MCI cooling upgrade

[JohnEd]

Squirrel cage fans are good for moving air thru a resistance.....long pipe/duct for instance and the flow falls off gradual as the resistance to flow increases.  The fan is more efficient till you get the slightest resistance and then it craps out quick as a air mover.  Rads are open on the input side so a fan is better.  The MCI has smaller rads and relies on more airflow to get the cooling.  More airflow means higher air velocity and that resistance goes up with the square of the speed.  Soooo I can see how the squirrel cage found application in the MCI.  There must be a lot of power being used to push the air in that system.  I got a PM from a Knut that said he converted to a single high efficiency (modern?) fan, installed a shroud, increased the rad size to way overkill and drove the fan through a clutch.  Be nice if someone that really understood this stuff could publish the design and parts and costs to achieve this  upgrade.  He claimed that he had zero heating problem under any circumstance and his efficiency went up 1 MPG.

Takers?

John

[TomC]

Just look at the newer MCI's-they all have a twin radiator system-one is the engine radiator and the other is the air to air intercooler.  Both are still mounted above in the back, but operated with big blade fans with 2 speed fan clutches.  I don't see that it would be terribly difficult to switch over.  Personally-just get the biggest radiators you can find for your application, and run the squirrel cage blowers faster.  You don't put enough miles on to recoup the cost and aggrivation from switching over.  Good Luck, TomC

[RickB]

John Ed,

Having gone through my cooling system last winter I find that the problem now is it's hard to keep the darn thing hot enough. Especially since winter has started to show up in a meaningful way I struggle to keep the motor at 160 degrees I have to get my shutterstat changed out (the one I have runs a little too warm for my taste) and then I am hoping that the temp will be a bit more cooperative.


So, I agree with the earlier post for under a couple thousand dollars you can get the bigger radiators, the smaller pulley, rebuild the gearbox with the kit and speedy sleeves, new seals for around the radiator, which you will have to fabricate, I couldn't find them anywhere and you'll be good to go.

I am thinking that the system you are thinking about would be pretty spendy but who knows?

[JohnEd]

Thanks Tom and Rick

Tom,

I didn't know that MCI was still using the "old" system in it's new coaches.  In fact, I thought I was seeing them set up like a Prevost.  I'll stand corrected.  Is it then true that the squirrel cage system is more efficient than the conventional bladed fan?

I think there is a problem "oversizing" the MCI rads.  Shape and availability and such.

Rick,

The D trucks all have a thermostat for coolant and still they have "blankets" on the front of the radiator to keep the engine warm.  I guess it is that cold airflow across the engine will cool it down in the cold winter months.  The shutters act like the blanket to stop air being blown across the engine after it has blown across the rad.  The thing that chokes off the air to the squirrel cage is redundant to the shutterstats but I suspect that its real purpose is to decrease the load presented by the squirrel cage when cooling isn't needed..  They run free if they can't get air to push.

John

[belfert]

MCI is still using the high mounted intercooler and radiator in the D series coaches.  I believe the E and J mount the two next to the engine, but not really sure.

[RickB]

John,

Another issue that becomes more noticeable in the winter is I removed the air actuated closable lower doors from my shrouds that work in conjunction with my shutters. I can't for the life of me remember the name (killed too many brain cells many years ago!) of that assembly but it closes off the air that the fans pull through the radiators and blow onto the motor. Being that I doubt I will drive my bus this winter any distance I just figured I would make it more of a "only use above freezing" rig.

I bet I'll get the itch halfway through winter though

All the best,

Rick

[rdbishop]

RickB,

Where would one get the gearbox rebuild kit and these speedy sleeves?

Richard

[RickB]

If my memory serves me, I got the kit from Mohawk and sleeves from C&J coach in Minneapolis. Phone nine five two 881-0034

I'll give you one bit of advice put the speedy sleeves in the oven at 350 for expansion. Brian Diehl reminded me of that AFTER I fought tooth and nail to get them on without heat.

I actually developed a small leak from the top housing gasket but other than throwing some oil for the first few minutes, the speedy sleeves and new seals have really worked out great.

[rdbishop]

Thanks RickB

Richard

[John316]

FWIW

Our D does have the two mounted up above the engine. Yes we do loose some space inside, but it has worked out okay. We haven't had any real overheating problems, and we have run a lot of the main passes in the west. We even ran local for a while, with the solenoids broken. We couldn't figure out why the bus was getting hotter then it should...I went back with my IR gun and was going to figure this out . I did the first step, and hit the test switch to turn the rad fan's on automatically. Nothing happened!?! Well I then look to where the air line was coming, and yes, when I took the bathroom out, I took that airline out, and capped it (it ran from the bathroom, back to the fans, and it was hidden). I fixed that, and no problems.

So I think the setup is pretty good. Keeps that old four stroke happy.

God bless,

John

[bevans6]

the dampers on the fan shrouds stall the air around the fan drums and really reduce the  power required to turn the fans.  they save a fair bit of fuel if you can run with them closed, even at warm-up only.  I'll be running a few hundred miles tomorrow in freezing temps, I'll be really interested to see if the shutters and dampers open at all!

Brian

[RickB]

Dampers!!! That's the word I was looking for...

Thanks Brian that would have kept me awake half of the night. That's good info on how and why they operate as well.

Learn something new everyday huh?

Rick

[buswarrior]

MCI E and J models have side mount radiator/aftercooler with the associated angle drive for the fan.
Combo belt and driveshaft angle drive configurations.

D model as noted rad/aftercooler above the engine, fans run by long belts off the crankshaft.

All have temp controlled clutches to turn the fans on/off.

For busnut retrofits, the transits often employ hydraulic fans instead of an angle drive. Makes the packaging easier, no pesky alignment issues.

Big pump and some big hoses run to a convenient location.

How about mounting the rad/aftercooler in the doorway of the last baggage bin?

happy coaching!
buswarrior

[buswarrior]

Without taking some measurements, don't be thinking there is much fuel economy advantage to the shutters or to a clutched fan in a coach while underway.

With no ram air, it isn't like a truck's fan, only coming on periodically. A coach fan, especially in a two stroke, will be running most, if not all the time, depending on the air temperature and load on the cooling system.

On a cool day, the shutters will close shortly after pulling off the road, you can be fooled, as they will close before you get parked and walk back there.

happy coaching!
buswarrior

[johns4104s]

RickB,

Were did you get your smaller pulley from? What was the cost? Are you sure that it does not do any damage ruining everything at a faster rate?

Thanks

John