Radiator Mister

[RJ]

Gary -

Not condemming anyone, just pointing out simple things.  Butnuts are some of the most creative folk I've ever run into when it comes to solving problems, or should I say, overcoming various challenges - chassis & house both.

FYI, All of the coaches I drove over those years were stock, often fully loaded w/ passengers & luggage.  MCIs are the most notorious for overheating stock cooling systems in our hot SW deserts, stuff a "monster motor" in the tail w/o any other changes and it was a recipe for disaster.  And some charter bus operators tried just that - I even had to go out a couple of times to rescue their passengers.  Not a pretty sight when you've got 40 people stranded by the side of the road in the middle of the Mojave Desert.  The company I worked for had a strict policy that if you overheated and shut down due to driver negligence, you were headed to the unemployment office.  You learn quickly under those circumstances!

I think you'll agree that if you stuff a 454 big-block in a Chevette, you're going to have problems w/o a lot of modifications.  Extreme example, but you get the idea.  Even Geoff, whom I have tremendous respect for, admits that adding the additional load of his trailer/toad to his coach taxes the stock cooling system.  So solutions have to be sought, as has been done.

With the two-stroke Detroits, the sweet spot for pulling grades seems to be in the 1700 - 1900 rpm range on a partial throttle.  Running it on the governor with black smoke pouring out the tailpipe is guaranteed to overheat the beast.  The Series 60 has a sweet spot that's several hundred rpm lower - TomC probably knows the range and can chime in with the numbers.  The key?  "Partial throttle!"

I guess my major point is this:  Most busnuts overheat their coaches because they're pushing too hard for the conditions and not paying attention.  Otherwise known as my tongue-in-cheek comment about excessive weight in your right shoe.

Perhaps the above helps explain why I often talk about Aesop's Fable of the Tortoise and the Hare.  Buses are not hares, yet owners often try to drive them that way.  Those who do end up with various problems, asking for solutions.  Those who drive their coaches like a Tortoise, arrive unstressed, happy and ready to roll again next time.

FWIW & HTH. . .

[TomC]

Yes the Series 60 sweet spot is lower in the rpm band.  Even though the maximum torque on a Series 60 is at 1200rpm, you want to be a bit higher around 1400 when pulling with a bit of pedal off the floor (I'm talking a 6% grade of more then 5 miles like the Grapevine, or west bound coming into Butte, MT).

On my 8V-71, I like running it in 1st gear with the torque converter locked up at 2100rpm for maximum coolant and fan action.  At 2100rpm, I'm at about 36mph-which is about the same speed as big rigs will pull a 6% grade at.  Good Luck, TomC

[wg4t50]

Gee,the MCI7 barely has enough coolihg for a 8V-71 on a cool day, why I took all the  stock stuff out, both radiators, gear box fan assy, and installed a 4' X 6' stationary radiator that had recored with a girdle to keep the tubes inplace.
This was done for the 12V-71 setup, worked OK, until I did the twin turbo setup, that is when I found the home made mister system so beautiful for mountain games.
Best toy I ever had.
Dave

[edvanland]

geoff put a mister on my MCI7, 8v92 auto, like he put on his when he rebuilt our engine. It works great now we can go up hills pulling our trailer without it over heating. I also go slow and keep the RPMs up. Dont care how fast I go up the hill as long as I go and do not overheat. Yes I had new radiators put in all leaks sealed and also a aux radiator built which is 24 inches wide 36 inches tall and two inches thick, it helped but the misters Geoff put it worked.
I live in central AZ across the mountain from Geoff so no matter where we go we have to climb long grades.

[Scott & Heather]

Just a quick side thought. It was mentioned to use reverse osmosis or distilled water for your mister system. Has anyone looked into the effects of this long term on aluminum radiator fins? RO or distilled water can at times be high acidity. So much so that I read an article that discussed ways to protect metal pipe against RO water corrosion in third world countries where water purification systems are being set up by troops. Just a thought. I personally want to install a mister and I have an on board RO system currently. Just want to be sure I'm not eating away at my fins. Something about removing all minerals from the water raises acidity and lowers pH.