| Author | Message | ||
| dougthebonifiedbusnut (24.218.119.24)
Rating: N/A |
crown guys especially but anyone else who might have some info i want to run up to four electric fans to replace my engine driven fan i have been told that electric fans are not sufficient to cool the 855 300 hp cummins i have to challenge the skeptics cause i have no truoble cooling it now as a matter of fact i have trouble getting it to running temp so i need to know who deals in big radiator fans thanks for any info | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
I'd think twice. I just finished a 1500 mile trip with my Crown- I now have a 2 speed fan clutch on my fan- and most of the drive went something like 75% @ low speed, 25% @ high speed, on about a 20 minute cycle. Remember that at "high speed" my fan is running as a normal fan would, and that's probably drawing about 20hp from the engine at that speed. "Low" is probably using about 4-5 hp. Now even 1hp worth of 12 volt fan is gonna draw roughly 80 amps, so it doesnt take long to figure out how much current 20 horsepower's worth will require on a long hill. Mucho!! When I first got my bus, the local big grade never saw the engine get above 140 degrees because as it turns out my thermostat was stuck wide opened...but now that the bus is done and there's some weight in it, it gets up to 190 on that same grade... | ||
| Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A |
Sorry Doug, but Gary may be right. Have you seen the size of the matched double belts that turn that fan on your Crown? They are huge! That fan must take at least 20 hp to turn at high engine speed. To have electric fans do the job would take soosss much energy (amps, watts, etc.) that it would overwhelm any known alternator. Oh, it could be done, but it would take the power of a dedicated gen set to do it. A big one. My 74 Crown 10-wheeler probably has the same setup you have. I am just going to leave the stock fan setup alone and just take the horsepower bullet it takes to run it. Crown went to a lot of trouble to engineer the cooling system and it works just great. Even in Bakersfield CA in August in over 110 degree heat. You said your mill is running cool/cold? Could be a stuck thermostat or the radiator shutters stuck open. My shutters stick open from time to time. Anyway, just my two cent's worth. Also make sure that do-hickie mudflap thing running across the bottom of the chassis is in good shape. Creates a low pressure area for the radiator. CROWNS FOREVER!!! | ||
| R.C.Bishop (128.123.88.7)
Rating: N/A |
Henry....I agree with you about the engineering that Crown did on their units. I doubt one could come up with a system for radiator cooling superior to ours. And for that matter, the same goes for most systems on the coach, as I am pretty sure RJ will attest. Interesting comment you made about the conveyor belt section that acts as a mud flap. I need a new one and you have prompted me to get on with it. Thanx, RCB | ||
| dougthebonifiedbusnut (24.218.119.24)
Rating: N/A |
ok guys heres my rationalization back in 83-86 i drove a trailerdump it had the very same engine that i have in my crown i grossed in the neighborhood of 110k to 130k lbs all day long and the engine always ran at 190where it is supposed to the reason mine takes so long to to get hot is because at around 28k lbs the engine isnt even breathin hard i think crown put all that stuff , the engine shroud, the big fan, the flap that im not convinced is to produce a low pressure area is because it takes a boatload of power to take the required amount of air and turn it 90degrees and also move it about 6 feed in the process ill bet you a buck that if you put 3 fans right in back of the radiator it will pull enough air to cool an 855 that aint working anyway this is of course in my humble opinion oh ya and just in case you need a little help i plan to incorperate a misting system but i dont think ill need it | ||
| RJ Long (Rjlong) (24.127.74.29)
Rating: N/A |
Doug - Where was the radiator on that trailer dump you drove? Up front, right? So when you were moving forward, you had the additional cooling help from the "ram air" effect, right? Now, where's the radiator air intake on your Crown? Behind the LF wheel, correct? What kind of "ram air" effect do you have with this location? Virtually none; matter of fact, if you open one of the windows right above the rad intake as you run down the highway, you'll see that there's practically no airflow thru the windows at that point - it's a relatively neutral pressure area. (If you open the window directly behind the driver's seat, you'll find it sucks air OUT of the bus - and that's only three feet or so in front of the rad intake!) OTOH, if you open the windows over the drive axle, or the next couple back, you'll see there's quite a bit of pressure blowing air INTO the coach. So, we have a situation where there is virtually no airflow at speed into the radiator, where the engine is working harder to punch it's way thru the atmosphere, and no benefit of ram air. How then, to keep the beast cool? I think a call to Gillig's Engineering Dept. in Hayward might be in order. Since their midship school buses used a similar set up as Crown, somebody there might have some the CFM specs for the radiator fans, or be able to look them up. Only when you have this info would you then be able to size the number of electric fans necessary to replace the single, SIMPLE, system the factory engineered. Oh, FWIW, GM also included a "mudflap" all the way across the engine bulkhead on their parlor coaches. This was to improve cooling at highway speeds by increasing the low pressure area under the powertrain. Hard to second-guess the factory, sometimes, altho many "mechanics" have removed them ". . .because it's not needed". . . Of course, then they wonder why the coach is having overheating problems. (Oh, wait. Maybe it's really a secret plot to get the coach back into the shop for more work???) So, if you want to replace the OEM design with one of your own, do your homework first. And I don't mean a WAG, either! HTH, RJ PD4106-2784 Fresno CA | ||
| Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A |
Years ago way back in 1970 or soossss I drove Crowns as a part time school bus driver while pretending to go to college in Bakersfield CA. My daily ride then was a nearly new 1963 Crown 10-wheeler with the 220hp 743 Cummins with a Spicer 5-speed. Average load was around 50 to 60 high school kids. One time both of the fan belts busted while on a run with kids. It was HOT (guessing September) but even with no fan the mill never got over 190. After checking for damage was able to finish the route and return to the bus barn without incident. The mechanic told me Crown over engineered the cooling system..... .....For the size and hp of engines they were running. He also told me (I think) that if all the windows were closed the mill will cool better. He also showed me the mudflap thing and how it worked. I do not know if your Crown would overheat or not running just electric fans instead of that huge factory fan with the huge two fan belts. Maybe you could try..... ....An experiment by taking off the belts and see if the mill overheats at all. This would be risky and may prove that the bus really needs the fan. Anyway, Crown did what they did and I would hate to be in a situation where electric fans simply could not keep up with the heat rejection requirements of the mill. This also concerns me because hopefully if the bank account holds out I want to upgrade my 250 hp non turbo 855 Cummins into at least a 400 hp with a turbo and intercooler. This is about as big as big as I can go and still keep the existing clutch and transmission (RTO-910) Any more power and the driveline would become suspect. I am concerned if the stock cooling system will handle the extra heat rejection---thus my decision to leave the stock fan and belts alone (nearly new condition) CROWNS FOREVER!!! | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
I just got back from driving my (cummins 220 non turbo) Crown on a nice long trip in the desert; most of the driving was 5000' or higher, it was 115 outside, going 65-70, and there were a LOT of times that the engine got up to 200 with the fan running full tilt. I had to gear down a bit and go slower to cool it off more than once. I don't think there's anything wrong with the engine, and the radiator just got replaced- it seems more like my .72 overdrive and foot- higher roofline probably upsets the overall cooling design a bit. So I have serious doubts at this point about electric fans in "serious" environments...I'm actually considering an aux. radiator, a radiator mist system, or both... Cheers! Gary Stadler | ||
| FAST FRED (63.215.231.180) Rating: N/A |
The easiest place to start is inside your engine. A really good 2 part antifreez flush with a bunch of full rinses could solve the problem. Green slyme gets built up inside the cooling passages if the coolant is not changed/ flushed often enough. A new radiator will not help an engine with 1/4 inch of crud buildup inside the engine. Then if you don't operate in the Real cold a mix of 30% real DD antifreez and 70% distilled water will still give the advantages of rust controll, anti cavitation ect, but will allow better heat transfer than a 50% mix. Might be worth a try ,along with a quick look for a soft hose, or a T stat thats not opening all the way. FAST FRED | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
Fred- I think it's real clean in there... according to the guy I bought the bus from, the engine was rebuilt about 2000 miles ago. I had to fix a valve cover gasket and when I took the cover off, it was so clean inside I couldn't believe it. I also changed the thermostat and everything inside the thermostat housing was clean as a whistle. I've flushed the system three times with both flush and water, and now running 50% of the red "extended life" antifreeze/ distilled water. Years ago I had a Superior gas pusher that ran cool as a cucumber, but the cooling system design was so close to the edge that when I removed the 4 interior heaters the engine overheated. A bigger radiator fixed it instantly. Like I said, I'm guessing that the Crown design was close too, and my additions and modifications to the bus have simply pushed it over the edge for the radiator sizing. At sea level or at night in altitudes it has no problem at all... Cheers Gary | ||
| dougthebonifiedbusnut (24.218.119.24)
Rating: N/A |
hey rj you raise some good points the most troubling is the fact that at speed its going to be hard to get air directed thrue the rad that big noisey fan does that thanks for the gillig info im going to talk to them BTW what the heck does WAG mean | ||
| dougthebonifiedbusnut (24.218.119.24)
Rating: N/A |
hey gary in the biggining i thought i would route the air going thru the heaters one in the back and one in the front somehow out of the coach aiding in the cooling but iv never had a colling problem what you said reminded me of that did you happen to see the lady ridding the unicycle while playing the fiddle at burning man | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
Doug, I didn't see the lady you're talking about at Burning Man but what I did see more than made up for it! I'll post a few pics as soon as I get them developed. (ya NEVER take an electronic camera out there if you value it's life at all...$5 throwaway film cameras work great!!!) So how do I now feel about having stuck 150 gallons of water storage and dump-space on my bus? Perfect! In the week we were there in the desert, both my wife and I took a few "gallon" showers and one "luxurious" shower each. We also let four friends take showers that were unattended... Plus all the cooking, cleaning, etc. We went thru about 110 gallons of water in total, and so I feel there was a perfect margin left. Hee hee, one of our friends went in and rented a 35' motorhome with another couple, and the first night there the gal from the other couple got mad at a frypan she couldn't get clean, and she went thru the entire RV's tank of water trying to clean it. I guess she's kinda dumb...anyway they all went without "utility" water for the whole week...no showers, no dishes, and had to use the portapotties provided by the event (YUCK). Makes me feel fairly happy that I put individual valves in my three 50 gallon tanks so no one can ever do that to me!!! | ||
| RJ Long (Rjlong) (24.127.74.29)
Rating: N/A |
Doug - If you think the OEM fan is noisy, what kind of sound do you think five or six electric fans are going to make? Easiest way to get rid of engine fan noise on a Crown or Gillig mid-ship is to close your window - yes, the one right there by your left shoulder! And to really quiet it down, besides closing the window, turn on the aux driver's fan(s) hanging from the center windshield header. . . Or get a pusher chassis. . . (JK) WAG = Wild A** Guess RJ PD4106-2784 Fresno CA | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
Whoops... In my haste in changing out my old leaky radiator to a newer one (from the Crown Junkyard of course), trying to get it done in time for the trip (took me from 6am to 12 midnight) and because the newer one had different mounting schemes and the fit was somewhat of a hassle, I didn't put the two sheetmetal radiator sideplates back on before the trip, figuring they weren't "really" necessary. Hee hee, as it turns out, starting the engine and feeling around today, there's probably 20% of the hot air coming out of the fan- hitting the frame, engine, etc, turning right back around and being shot straight toward the front of the bus along the interior of the bus's sidewall, and going right back into the radiator with that rear sideplate missing. Guess tomorrows' desert trip will tell, but now the side-plates are back on I bet I won't see the engine get a drop over 180 from now on...  duh... Gary | ||
| RJ Long (Rjlong) (24.127.74.29)
Rating: N/A |
Gary - Hmmmmmmm. . . sometimes it's hard to second-guess the factory, eh?? 8^) RJ PD4106-2784 Fresno CA | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
Hee hee! Yup! (although...I'll bet they did a lot of the designing the same way I did, by accident...) Gary | ||
| Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
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Actually I would bet that these long gone Crown Coach engineer guys just sat around dreaming up new and expensive ways to make the Crown Super Coach better than it already was. CROWNS FOREVER!!! |