160 thermostat vrs 180

[Jim Hardesty]

I'm in fresh water and was wondering what the advantage of going to a 180 degree thermostat would be?  Has anyone done that and what happens in the real world?
Jim

[KWKloeber]

Jim
Diesels run more efficiently at higher temp.
The tractor TStat is 180, the marine (univ/Wb) TStat is 160 (i.e., they don't offer a freshwater option.)

I suspect you could restrict the cooking flow a little bit at a time until the engine temp settles out to 180 to try it.

[Stu Jackson]

I'm in fresh water and was wondering what the advantage of going to a 180 degree thermostat would be?  Has anyone done that and what happens in the real world?
Jim

Jim, I had two 160s years ago, one in my engine and another spare.  I paid it forward by giving it to a fellow C34 skipper, and then installed a 180.

That was in 2005 or 6.  I've been running the engine with that ever since, over 1,000 hours.

what happens in the real world?  Nada, zip, zilch, all is fine.

[Ron Hill]

Jim : I was in fresh water 1/2 the time and salt water the other half for 15 years.  The 160F is what was always was in there (& still is) with no overheating.  Never noted the difference in performance!!

Seems to me that if there is a "runs better" or "More efficient" in the 2 different temperature thermostats that it should be measurable and written up in the manuals by the manufacturer!?!

A few thoughts   

[KWKloeber]

Jim : I was in fresh water 1/2 the time and salt water the other half for 15 years.  The 160F is what was always was in there (& still is) with no overheating.  Never noted the difference in performance!!

A thought

Ron:  Non conprendo, senor. 

How can you compare (a difference in) performance of the diesel if you never ran the 180F TStat?

-k

[Ron Hill]

Ken : Let me ask you this question? : What should/would be the notable difference in engine performance between the 160F and the 180F thermostat????
 
Guess if I tasted coffee at 160F and 180F, both would burn my lips.  So I'd probably prefer the lower temp 160F!

 
A thought

[KWKloeber]

Ken : Let me ask you this question? : What should/would be the notable difference in engine performance between the 160F and the 180F thermostat????   

Ron

Ahhh redirection with an irrelevant question (irrelevant whether there is or is not a difference that can be "felt" by the driver)  The point is, how can you state that you see no difference between coffee at 160 and 180 when all you ever drank is coffee at 160?

But to your question -- it has been my understanding (from surveyors, truckers, diesel mechanics) that diesels "run better", are "more efficient" at a higher temp. I don't have data or a white paper to back that up, just 3rd-hand.  We know that a diesel can't get to proper operating temp unless under load -- and also they "run better" under high load (ask any trucker.) 
I suppose there's different meanings to "run better" and "efficient" -- but a diesel needs to be hotter (again, just my understanding) to prevent incomplete combustion (dunno - maybe high emissions and soot and pollution and raw fuel out the exhaust?) and issues in the engine itself (maybe carbon build-up from incomplete combustion?).

I also go by what Kubota recommends/supplies for these engines (but Wb installs a 160 (to reduce precipitation issues in saltwater.))

From the original M25 Service Manual talking about our "radiator" (Universal hadn't removed the tractor references): 
Thermostat opening temperature - Approx. 82°C (180° F)

So I'll ask a question - Why would Kubota design the engine to operate at 180?  Just coincidence and it could be 160 or 180?  Maybe.

[KWKloeber]

Additionally - see Page 2 of Universal's original M25 Service Manual

ENGINE OPERATING TEMPERATURE  175⁰ to 190⁰

I don't see why Kubota (the manual was copied from Kb's engine manual) would design them to run in that temp range unless there was a reason for it.  Maybe they just had to "pick something" and 180 it was?

[Paulus]

Jim, I did change from 160 to 180.  It actually read 185(with engine running)  I am also in fresh water and did not notice any difference in performance.  The engine room felt warmer but no scientific evidence.  Half way through the summer, I took out the 180 and replaced it with the 160.  My thinking was that with the 160, I had more time if the engine should overheat due to weeds in the intake. 
Paul

[glennd3]

Am I missing something here? If you are using a HX what difference would it make salt or fresh water as neither get to the thermostat because it is a closed system.

[KWKloeber]

Glenn

Yes (you are missing the link.)

The elbow joint is connected to the arm bone.  Or in this case, the seawater injection wye @ the muffler and Hx seawater side are connected (thermally) to the engine coolant loop.  The cooler the engine coolant, the cooler the seawater after the Hx.  Or conversely, hotter coolant causes hotter seawater to precipitate out and deposit the gunk at places we don't want it to end up.

It's another of those compromises we all read about re: "boating."  Controlling one negative can lead to another negative and it becomes a teeter-totter.

It's kinda strange that some owners have no problem at all with deposits and some have had near-totally blocked injection wyes, presumably the same seawater salt content and same Tstat.  Maybe seawater temp is the controlling factor?

[Jim Hardesty]

I did change from 160 to 180.  It actually read 185(with engine running)  I am also in fresh water and did not notice any difference in performance.

Thanks Paul,
That answered my question.  So....Running hotter "in theory" should give more efficiency and power, but is not enough to notice in the real world of C34.  Somewhat warmer in the cabin, not good for most of my sailing season.  Perhaps would be something to do if Lake Superior was my sailing grounds.
Jim

[Jeff Kaplan]

I've been running a 160*  therm in my 1986 M25 for the past 15 years. Temp averages around 175* when I motor at 1800rpm's, no problems. If you have a 160 therm, stay with it.