Do you guys know of any other bus that uses the Boston Gear angle drive like Prevost uses for the fan drive.I want to convert my Eagle to a belt drive for the fan and do away with the mitre box to gain a little more fuel mileage good luck and thanks
I thought that the fan drive on Eagles were already belt driven. If hydraulic, then it probably is thermostatically controlled. Take my advice and leave well enough alone. The engineers who designed the bus in the first place know a whole bunch more then we do. If it works, leave it alone. Besides, it won't change your fuel mileage much, if any at all. Several ways of getting better fuel mileage-go to smaller injectors on the engine; accelerate at a slower rate; cruise on the highway no faster than 55mph. The rule of thumb in the trucking industry is for every mile per hour over 55 you loose .1 mpg. For every mph over 65, you loose .15mpg. So the difference between cruising at 55 compared to 75 can mean as much as 2.5mpg. Now that's a sizable fuel mileage change. Good Luck, TomC
The old PD4501 Greyhound Scenicruiser had this type of a gear box for the fan on the radiator and A/C condensor.
jlv :P
TomC, the engineers that design the system left a lot of room for improvement.Eagle are not driven directly from the engine with belts.
They are driven from the front of the engine with a shaft and coupling going into the mitre box with a shaft on each side and another to back on 8v's mitre boxes one shaft goes to the AC the other goes goes to a distribution box to run the alternator and fan that is where your belts start separate belt for each.
The mitre box is a power stealing piece of equipment the guys from Eagle told me it robs 38 hp with a 32 inch fan.
Hydraulic is not the answer for me either doing the calculations for my setup would still be in the 28 hp range for a fan easy to figure Pressure x Gpm divide by 1714 = HP
my solution to the problem and I may wrong is to use a angle drive, belt driven with a 2 speed air clutch then I will be in 17 Hp range according to the guys at Horton
Thanks for the info JLV if your not busy drive down to Breaux Bridge and attend our rally May 1-4
less Hp useage to me is better mileage anyway I figure it good luck
You probably won't want to use a PD4501 gearbox. Most are shot & in dire need of new gears, shafts, bearings, & seals. Ohio Gear made the gearbox, but I was quoted over $1500 for just the gears & shafts! :o
Then there is the damper that mounts the fan to the gearbox output shaft . . . .
The Prevost gearbox & fan setup is likely the best place to source parts, lots more of them made & more recently too. ;)
If diesel = $2/ gal & you got 7 mpg (vs 6.5 mpg before), it will take 4550 miles to save $100 in fuel . . . If you put enough miles on your bus, it could eventually pay for the change.
Kyle, thanks for info about the 4501 gear doesn't sound like the one I would use.The mitre box on a a Eagle cost around 2 grand to rebuild and they don't last for ever and most leak a little.
Then there is the coupling that needs replacing ever so often that most people don't pay any attention too till it's to late but I replace mine every 5 years and it will always show wear it cost over 200 bucks to replace.
I drive 10,000 plus miles per year on the average so I am thinking it may not be a bad deal for me where I can turn the fan on low or off in cooler weather and save more.
good luck
Just shooting from the hip here. Will a Bush Hog mower drive work and would it hold up under these conditions?
There's always the old Corvair type belt drive.
See, you can come up with all kinds of great ideas when you don't know what you're talking about.
Gear box orientation matters. The oil level/ spray inside the box may or may not allow you to rotate it sideways.
~20+ hp thru a belt over twisted pulleys may be doable, If I were to do it, I'd make belt guides to make sure the belt couldn't jump off the pulley. You'd need to be careful that the belt laid in the pulley properly to avoid premature belt failure . . .
Hey Clifford, What are your thoughts on the 'corvair' style fan drive?
17 vs 38 HP is a substantial savings. We should all be so lucky to have this as a fix. I have a serious comment but I want to start a new thread for it. Cliff, your numbers are VERY interesting to me.
John
At one time i saw a 1968 flexable with electric fans 3 i think cooling the radiator.
How does that type of set help or hurt HP or MPG. Is this a option for cooling a bus.
i saw a place on the net that sells a hydraulic fan set up, that is driven by a pump with a electric clutch that engages when needed, would that be a good idea ? the kit sells for around 2500.00, the sales guy said he has sold a lot for the mci busses and hasnt had any troubles, what are your thoughts?
The electric fans will only produce a fraction of the horsepower that goes through them. The same thing will happen with hydraulic drive, except that it will be easier to develop enough power using the hydraulic drive.
You should figure that if everything is done just right, you will lose about 25% of the power you put into either system. On the other hand, you can run mechanical drives with 3 to 5 % loss in them. And you shouldn't have any trouble making them powerful enough to cool the engine.
In any case, propeller type blowers are not very efficient. I'm pretty sure that's one of the reasons that MCI used the centrifugal blowers.
For what it's worth.
Tom Caffrey
I purchased an angle drive box from a local vender the brand is Hub City Gear it works great. I think it was around $600 Chris