Bus Conversions dot Com Bulletin Board
August 22, 2014, 08:40:47 PM *
Welcome, Guest. Please login or register.

Login with username, password and session length
News: If you had an E-Mag Subscription: It will not be stolen by your mailman or your neighbor who also may be into buses.
   Home   Help Forum Rules Search Calendar Login Register BCM Home Page Contact BCM  
Pages: [1]   Go Down
  Print  
Author Topic: heat records in the southwest, radiator cooling  (Read 875 times)
lvmci
Hero Member
*****
Offline Offline

Posts: 637





Ignore
« on: June 29, 2013, 09:59:36 PM »

Hi All, working down in LA again, driving bus from Lancaster/Palmdale to San Berdo, then on to Van Nuys, very hot here in the High Desert, the Italian Greyhound is running hotter than usual,

I think that's around 190 degrees, down shifted to drive it like your mad at her, did not cool her down, over 115 degrees outside. This brings me to my question posed to all you Gurus. That saying, drive her like hour mad at her, told to me by the great old mechanic at ww williams who first introduced me to the 8V71, I think means keep the rpms up, running the engine at a higher rpm keeps the the fan belt turning the squrill cage turning faster sucking more air thru the radiators, as one of the functions, keeps the engine from overheating, I know there is power band and other issues, but about cooling, am I coming away with the right idea, higher rpm equals cooler engine, because the fans are pulling more air? I have been thinking about electric fans, a la fans for airconditioner radiators, is it the condenser outside? Why not eliminate the squarl cage fan belt to run it and replace it with electric fans on both side of the MCI5A and cool more effeciently, am I wrong,  please correct me if so, she normally runs at 180 degres,lvmci...
« Last Edit: June 29, 2013, 10:05:11 PM by lvmci » Logged

MCI5A 8V71 Allison MT643
TomC
Hero Member
*****
Offline Offline

Posts: 6721





Ignore
« Reply #1 on: June 29, 2013, 10:05:26 PM »

There is NO electric fan that can move as much air as the squirrel cage blower in your bus. If and when your bus starts over heating, pull over and let it fast idle to cool down, then proceed. When the weather gets over 90 degrees, I usually have to use my misters (I have the biggest radiator and 8 blade continuous run fan). Good Luck, TomC
Logged

Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
lvmci
Hero Member
*****
Offline Offline

Posts: 637





Ignore
« Reply #2 on: June 29, 2013, 10:10:04 PM »

Hi Tom, is 190 degrees overheating? Or something hotter, she was stabile at that higher temp pic, lvmci...
Logged

MCI5A 8V71 Allison MT643
TomC
Hero Member
*****
Offline Offline

Posts: 6721





Ignore
« Reply #3 on: June 29, 2013, 10:15:48 PM »

190 is not over heating. That second notch on your temp gauge is usually the half way point between 180 and 250 which is 215. I would never go above that. My alarm comes on at 220, and have only had that happen once. Good luck, TomC
Logged

Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
Scott Crosby
Full Member
***
Online Online

Posts: 109


WWW

Ignore
« Reply #4 on: June 30, 2013, 03:47:12 AM »

I changed from that style gauge to a digital readout. It's much more accurate than trying to play a temperature guessing game on a 1/4" of dial movement. 
Logged

61 GM Fishbowl 4516 102" 35'
Ed Hackenbruch
Hero Member
*****
Offline Offline

Posts: 2381




Ignore
« Reply #5 on: June 30, 2013, 07:34:49 AM »

 Ever hear of the law of diminishing returns?   Seems like long ago i read that on the 5 series that at 1700 rpm is where you got maximum cooling from your fans.....lower than that and you are not turning them fast enough and are also getting close to engine lugging range which will build heat. Running at max rpm will not increase your airflow although it seems like it should, (it might some,) however any increase in airflow will be more than offset by the increase in heat from the higher rpm of the engine.  Example; if you are at 1600 rpm you are using a certain amount of fuel and generating a certain amount of heat. If you run it at 2000 rpm, (an increase of 25%) you are using about 25% more fuel and generating 25% more heat during the same time. This heat is going to be harder to get rid of and will tend to build up some over time. Try running at a little lower rpm and see if your temps stay a little lower. 
Logged

1968 MCI 5A with 8V71 and Allison MT644 transmission.  Western USA
wg4t50
Hero Member
*****
Offline Offline

Posts: 765





Ignore
« Reply #6 on: June 30, 2013, 08:33:10 AM »

A proper mister does wonders, using my home brew misters was able o keep foot on floor (throttle) with both 12V-71 & 8V-92 on mountain when 100f, never went over 205f at the very worst  point.
Used about 1.5 quart of windshield washer fluid per  3-4 mile hard pull,  as said, was a hone made mister, never saw any other.
Dave M
Logged

MCI7 20+ Yrs
Foretravel w/ISM500
WG4T CW for over 50 wpm for ever.
Central Virginia
Ace
Hero Member
*****
Offline Offline

Posts: 1157





Ignore
« Reply #7 on: June 30, 2013, 08:17:59 PM »

I've been fighting what I call overheating (high 190-205's) on flat ground in Florida on a hot day, with my 8v92 but after Installing what some bus nuts referred to as an oem supplied air/rock deflector, sealing up around the perimeter of my NEW radiator, installing an electric fan, mounted on rear engine door louvers and still running hotter than usual temps, I think (Huh) I cured my problem! A while back I removed the original oem bathroom black tank which left an opening approximately 2x3 feet in the engine compartment. I do t exactly know why but after reinstalling this tank with the top cut out to make it a storage box, the temps never went above 191 on flat ground on a very hot day and Before I couldn't run faster than 60-65 before temps went up but after reinstalling this box/tank I found I could run 75 plus and never go above 191 until I started climbing a grade where the temps rose to just 195 but soon went back to the 191 range when leveling out! I think it must have had something to do with how the engine compartment hot air was escaping. Somehow this open hole was causing the heat to stay and not flow outward.
I too made a myster but never needed it OR the electric fan which I only use after parked and engine shut down. It helps to remove the radiant heat from engine and not heat up the BR above engine!
So far, so good!


Sent from my iPhone using Tapatalk
Logged

Ace Rossi
Lakeland, Fl. 33810
Prevost H3-40
lvmci
Hero Member
*****
Offline Offline

Posts: 637





Ignore
« Reply #8 on: June 30, 2013, 08:27:18 PM »

Hi All, traveling from Palmdale/Lancaster thru Victorville to get to I15 and down the Cajon pass, I purposely did not use the misters to see how hot it would get on a realitively flat California, area, lvmci...
Logged

MCI5A 8V71 Allison MT643
luvrbus
Hero Member
*****
Offline Offline

Posts: 12235




Ignore
« Reply #9 on: June 30, 2013, 08:41:22 PM »

Depends on which water pump your Detroit has they will move 58 to 93 GPM of water @1500 rpm enough radiator,fan for air movement they will cool
« Last Edit: June 30, 2013, 08:43:18 PM by luvrbus » Logged

Life is short drink the good wine first
niles500
Niles500
Hero Member
*****
Offline Offline

Posts: 1188


ROSIE




Ignore
« Reply #10 on: June 30, 2013, 10:45:41 PM »

Thankfully this didn't become an ELECTRIC FAN thread  Grin
Logged

(\__/)
(='.'=)
(")_(")  

- Niles
TomC
Hero Member
*****
Offline Offline

Posts: 6721





Ignore
« Reply #11 on: July 01, 2013, 07:22:33 AM »

My initial misters were a 15 mister kit I bought from Home Depot. While it mildly worked, was not satisfied with it's results. What really worked is I drilled out two of the nozzles with a 1/16" drill bit. Now it flows some water. I have my misters hooked into my water system with an electric water solenoid. Good Luck, TomC
Logged

Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.18 | SMF © 2013, Simple Machines Valid XHTML 1.0! Valid CSS!