Coolant Pressure Control Cap
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03-07-2007, 18:02
Post: #21
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Coolant Pressure Control Cap
Yeah, me to it was 1973. I have been on the yacht site as part of my little
personal study. I have a good friend who is a very good yacht mechanic, and a partner in my airplane, we hanger fly about boats and aircraft and drag bikes every Sunday morning a 8 AM. Sometimes we talk about other things. ???/? How do I know if the engine thermostats cycle? I only see them cycle upon cold start up and driving during the first say 15 minutes. Otherwise, I can place the fan in override during Winter resulting in the temperature value being stable (fixed)at around 170-175 degrees on the flat at 68 mph. 170-180 degrees is the thermostat low(opening value) depending on the thermostat value installed in the coach, according to DD service manual. Kinda sorta confusing. One would think the thermostats would cycle in cold weather when coolant temperatures approach or are equal to normal opening value(170-180). I cannot make it happen at any speed, cannot make it happen at idle or high idle, and I have tried it at 32F with the fan override on. Then, I read about Winter fronts and wonder why they are needed if the thermostats cycle properly. Winter fronts are typically used to increase cabin heat. 170 degrees is hot enough for me if the thermostats cycle. The thermostats may be slowly closing restricting water flow causing hot spots, but I do not see the evidence yet.. Perhaps I will when the engine blows, but I do not expect that to happen. The foregoing is why I think I am OK with a 190 degree Alarmstat. I'll take the 6% heat reduction for the drive train components under the circumstances. It is also why I stated I might try a 185 degree, perhaps I would be pushing my luck. I probably will not make that change. Then again, if the thermostats do not cycle, why not? Why not is the answer I am searching for and haven't yet found. Something to think about, particularly when you pull the mountains. 6% temperature variance is a bunch. Wonder if the radiator water flood will cause the thermostats to cycle. Leroy Eckert 1990 WB-40"Smoke N Mirrors" Niceville, FL ----- Original Message ----- From: Chuck Wheeler To: WanderlodgeForum@yahoogroups.com Sent: Wednesday, March 07, 2007 9:15 PM Subject: RE: [WanderlodgeForum] Coolant Pressure Control Cap I wish! I graduated about 33 years ago! Sounds like you have done your homework. How do you know it the thermostats cycle? Most of the time you see a slight drop on the initial opening of the thermostat(s) as the cold coolant from the radiator is let in. After that there is a lot of mixing going on and the and the radiator is acquiring heat from the charge air cooler, transmission cooler etc. Boats are a different animal; those engines are under a constant heavy load all the time. You have to run a lower average temperature to keep the peaks within range. They usually have a different thermostat housing that bypasses a lot of water as they have an unlimited supply of cold coolant. There is an interesting article at: http://www.yachtsurvey.com/comparing_diesel_types.htm that is somewhat related. - Chuck Wheeler - 82 FC 31 SB Fort Worth, TX _____ From: WanderlodgeForum@yahoogroups.com [mailto:WanderlodgeForum@yahoogroups.com] On Behalf Of Leroy Eckert Sent: Wednesday, March 07, 2007 9:00 PM To: WanderlodgeForum@yahoogroups.com Subject: Re: [WanderlodgeForum] Coolant Pressure Control Cap Thanks for the response Chuck. According to the content of your post you surely must have just recently graduated from college because your info does almost perfectly follow my DD manual. 'lol What got me started with this boondoggle was a failing Alarmstat in mid September last year. It was intermittent and caused the engine temperature to go above 200-205. At that time I estimated those temperatures using the original gauge. I have since installed VMSps and can now receive actual data from the DDEC II. It turns out that my gauge is very close to actual temperatures. In mid September I had no need to operate the chassis a/c. So I changed the sensor to its published value, 195 degree and found that it did if fact cycle around 195-205 degrees. During the time the original Alarmstat was acting up I made notes of temperatures of all the drive train components while operating with the fan in override because I did not care for the temperature climbing above 200 degrees. I found that water temperature stabilized at around 170 degrees with cool OAT and the fan in override. No cycling of engine thermostats was evident. When I noticed the new alarmstat pushing the temps to the upper limit I began to wonder why. I contacted BB and asked questions. I contacted Southern Power and asked questions When I wasn't satisfied with the answer, being the old backyard Chevy 301 (283 punched out) mechanic that I am I purchased a DD service manual set and started researching the cooling portion. There are several set ups available including shutters, on /off fans, modulating fans etc. There are two thermostat ranges. The only time I see my thermostats themselves cycle is when I begin a trip. The temperature will climb to about 195 degrees, cycle back to about 170 and then get on the Alarmstat cycle. I see the same thing happen in my Cummins SLT pickup, minus the Alarmstat. I have tried to force the thermostats to cycle this winter( the only time they will ever cycle if they are going to do so) and have not been able to force it to happen. In summer, the chassis a/c is on with the fan running full RPM and the temperature is stable at 190, because the Alarmstat is bypassed in this configuration. I decided to change to a 190 degree Alarmstat to see what would happen. I found the I received temperature reductions in drive line components of about 6%. I have not seen any adverse reactions to the engine----- Yet, and I do not believe it will cause a problem based on the DD manual, and its published temperature ranges. Since you were right on, I'll send you the two pages to look at , if you have time, and please give me your input to see if I am ok here. <<:>> I would need to do that off forum. Interesting side note. I was on a boat last week with an 8v92 turbo. Those engines are worked under power all the time and his water temp was steady at 180 degrees. That was raw water through a heat exchanger. That makes me wonder more about all of this. Leroy Eckert 1990 WB-40"Smoke N Mirrors" Niceville, FL ----- Original Message ----- From: Chuck Wheeler To: WanderlodgeForum@ yahoogroups.com Sent: Wednesday, March 07, 2007 9:38 AM Subject: RE: [WanderlodgeForum] Coolant Pressure Control Cap Leroy, I am pulling at my memory on this one and have been thing about it since I read your posts, but I spent one summer while in college working in a shop that rebuilt DDs. I think some of the old timers got tired of all my questions! At that time there were shutters in front of the radiator to control the temperature. There were also thermostats in the engines. The reason I was given was that the DDs were two cycle engines; I think they were Xv71s, and the function of the thermostats was primarily to get the engine up to temperature quickly to prevent fouling. The shutters controlled the running temperatures. The shutters were set at a higher temperature than the full open point of the thermostats so there would be full coolant flow through the block to prevent hot spots that would occur if the flow was restricted. These were trucks so the shutters controlled the "ram" air, a bus is different, but cycling the fan has the same effect. The other thing I remember was that the DDs being two cycle engines did not have the intake stroke to cool the pistons. This is accomplished by the scavenging and is why the condition of the charge air cooler is very important. Your temperature gauge only shows the average temperature of the engine coolant. I know there were some interesting discussions with DD factory engineers when we were doing custom work on specialized construction equipment. They wanted to keep the average temperatures up and the peak temperatures down. I would expect that since BB was a builder and customer of DD that there was consulting with the factory on the design of the cooling. I do remember lunch time discussions about the condition of charge air coolers that the customer would not repair, or someone who had blocked the shutters open to make their truck run cooler, and how long it would be until we had the equipment in for a rebuild. If you have one of the 4 cycle DDs this probably does not apply. - Chuck Wheeler - 82 FC 31 SB Fort Worth, TX _____ From: WanderlodgeForum@ yahoogroups.com [mailto:WanderlodgeForum@ yahoogroups.com] On Behalf Of Leroy Eckert Sent: Monday, March 05, 2007 6:13 PM To: WanderlodgeForum@ yahoogroups.com Subject: Re: [WanderlodgeForum] Coolant Pressure Control Cap Thanks: I have not experienced overheating problems, I am picking at it, and I just do not yet understand why BB and their engineers specified an Alarmstat fan controller which pushes the water temperature to the upper limit. That is why I changed my Alarmstat to a lower temperature. I may yet try a 185 degree just to see if it interferes with the engine thermostat operation. I have a feeling that it will not. If I can get my coach to run on the flat in the mid-range of DD specifications, an average of 185 degrees I am going to do it. As always, thanks again for the input. Again, I am posting what I am doing and do not suggest any one else try this unless you understand how your particular system works. So far mine is doing fine. If I blow my engine up that is my problem. If my theory works, I'm happy and I will report. For those who do not know, the Alarmstat, funny name for a part that actually forces the water temperature up, is the part that cycles the hydraulic fan on and off, assuming your chassis a/c is off and the fan override is off. That is how mine works on the WB-40 I am going to install a supplemental water spray system, just in case I need it. Leroy Eckert 1990 WB-40"Smoke N Mirrors" Niceville, FL ----- Original Message ----- From: Pete Masterson To: WanderlodgeForum@ yahoogroups.com Sent: Monday, March 05, 2007 12:55 PM Subject: Re: [WanderlodgeForum] Coolant Pressure Control Cap I had some overheating problems with my Series 60 powered unit on my homebound trip after taking delivery in Texas... Upon opening up the radiator, it was found to be 2/3 filled with oily- dirt pulled into the radiator. This could not be seen from the outside due to the charge air radiator that's located in front of the water radiator and it could not be seen from the inside due to the metal shroud around the fan. The area under the fan was open and clear -- it was everything else that was blocked up. Although a simple cleaning of the radiator could have resolved the problem -- I elected to replace the radiator core with a more efficient design (since about 1/2 the cost was the labor to pull the radiator). My current temperature readings are quite similar to yours -- except the water temperature has yet to go much above 180 -- and my retarder is exhaust based, and doesn't have a temperature gauge. When the radiator was replaced, the radiator service replaced the cap ... it's rated at 15 lbs. I do lose about 1 quart of radiator water each trip while using the chassis heat. There's a minor leak somewhere, but I haven't found it yet. When the chassis heat isn't used, then I don't seem to use any radiator water. (I carry a couple of spare gallons of premixed coolant along...) Pete Masterson aeonix1@mac. '95 Blue Bird Wanderlodge WBDA 42' El Sobrante, CA On Mar 4, 2007, at 6:09 PM, Leroy Eckert wrote: > <Snip> > I like my drive train component temps now. > > Engine Oil-215 > Water Temp-Cycles between 180-190 > Transmission Temp- 170 > Retarder Temp- 220 > All recorded in flat conditions at cruise speed of 68 mph, pulling > a 20ft trailer w/car. > > I do not suggest you try anything unless you fully understand your > system, I'm simply reporting what I did. > The foregoing presumes that all system components are in proper > working order. > > My next project is to install MH's water injection system so when I > climb the mountains next summer I'll have a water flood just in case. > > Alright, fire away, I have Redneck engineering paperwork on this > one. LOL lol, lol [Non-text portions of this message have been removed] [Non-text portions of this message have been removed] [Non-text portions of this message have been removed] [Non-text portions of this message have been removed] [Non-text portions of this message have been removed] [Non-text portions of this message have been removed] |
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