounting bolts and the electrical connectors. At that point the engine may be pulled with a forklift or other dolly arrangement such as an engine buck or transmission jack. It's motor mounts slide out on the two side rails ready for R & R.
The new engine I bought was a fresh take-out from a truck. The trucker had to have a Cummins. (Note some truckers hate Detroits. . . Go figure?). Since it was a truck engine, the existing motor mounts would not fit a bus frame. So, the bell housing from the old engine was removed and installed on the new motor. This effectively converted a truck engine to a bus engine. The basic difference is the location of the engine mounts and the starter location. In addition, the bell housing on my old engine was cast iron which allowed us to mount the Allison transmission with no additional supports. By way of explanation, most bell housings are cast aluminum and when an Allison transmission is attached, it is customary to add additional transmission support.
Further preparation consisted of adding my starter and temporarily removing the turbo charger. The turbo charger was top mounted, as most truck configurations are, so it had to be removed so the assembly would slide in. My bed support is framed in and the turbo charger extends above the floor line. The bed may be lifted for top access to the engine.
The Allison was bolted up with it's flex plate. . . no change there. The transmission cooler which is a simple football size heat exchanger was relocated over the Allison making room for a new muffler. My original installation did not have a muffler, only a small resonator. My friends had remarked I could be heard coming six blocks away. I used to crunch down as I went through a town hopping no one would recognize me despite the fact I was already unrecognizable. When my Jakes went on, people in their graves would sit up and take notice.
We decided, early on, to use my old radiator. I often said, most everyone I knew, with an 8-92, had fried their engine, or were going to. In retrospect and in all honesty, I must admit, this was said with a degree of envy and a lot of jealousy. At any rate, we decide to have the radiator rodded-out and acid bathed and pressure tested. I had one quote for a seven tube core to fit my tanks for $1,600., but being a penny pincher, onward we went. One other trick we used was to route each bank of the engine into it's own port in the top of the radiator, so the right bank coolant went into one side of the radiator and left bank into the other. Finally, since the radiator fan was driven with a right-angle drive, the driving pulley on the engine crank being about three inches larger in diameter than on the old engine, the fan spun at approximately 400 rpm faster than a 1:1 ratio. In other words, when I am idling at 550 rpm, my fan is spinning at 950 rpm. This sucks more air past the radiator and pulls more heat out the motor. And, as further insurance, a 1/2" diameter copper tube was pierced with tiny holes to deliver a spray of water to the radiator for evaporative cooling to carry off more heat.
The old exhaust system used to leave the turbo, duck down and forward, pass through a resonator and depart just behind the left drive wheels. The neat thing about this arrangement was I could examine the amount of smoke I left by barely shifting my eyes to the mirror. My new exhaust system curls over the top of the motor, down the right side into a muffler and finally out through my corner bumper on the curb side. It is with some frustration I look for exhaust since it is no longer on the left side of the bus and the new motor doesn't smoke. And, it's so damned quiet I am not sure it is running. With my old motor, I had two trust signals, roar and smoke. Does anyone know how hard it is to give up smoking?
I was tempted to convert to an air throttle since I had a new spare actuator. But I stuck with the old tried and true cable throttle. Martin rerouted it to giver much freedom so it is quite responsive. In the past the throttle cable seemed to hang up a little and sometimes it was like standing on a brick to get the old gal to move.. We did replace the modulator control for the transmission and now it down-shifts with authority. The cruise control was re-installed and it continued to work like a charm. I will say with authority, the King cruise control is one of the best accessories I have every added to the bus to enhance the comfort of driving a big rig.
The electrical system went back to it's original condition. The batteries were reinstalled and the alternator returned to it's old location. The engine instruments on my coach are tach, Speedometer, Pyrometer, Oil Pressure, two Engine temperatures and a voltmeter. The only problem was the tach drive had to be relocated to a blower drive from a cam shaft drive. The cam shaft locations were all used up. So, it was necessary to add a multiplier so my instrument read correctly.
The test drive was a delight; as close to sex as an old man gets. We tested it by going up a 7.5 percent grade on a 95 degree day in Southern California. The bus responded like driving a car and the maximum temperature we achieved with my foot in it up that grade was only 190 degrees. Now, I expected to romp up that grade at about 70 mph. Sad to say, I was mildly disappointed when the old gal would only do about 40 mph up that 7.5 percent grade. This ain't bad though, since with my old engine, it would only do about 30. The only problem we had on the test drive was an air compressor regulator hung up and we were not building air on the trip back. We made it safely back to the yard where a new regulator was installed. One other problem was a cold water leak which was located a few days later and corrected. I'm ready to run with the big boys now.
Engine preparation
... Bell housing
... Starter
... Power steering pump
... Turbocharger
... Alternator
Mounts
Driveshaft coupling
Cooling system
... Radiator
... - Modification
... New plumbing
... Fan drive
... Water spray
Exhaust system
... Heat control
... Muffler
... Bumper modification
Transmission cooling
Throttle
... Transmission modulator
... Cruise control
Electricals
... Battery
... Alternator
Instruments
... Tach
... - Multiplier
... Speedometer
... Pyrometer
... Oil Pressure
... Temperature
... Volt meter
Compressor
... Air lines
Generator
... Battery cables
