Getting the Heat out...

[RJ]

Iver -

FYI, on factory 8V92 installations, not only did MCI use larger/thicker radiator cores, they also used much larger squirrel cage blowers and a different diameter blower pulley.  Have you done the same?

Also, something that everybody seems to overlook, is that between the time you pull over, set the fast idle (you still have yours, don't you?), get out the IR gun, and open up the engine compartment, the temp will drop anywhere from 5-15 degrees.  Diesels cool when they idle!

I'd suggest one of the 270^o sweep water temp gauges for more accuracy, with a matching sender unit.  Install a matching one in the engine compartment, too, so that you can compare front/rear readings, as there will be a slight difference.

I agree with Luvrbus - 180^o thermostats will keep the engine a little cooler, plus give you a little more margin.  Your engine rebuilder may have used "da book" in choosing the 195s, but more than likely, those were truck specs, not bus.  They are different (no ram air effect, for example).

After all the little details, it will be time to make a run to the Okanagan!!


Doug -

Most folk will tell you that misters are really a "band-aid", except for very few instances.  If the cooling system is operating properly, they shouldn't be needed.

Driving techniques often contribute to overheating problems - diesels are different than cars, and because of that, expensive lessons sometimes happen!

FWIW & HTH. . .

[TomC]

I too believe that misters are a band aide-but-I increased my power output to 375hp with turbocharging-did increase the radiator to the largest I could install, and still it overheat.  I installed 15 misters from Home Depot running through my water system with a 12v solenoid valve, and I can at least control the buses temperature by slowing down and using the misters when the temp is above 90 degrees.  On this last trip where the temp was in the 80's, no misters were needed.  I do have to spray CLR on the radiator every so often to keep the calcium build up down since I just use regular tap water through the misters.  But without the misters, I couldn't do any summer driving.  The only other alternative would be an additional radiator-and I don't quite know where I would mount it.  Pure and simple-the Detroit 2 strokes are the hardest engines to cool. Good Luck, TomC

[Busted Knuckle]

Iver contact Don Fairchild!
Just last week while he was here @ my rally he & I were out running some last minute errands for the rally when he got a call from someone he knows with an MC9 that they were scraping out that had, had an 8V92 in it. He said the radiators, squirrel cages, gear box, pulleys etc were all in great shape and available reasonable!
I don't have Don's # handy but he is a member here on the board and runs a company in Bakersfield, CA called "Clean Cam Technology Service" or something like that I just call it "CCTS" fer short and have his # on speed dial in my cell phone but my phone is dead @ the moment and I don't have a charger on me! 

  BK 

[Iver]

Thanks everyone for all the thoughts and ideas. 

I think I will change the t-stats as a first step. My rear temp gauge is connected directly to the engine with a thermocouple. When the engine is fully warmed up it reads 195 degrees and never changes unless I turn the engine off or "hill-climb" as I most recently found out. If the t-stats are 195's then the gauge is probably fairly accurate.
My "book" shows two different thermostats. Probably that's where I got confused. Prior to Unit 37445....start to open 170....full open 185
                                                                                                                           Effective Unit 37445...start to open 180....full open 195

I know my rads are the larger ones. The previous owner changed them but I don't think he changed the blowers or the size of the drive pulley.

Speaking of "band-aids" such as misters, I had an old motor home a few years ago, front engine, gasoline, which had no heating problems except on long hill climbs. The factory built in two 12v fans in front of the radiator and when the temp increased to high the fans would come on, quite loudly, and the temp would drop dramatically very quickly and the fans would shut off. It would repeat that until we were no longer climbing. I thought it was a great system.

If misters do have some affect, then wouldn't fans work also?  Oh geez, I think I recall we beat this topic to death a few times before.  Oh well........

Anyway, I really appreciate all the help.
        Thanks, Iver.

[TomC]

On Misters- Here in Los Angeles, just about every bus company that charters to Las Vegas has misters on their buses.  It is the only way they can continue to operate when the temperature is above 110 in the summer.  Good Luck, TomC

[Busted Knuckle]

On Misters- Here in Los Angeles, just about every bus company that charters to Las Vegas has misters on their buses.  It is the only way they can continue to operate when the temperature is above 110 in the summer.  Good Luck, TomC

Of course unless it's a ladies only group right?
  BK 

[RickB]

It's becoming clearer every year that we as "bus folks" couldn't agree on anything if our lives depended on it.

To say that an Infrared Gun which is accurate to at least a 10th of a degree can't be used to diagnose cold spots in a radiator, or blockages in cooling systems or that it is not going to be ridiculously more accurate than the gauges which are 40 feet away from the source running through 30 year old wiring is just not even in the realm of a rational argument.

Go tell every mechanic that will ever work on your bus that he should just throw those inaccurate IR guns away and I'm sure he'll just walk to the garbage can and throw it away. NOT!!
I'll bet you there isn't one mechaninc worth his salt that doesn't go to his IR gun first when diagnosing cooling issues.

Like I said, we couldn't all agree that it's Wednesday today given enough time to think about it.

Rick

[Busted Knuckle]

Like I said, we couldn't all agree that it's Wednesday today given enough time to think about it.

Rick

Is that the day before or after Tuesday.
  BK 

[luvrbus]

Rick, Jim was just trying to inform the guys all IR guns are not equal and guys need to read the instructions they are not accurate off painted , shinny or oxidized  surfaces if not setup for it and most 50 dollar IR guns are not for the emissivity of all metals and surfaces the cheaper one are black only

good luck

[rv_safetyman]

Rick, I am not sure why I set you off.  Please read my post again.  I strongly recommend any IR gun for looking for differences in temperature.  For example, any of them are great for checking for hot spots in radiators and checking tire and hub temperatures for abnormal temperatures.  They are great for checking for hot spots in electrical cabinets/connections.  However, here we are looking at relative temperatures. 

Using the IR gun for ***absolute*** temperatures can be risky.  You say that they are accurate to one tenth of one degree.  I really need to see the source of that information before I buy that kind of accuracy.  We used to buy the very best units that money could buy.  We were lucky to get them calibrated within a couple of degrees and then we got drift.

I have a pretty good unit and it does not read to 0.1 degrees. 

I really don't want to get into a argument on this, but I spent a lot of time with top of the line products and I can assure you that I would not try to use them to calibrate a gauge. 

I am also concerned that reading the temperature of the exterior of a cast iron head or block does not equate to the actual water temperature.  I have done some playing with this concept using thermistors and could never get a good correlation. 

I think that calibrating the existing gauge with the sensor in a pan of boiling water would give a pretty good idea of the accuracy of the gauge.  The boiling point of water is reasonably accurate when corrected for altitude.

Jim

[luvrbus]

Jim, I paid 300 bucks for my Raytec and in the instructions manual it says with in 1%  why would it say percent and not degrees ?

[rv_safetyman]

After my last post, I thought I had better get up to date on IR equipment.  My experience was a few years ago.  I went to several websites.  Most rated their guns at +/- 2% or about 4 degrees possible error.  I did find some that were slightly more accurate (by about a half percent).  

I looked at Raytec's site.  The unit I have is shown at the link posted below (sorry for the length of the URL).  They do say that they set the emissivity for 0.95 (which is close to a black body and significantly different from metal surfaces which are closer to 0.1).  It has been too long since I worked with the impact of emissivity on temperature.  I do know that we always sprayed flat black paint of various parts when we worked in the field.  I will try to do some research on that issue later tonight.

http://www.raytek.com/Raytek/en-r0/ProductsAndAccessories/PortableThermometers/PortableThermometersSeries/MiniTemp-AutomotiveHandheld/Default.htm

So, if we can expect to be accurate within 4 degrees (on a part with an emissivity of 0.95), then I think it can be used for a reasonably good indicator of absolute temperature of the surface of the head/block/radiator/etc.

Being an engineer can be a terrible thing.  As I mentioned before, I am not convinced that the surface temperature of the part accurately reflects the coolant temperature.  This coupled with the emissivity issue kind of blurs how accurate the IR gun measures actual water temperature.  

Clifford, most instruments specify their accuracy (or tolerance) in percent.  

Jim

[rv_safetyman]

Wow, I am starting to feel like Sean here . (Sean knows me well enough to know that comment is a compliment).

I did some looking at emissivity.  One of the better sources is:  http://support.fluke.com/raytek-sales/Download/Asset/9250315_ENG_A_W.PDF. 

That document talks about emissivity error of up to 10% of reported temperature with some metal objects.  A chart in the document suggests the error is more likely in the 3-6% range. 

The document emphasizes calibration of the specific surface to be measured using a thermal couple.

They also emphasize that measuring the surface temperature of a vessel does not necessarily correlate directly with material in the vessel.   

Given the tolerance of the gun, the emissivity issue, and the possibility of some delta temperature error (surface of block vs. coolant), I continue to be concerned about using the device for calibration.

Jim

[RickB]

Jim,

My observation was not intended to appear that someone had set me off and I apologize if I came off like that.

It really does seem sometimes like there are absolutely no absolutes to a country with 300 million and a planet with over 6 billion. You will always find disagreement because it is inherently more probable given a larger pool to fish in.

The argument of motor vs engine, biofuels, svo, wvo and fossil fuels, potatoe vs potato. is just wearying after a while.

I believed when I posted my response and I still believe that IR guns are far more accurate than 30 year old wiring and gauges to get actual real time data on engine/motor temps but I realize that as I write that someone out there is trying to find a way to marginalize that statement. One needs look no further than the off topic politics arguments to realize it truly does "take all kinds of people to make a world".
I think this is the reason we lose so many really good and knowledgable people here is they get tired of never being right although their own experience tells them they are indeed right.

My last bus, a 4905 with a 6v92, started overheating one day. $2500 later and a new radiator, water pump, stats, and coolant we found it was a faulty gauge. How did I finally diagnose it correctly?

After spending all that money I stopped at a truck shop in Kansas and bought a guy an $8 pizza and he went for a 5 mile ride in my bus. He stood by the door and I pulled the bus over and voila! the bus gauge was reading 30 degrees hotter than his IR gun.

That was my expensive experience, hands on, with trusting the gauge in my bus, and yet I know sure as I'm sitting here that someone will read this and try and convince me otherwise.

There's the rub. When our experiences don't match up, our results don't match up and then the "truth" that we have experienced with our own eyes and ears comes into contact with someone else's "truth" and we end up cancelling each other out in argument.

The moral of the story is Busnuts would have made great debate team members.

Iver, grab a pizza, go to your nearest diesel shop, find a guy with an IR gun that is in the $200-300 range and give him a ride in your bus. It may be the best $10 you ever spent.

Once again Jim, no harm intended.

On a lighter note I will be contacting you about purchasing a couple of the extinguisher units you sold to Brian Diehl and Craig "beer butt" Shepard, You should hire thise guys to represent your company they are darn good at selling your products LOL!

Hey come to think of it. that is one thing I reckon we could all agree upon:

"Craig Shepard's beer butt chicken is a wonder of culinary delight that should not be missed"

Oh, wait. There must be vegan bus owners out there!! Oh the humanity.

All the best..

Rick

[rv_safetyman]

Rick, thanks for the positive note.

I mentioned earlier that being an engineer can be a terrible thing.  When I was a young engineer, I would apply my textbook knowledge to a situation and pronounce "you can't do that" to a customer.  More than once, he would politely grab my arm and take me out to show me that "it" was working quite well.  I suspect that some wiser engineers set up the situation to "finish' my real world education

When I see folks ask questions about slides or towing big trailers, my engineering background suggests several engineering issues that could cause big problems.  I try to post my concerns as one person's opinion.  My attempts are always intended to emphasize that the writer should proceed cautiously.  Each time I post, I get a ton of replies that folks are, indeed, doing it and not having any issue.

My goal is always to avoid being argumentative.  Rather it is to play devil's advocate so that the reader gets balanced input.  When I step over the line, folks are not reticent about letting me know

Jim