| Author | Message | ||
| Kevin Hatch
Rating: N/A |
I know this subject was touched on a lot in a prevoius thread about up hill shifting, but I never really saw an answer to my question. My 8V71 runs about 185 normally on the gauge. Is is safe all the way up to the red zone on the gauge? When on a trip up to Denver a couple weeks ago it got a little warmer on the climb, maybe 190-195 or so, keeping the revs up and monitering for black smoke. I also moved the bus to my storage place yesterday (about 35 mi away) and it was about 105* here yesterday. It got up to about the same temp, maybe a bit hotter, with a pretty stiff head/cross wind running 70ish. Do you guys think I'm ok temp wise? | ||
| Gary Carter Rating: N/A |
The rule from DD is do not make vapor. This means at sea level and a 50:50 mixture the boiling point of you coolant is over 230 degrees. Do not remember the exact temp. If you have a pressure cap and carry 10 lbs. of pressure the boiling point is over 250 degrees. As you go up in altitude the boiling point decreases, so just as you need it you loose it. The boiling point of water at 5000 feet is below 190 degrees I believe. So in summary don't make vapor. | ||
| Bob Wies (Ncbob)
Rating: N/A |
Might I ask what might be construed as a "stupid question"? It has come up before and I thought I'd throw it out there..... What % of water/anti-freeze are you running in your cooling system? A 50%/50% mixture of the above will protect your cooling system to -35 degrees. I've found that 'some people' when topping off their systems add 100% anti-freeze. Ethelyne Glycol does NOT have the best cooling properties in a greater than 50/50 mix. FWIW NCbob | ||
| Frank Allen (Frank66)
Rating: N/A |
strt to get excited over 200, i shut down at 205 , a climb will do it for you. 195 should be just fine Frank allen 4106 | ||
| Kevin Hatch
Rating: N/A |
I'm pretty sure it's real close to 50/50 mix. I had the engine swapped real recently, so it's fresh too. What temp do some of you run at on 100+* days with a head wind? Just want to be prepared as the band and I prepare for the summer touring season! Cheers! Kevin Hatch 1970 PD-4905 | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
Both my Crown and Bluebird run at 180, and going up nasty grades on 110 degree days gets them up to 195. If I ever hit 200 I slow/gear down. The old Cummins engines have warnings in their manuals never to exceed 200... for me at least that's a good number for any of my diesels... | ||
| FAST FRED Rating: N/A |
For corrosion protection only 35% neeed be antifreez, the rest distilled water. Antifreez only has 5/8 the heat transfer ability of water , so the MORE water the better cooling. 200F on the gage will usually be enough for steam pockets to begin to form in the head passages, time to shut down or back WAY off! FAST FRED | ||
| herman Rating: N/A |
www.evanscooling.com | ||
| Jarlaxle Rating: N/A |
Yes--Evans NPG is incredible. | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
Anyone have firsthand experience with the stuff? Reading the website it is one of those things that sounds too good to be true, or maybe too expensive to play with... but I'd be real interested in hearing from anyone who's using it. Might make that whole thread on misters obsolete!!!  | ||
| herman Rating: N/A |
Well, here's a guy that sells it along with all kinds of pickup-class diesel hopup stuff; from my experience he'll talk straight: www.dieselsite.com Gary, I'm pretty sure that this guy is on solid ground. My big concern is that this stuff might be a more or less ordinary chemical vs. some special blend / secret sauce, and that if I knew where to get it without the fancy label on it that I could pay a lot less. For sure it ain't pills for your gas.... This guy Evans has done some interesting stuff (on 'Vettes, I think), like reversing the flow through the engine so that the heads get coolant first from the radiator and then the flow is down into the block; keeps the engine overall at a more even temperature. He also rebuilds water pumps with different impellers (instead of cheesy OEM stamped metal vanes) to pump more efficiently, and to work better with the fluid; don't recall the details. A note on FF's comment about how glycols have a lower specific heat than water: This is true, but what it in practice means in a closed system such as an engine's is simply that, for a given amount of thermal energy that the engine is generating and the cooling system is disposing of, the delta T between the hot and cold sides of the loop is larger. As long as there's enough clearance between components, the components themselves can take the heat, and the oil film doesn't go south, higher temperatures are fine; improves the basic Carnot cycle thermodynamic efficiency. One trouble may be that some engine computers will start defueling when they see high temps, assuming that yesterday's tech is still being used. | ||
| FAST FRED Rating: N/A |
" but what it in practice means in a closed system such as an engine's is simply that, for a given amount of thermal energy that the engine is generating and the cooling system is disposing of, the delta T between the hot and cold sides of the loop is larger" This is true in autos and other vehicles with PRESSURIZED coolant systems , but most of the old busses only have a 2lb or so systen pressure . So basically the coolant still boils at 212F , and 200 is still the time to back WAY off. . FAST FRED | ||
| Marc Bourget Rating: N/A |
Got a call back from a tech person from Evans respecting my 8V92. They do "kit" DD 2 strokes with great success. Need to alter the overtemp shut offs to allow for greater range/variation. The higher temps are "allowable" as the engine coolant "interface" where the heat is exchanged is fine despite the higher temps. | ||
| Stan Rating: N/A |
At standard temperature and pressure a 50% solution of ethylene glycol and distilled water will boil at 228.2*F. A 2# pressure cap will only raise the boiling point by about 6*F. A 10# pressure cap would raise the boiling point by about 30*F. The purpose of a 2# cap is primarily to stop the reduction of the boiling point with increased altitude rather than to increase it at sea level. At 10000 feet water boils at about 190*F. None of this has anything to do with red zones or cracked heads or NPG coolant, just some numbers to keep in mind when you are looking nervously at your temperature gauge. | ||
| Brian Brown (Blue_velvet)
Rating: N/A |
RE: the Evans stuff, it looks a little $pendy to replace the 90 quarts or so. BUT, I guess it's a lifetime fluid (no more coolant changes). They recommend zero pressure, which is great for the busses that have so little pressure anyways. I'd suspect that thermostats would need to be replaced also?? bb | ||
| Jarlaxle Rating: N/A |
Evans boils at, IIRC, about 290 degrees (and gets "a little slushy" around -40). They suggest a low-pressure (3-5psi) cap. It's not cheap, but it really works. I run it in my Fummins, & my wife runs it in her Grand National. Also, the reverse-flow cooling was done by GM from the factory on L99's, LT1's & LT4's--my 95 Caprice has that system. | ||
| herman Rating: N/A |
Apparantly, GM stole the technology from Evans; automobile OEMs have something of a reputation for that kind of stuff. See: http://www.evanscooling.com/main25.htm for materials properties; the stuff boils at more like 370F - hot enough for you? | ||
| truthhunter@shaw.ca Rating: N/A |
This evanscooling stuff might be a good coolant for co-generation heat recovery from the exhaust waste heat of a generator for interior heating with a boiling point of 375 F. | ||
| truthhunter@shaw.ca Rating: N/A |
If I understand there literature correctly , using this Evans propylene glycol as engine coolant: I am not sure you will get the same cooling ability. It list the specific heat of Evans (propylene glycol) as .68 , ethyl glycol at .82 and water at 1.0 , does this not mean it has the least ability to remove heat and therefor you would get less removal of BTU than regular coolant; with strait distilled water as the best at heat transfer (before rapid corrosion creates the insulating effect in your water jacket). Isn't this why they suggest there radiator replacements and the water pump replacements? As these modifications are needed to handle the fact that this stuff is as thick as syrup and not as effective at transferring heat away from the engine. Not that they come right out and say this in plain simple laymen's English during their efforts to make one think need to buy the product as it is some much better that anyting else. I am also a little confuse with the claim of the product not causing corrosion yet only good for ten years or 100,000 miles . Later I get even more confused as I read that there is a new formula called NPG PLUS that has new corrosion inhibitors added and don't understand why you would need inhibitors if it does not cause corrosion? I did understand the attempt to get a slight improvement on the heat transfer ability with the new improved Plus formula with a slight increased of specific heat value of .06. So did I misunderstand the scattered facts on this Evans coolant or is it actually a less effective coolant than standard ethylene glycol for 6 times the price (not including modifications recommended)with the only possible advantage being that it has a (relatively irrelevant in a Jimmy 2 stroke Diesel that is destroyed at 205 F) much higher boiling point than 50/50 ethyl glycol and perhaps slightly less corrosive than expired ethyl glycol for extended use of up to ten years but only 100,000 miles between flushes/inhibitor restoration and not considered highly toxic at this time? Confused consumer minds wish to know if the facts ! | ||
| herman Rating: N/A |
TH, Puhleaze, easy on the cynism, dude! See my above comments about FF's comment about specific heat. A lower specific heat doesn't mean that it can't transfer as much heat, it means that in doing so the coolant will experience a higher delta T. A lot of the folks to whom they sell are racers, ergo the emphasis on optimized water pumps and radiators. Similarly, the NPG exists to conform with certain racing rules that disallow coolants containing ethylene glycol. Absent such a rule, the + version is a better product. Why is this so hard to understand? Why is this justification for jaundice? " ...or is it actually a less effective coolant than standard ethylene glycol for 6 times the price... " Umm, define "effective". Kinda depends on one's values - in my view, using a coolant with a boiling point so low that the thermodynamics of combustion have to be compromised is hardly what I'd call "effective". You're just biased by your history, which has defined your default. As for the higher cost, well, quite possibly, were it the default coolant for all these decades, perhaps it wouldn't cost so much. I will say that their style of web site, where there is substantial replication of content in multiple areas that target different audiences / market segments, is not my favorite, as it is difficult to keep unified, and one ends up searching myriad nooks and crannies seeking all the details. Confused consumer minds occur because they are ignorant of critical thinking skills, and unpracticed in examination of internal presumptions and biases that have become adopted on mere basis of repeated exposure rather than intrinsic merit. | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
Kinda looks like they started with NPG and later came up with NPG+... to reiterate what they say about it, "NPG+ is new coolant providing dramatic improvements in heat transfer and viscosity that make the new fluid a "pour-in," not requiring changes to cooling system components." ...and "NPG+ retains all of the benefits of Evans original NPG coolant, while improving upon its thermal conductivity by about 32 percent and reducing its viscosity by about 65 percent." Ok so far so good, the stuff apparently isn't as thick as the old NPG. In fact I searched the usenet and found this tidbit posted by a guy named Marty Bose: "My context is a bit different than most in this newgroup; I own an RV, but I also own a 1947 Plymouth, which uses a non-pressurized cooling system, and which currently has a hotrodded flathead 6 in it. I used to have a lot of trouble with boiling the coolant out when driving around in the summer. Switched to NPG+, no problems since! This is not to say there weren't a few initial issues. This stuff is a very thin viscosity, and will find any place in the cooling system to leak from. Had to spend a while tightening up hose connections (and sealing a couple of headbolts) before it stopped weeping." Hmmm... looks like you can just pour it in and go... It's sure sounding good.... I may have to call them and ask a lot of questions.... G | ||
| Marc Bourget Rating: N/A |
Gosh, Herman, I wish I had your way with words! (no, I'm not being sarcastic, but appreciative) "using a coolant with a boiling point so low that the thermodynamics of combustion have to be compromised is hardly what I'd call "effective". The apparent weight of opinion earlier was that all cooling ills could be cured by the use of misters. I almost felt I was a voice wandering in the desert. It's nice to see someone focus on the cardinal issue of cooling - maintaining optimum thermodynamics, short of damaging performance or equipment. | ||
| FAST FRED Rating: N/A |
"maintaining optimum thermodynamics, short of damaging performance or equipment." Great concept but, to do it you need to (mostly) follow the installed antifreez mfg recomendations Usually to drain & flush with a chemical cleaner every 3 years or so. Want to take a Poll on how many bus campers get this PM? I only know of 1, mine. FAST FRED | ||
| R.C.Bishop
Rating: N/A |
FF......count me in,too (two). Last done this past fall. RCB | ||
| Buswarrior (Buswarrior)
Rating: N/A |
FF, Count me in for best intentions. Bought it and have the DD cleaner on the shelf, just have to get 'er done! happy coaching! buswarrior | ||
| herman Rating: N/A |
And, why need we periodically remove corrosion from our cooling systems? Could it be the use of a an inferior (read: corrosive) substance as a coolant, i.e. water? I swear, you could lay a gold ingot at the feet of some folks and they'd take issue with it or think it was some kinda doorstop..... | ||
| Buswarrior (Buswarrior)
Rating: N/A |
I use green goo in the rads because I am less than rich. Also the reason why I have a busconversion. But I like to learn! When those lottery numbers come up, I'll know what to do then! happy coaching! buswarrior | ||
| Brian Brown (Blue_velvet)
Rating: N/A |
When using "green goo", just make sure it's DD-approved stuff, and NOT automotive-grade coolant. Chromates and other additives are not good for the DD's, and they need different inhibitors. Just an FYI, bb | ||
| FAST FRED Rating: N/A |
"And, why need we periodically remove corrosion from our cooling systems?" You're NOT removing corrosion. When cleaning and flushing your cooling system you're getting rid of the chemicals that were installed in the antifreez on puropse to prevent the cylinder walls from thinning from cavitation. When the diesel cylinder fires the culinders actually expand (that diesel knock) and contract. As they contract the pressure of the coolant is lowered enough to cause air bubbles by cavitation. This cavitation EATS the outside of the cylinder wall, untill the wall is thin enough to leak. The antifreez folks use a chemical that forms a thin protective barrier , by its presence. The barrier can NOT stop the cylinder wall ringing , and the cavitation , it just gives the air bubbles a replacing surface to eat. Unfortunatly the chemicals that give the cavitation protection clog up the REST of the engine and radiators by growing ever thicker . Hence the antifreez guy caution to CLEAN the system periodically. FAST FRED | ||
| herman Rating: N/A |
OK, fine, so the point of cleaning is for the SCA, which in turn is to counter a nasty property of the water... sonoluminescence, or even sonofusion, anyone? Really, it makes no difference. Get rid of the water, then begone not only corrosion but also the need for the SCA, and with these any need for periodic cleaning. | ||
| Buswarrior (Buswarrior)
Rating: N/A |
Thanks Brian, I should have said: "the proper green goo" happy coaching! buswarrior | ||
| Stan Rating: N/A |
Since I can't read, I just had to do what Joe (my idiot neighbor) told me what was best. I started out with methyl hydrate and electric frost shields because you had to run the engine so cold you couldn't defrost the windshield. Somewhere around the end of WWII I went to "Prestone Permanent Antifreeze". It got changed when a leak dumped it on the ground. With more modern vehicles, dealers installed flushing machines and looked after the cars and pickups. Big vehicles got drained and dumped into the sewer (so the dogs couldn't get into it) and nobody had heard the term "Toxic Waste". In those sixty years, I never had a problem with a cooling system that the local radiator shop couldn't fix at low cost. I drove on lots of gravel roads and had lots of stone puntures in radiators and added lots of sealing oompounds to get me home. Do you suppose that our engineering has gone backwards? I know that engines run hotter and radiators are made lighter so that we can get the fuel mileage back to where it was before the EPA got involved. I just donated my 1950 Studebaker to a museum. It went 30 miles to the Imperial gallon of gas but would have been better if I had bought one with an overdrive transmission. I expect most of you remember the early seventy cars that gave ten miles to the gallon. The manufacturer and EPA convinced the public that it was better for the environment to burn twice as much fuel as long as you put the exhaust through a muffler filled with platinum. What has all this got to do with "How hot is too hot". The simple answer is when the engine seizes, it is too hot. | ||
| johnwood
Rating: N/A |
Hey Fred; I have a question....... do all diesels cavitate on the cyl walls, or just sleeved engines? I have a cast iron 3208T and have been running auto glycol in it 'cuz I heard that only sleeved engines have an erosion problem. And....... I figured that the plain EG stuff would not gum up as quick....... tho I still shange it every 3 yrs. jw | ||
| FAST FRED Rating: N/A |
All engines will cavitate the cylinder walls with each heavy power stroke. IF the cylinder wall is incased in a sleeve the cooling is poorer from the extra thickness for the heat to go thru . The newest diesels simply have the cylinder wall it self exposed to the coolant , better cooling , but more risk of pin holes with the thin cylinder wall exposed to the cavitation. Da Book for my 4106 8v71 talks about draining the water for overnight freezing situations , and simply refilling with plain water. That was a long time ago ,and for commercial service, OUR goal is to "stop the clock". FAST FRED | ||
| herman Rating: N/A |
" do all diesels cavitate on the cyl walls... " and " All engines will cavitate the cylinder walls with each heavy power stroke. " I don't believe that's true. Cavitation is what some liquids do when exposed to rapid decreases in pressues, e.g. when adjacent to vibrating metal, e.g. cylinder walls, propellers, pump inlets, etc. It can be caused by either dissolved / entrained gasses in the liquid, and/or by temporary phase changes, i.e. localized momentary boiling of the liquid due to the pressure drop. This action (specifically, I believe, the pressure spikes that occur when the bubbles collapse) can corrode nearby metals, and the resultant pits can, in a vicious circle, serve as nucleation sites and exacerbate the liquid's tendency to cavitate. This corrosion is referred to as cavitation damage / pitting / etc., but it is not itself cavitation; again, that is a behavior of a liquid. | ||
| Marc Bourget Rating: N/A |
Herman, I believe it is true, probably for effects that you didn't take into consideration. A metal/coolant interface can promote bubble formation. Proper consideration of your point requires reference to the "partial pressure" phenomena of the particular liquid. Not only does the cylinder wall "move away" suddenly, the partial pressure of, for instance water, (a measure of its "desire" to boil), contributes to bubble formation. Significant, since a pressurized cooling system purposefully maintains the coolant at a temperature close to boiling. Surface tension and inter-molecular forces, (hydrogen bonding and other physical chemistry factors) can, at the same time, both promote bubble formation and increase the energy released in their collapse. (Think of a baloon made of thicker rubber). Interestingly, articles on cavitation explain that the high energy involved in collapsing a bubble and the incompressibility of a liquid, can lead to "rebound formation" of another cavitation bubble. Like Carl Sagan's "billions and billions of . ." comment, this makes lots of tiny "hammers" wearing away at the cylinder walls. WW, (more accurately, dish soap with red dye sold for a very high price), reduces surface tension and interrupts the contribution of surface tension to the energy "encapsulated" in cavitation bubble formation (a "turbo" for bubbles) and released in it the bubble's collapse. WW also helps to increase water to metal "contact time" giving the cooling improvement witnessed by others to this BB. IMHO, it's not so much the "pressure spikes" you referred to but the mass (of the coolant) moved by those spikes, in conjunction with mineral deposits (like tiny grains of sand) that abrasively errodes the cylinder walls. By this comment I'm not saying you're wrong, just trying to be a tad more accurate in the actual dynamics of the phenomena. | ||
| johnwood
Rating: N/A |
Cavitation is a real danger. This I know from working with hydronic pumps. Even the little wet rotor circ pumps have been known to explode rather violently from the effects of cavitation. BIG pumps do it quickly and rather spectacularly. Mfg specs state NPSH (a net positive inlet pressure for proper operation) and this is the reason. I guess the info I am looking for is this; will the effects of cavitation hurt my cast iron block. Does it occur in a stiff cast cyl wall as opposed to a thin wet sleeved engine? | ||
| Marc Bourget Rating: N/A |
Cavitation is a fact of life. Having walls thick enough to reduce or eliminate the vibration that leads to cavitation would prohibit proper heat transfer for cooling or you'd have to slow the engine down so much performance would be killed. You can reduce its effects by using distilled water (no or less abrasive). Use a cooling system cleaner, advocaed by FF, Utilize WW or its equivalent. Add/ replace your Cooling system filter. | ||
| herman Rating: N/A |
Cavitation damage is not cavitation itself - I assert this unequivicably. http://en.wikipedia.org/wiki/Cavitation Helluva resource, that site. And, no, I didn't write the article... And, at the risk of being accused of beating on horses, note that Evans' products have very low vapor (i.e. partial) pressures, so cavitation is negligable, therefore no need for SCA, nor the periodic cleaning of the cooling system that it in turn necessitates. | ||
| Gary Carter Rating: N/A |
Cast iron block suffer from cavitation just like wet sleeves. If you doubt this just ask Ford power stoke owners with pourous blocks. For years Ford said it would not happen and used no wetting agents. They have since learned about diesel engines. Cummins in the B engines uses a water filter that contains a wetting agent. And for the record the 3208 block is subject to cavitation is the cooling system is not maintained properly. | ||
| David Dulmage (Daved)
Posted From: 142.46.199.30 Rating: N/A |
I had my antifreeeze changed two years ago. I found it was down about 8 quarts at the beginning of this season. I haven't found any obvious sign of leakage, either internal or external. The oil is clean, the engine runs fine and doesn't smoke, but it did overheat climbing a long grade at night. I was probably pushing it harder than I should have and the traffic light at the top of the grade was red when I got there Starting off from the intersection the gauge climbed to about just over 200 degrees and the engine shut down, but almost immediately cooled down to about 195 and restarted. It ran fine at about 185 the rest of the way to my destination, but when I was parking it (about a 10 minute operation in the dark), backing into a tight campsite, it shut down again, but cooled down right away. I added the aforementioned antifreeze and deionized water (50/50 mix) and tried running at fast idle to see if it would heat up. It was fine, but of course that's not the same as running under load. The coolant level was the one thing I didn't check before leaving home. DaveD (MC-8) | ||
| David Dulmage (Daved)
Posted From: 142.46.199.30 Rating: N/A |
With the revised board, I'm not sure how to edit posts. I actually added approximately 16 quarts of antifreeze and 16 quarts of de-ionized water to my cooling system. DaveD | ||
| Richard Bowyer (Drivingmisslazy)
Posted From: 70.105.143.139 Rating: N/A |
I installed two 12 volt, 16 inch automotive type radiator fans to help solve this problem. They were connected to a 190 degree thermostat mounted at the top of the radiator where it is the hottest. I alsoinstalled an indicator light on the dash to come on when the fans started. This acted also as an alarm that the engine was starting to get too hot. With the engine idling, there is very little air being pulled thru the radiator and if the engine has been under heavy load it seems to keep getting hotter for a period of time. Generally revving the engine up to a high idle will also help this situation. Richard | ||
| Marc Bourget Posted From: 64.142.42.176 Rating: N/A |
David, Keep in mind, MCI never designed and installed a "qualifying" cooling system pursuant to DD's 2-Stroke engine installation specifications. DD specs required a system sized sufficiently to handle 120 deg ambient conditions before it was considered a "qualifying" cooling system. MCI never met these specs. Thus the need for pallative efforts, like misters, etc. Factual support for my "band aid" claims. | ||
| Jack Conrad (Jackconrad)
Posted From: 207.30.189.94 Rating: N/A |
That's 8 gallon total added to the system. It sounds like that would allow the system to be low enough to qualify as overheating due to low coolant level. Unless you had a big air bubble in the system, I would check for an external leak. Could be as simple as a loose hose clamp. Can you park you bus where any coolant dripping under it will be noticable? Jack | ||
| David Dulmage (Daved)
Posted From: 66.78.120.187 Rating: N/A |
Jack, It's parked on a gravel pad right now at a camp where we lease a spot. I didn't notice any antifreeze underneath, but will be checking this out this weekend. Dave | ||
| Jack Conrad (Jackconrad)
Posted From: 207.30.189.34 Rating: N/A |
You might try laying some pieces of cardboard under the bus. Also check the area under the heater core as well as under the dash. Good luck. If you find nothing and the level stays up in the cooling system, perhaps it was a big air bubble in the system from when it was re-filled. Hope this helps, Jack | ||
| David Dulmage (Daved)
Registered Member Username: Daved Post Number: 124 Registered: 12-2003 Posted From: 142.46.199.30 Rating: N/A |
Thanks for the suggestions. I couldn't find any signs of leakage and went over all the hose clamps to ensure they were tight. The bus ran fine all the way home (about 100 miles) this weekend, with slightly lower temperatures that I am used to, at highway speeds varying from 55 mph on two-lane highway to 65-70 mph on 4 lanes. Dave Dulmage |