| Author |
Message |
McSwain
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, June 02, 2006 - 8:10 pm: | |
I have a 8v92TA DD if i change my thermostat to a 170degree will the D deck pick up the temp change from the 180 thermostat. I have one person saying the DD may have problems with this But the other guy who I value his opinion more says no problem. Mexican stand off!!! need a tie breaker! |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, June 02, 2006 - 9:53 pm: | |
Why would you want to change to a 170 degree thermostat? Everything I have ever heard is that the 8V92 is designed to operate best at 180 degrees.
If you are having an overheating problem then changing to a lower rated thermostat will not help the problem, in my opinion.
Richard |
mcswain
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 03, 2006 - 5:16 pm: | |
The two thermostat are 170-187 0r 180-197 overheating is a problem on long uphills like one 15 miles grade in mexico. I have a 9 blade fan installed, new rad. pump is going to be changed. |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 03, 2006 - 5:37 pm: | |
Regardless of the thermostat you have installed, only so much liquid can get thru it when it is open. Even if you put the 170 thermostat in , you would still overheat on a long pull like you are talking about.
I would suspect that you need the radiator cleaned and rodded or some other portion of the cooling system is creating a problem.
Of course, the other problem is a heavy foot and operating in too high a gear.
I am not familiar with the DDEC, but if you can manually shift down to a lower gear and keep the rpm's up higher, the DD will be much happier.
Richard |
Ron Walker (Prevost82)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 03, 2006 - 7:37 pm: | |
I agree with Richard putting in 170 thermostats won't fix your problem. I run 6% grades at 65 / 70, with my 8v92ta with no heating problems... You need a bigger rad and fan? better rad shroud?... something.. but it ain't thermostats.
Ron |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 03, 2006 - 9:31 pm: | |
One thing I might add that some people do not seem to realize.
The purpose of the thermostat is to bring the engine up to normal operating temperature as quickly as possible and then to maintain it at that operating temperature by opening and closing a small amount to control the water flow thru the engine.
Once the engine temperature exceeds the rating of the thermostat, then the thermostat has no function whatsoever. It is fully open and that is all it can do.
Then it is time for the fan, radiator, water pumps, hoses and any other ancillary cooling items to do their job.
Richard
(Message edited by drivingmisslazy on June 03, 2006) |
Marc Bourget
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, June 04, 2006 - 9:35 am: | |
Volumes of water, separate (or within eachother)of significantly different temperature don't mix well. This impedes heat transfer.
If you don't "grok" this, heat water to boiling in a glass and dribble chilled or ice cold water (just the water, not the ice) into the warm glass while it's standing in front of a light source. Youl'll see almost a black line showing the interface between the different temp water until it, over time, equalizes temperature.
The interface can resemble something like cigarette smoke,IYKWIM.
One thing a thermostat does is "slow" the flow down to promote heat transfer by promoting mixing and dissapation of the hot into the cooler coolant.
[This deals with heat transfer but is different from the micro vs. large bubble effect I've mentioned elsewhere] |
Marc Bourget
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, June 04, 2006 - 9:43 am: | |
Forgot to mention, the same thing can occur in reverse in the radiator.
That's one of the reasons to keep the coolant "speed" through the cooling tubes high enough to generate "turbulence" within the tube to insure mixing at the tube/coolant interface-improving heat rejection. |
Richard Bowyer (Drivingmisslazy)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, June 04, 2006 - 11:45 am: | |
Marc, maybe that is one of the reasons for the thermostat bypass, to assure some water is always flowing thru the engine and radiator, regardless of cold temperatures.
I really doubt that there is much water separation in the radiator since there is no "significant" temperature differential between the inlet and outlet temperature, (except when the engine is cold), and then it doesn"t matter. LOL
Richard |
Marc Bourget
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, June 04, 2006 - 2:08 pm: | |
Just chatted with Bob Sheaves. Thermostats "cycle" flow rates in order to improve heat exhange. The speed/turbulent flow through coolant tubes is important in small radiators used in airplanes.
I got my original exposure to this factor of radiators from the legendary aircraft designer, John Thorp. |