T-stat or not T-stat??

[rmk addict]

I have 09 800 RMK, (fix, PCV, scratchers)

just wondering if anybody out there is running without a T-stat?

and what kind of numbers you are seeing for coolant temp?

 

[milehighassassin]

I am running without one, I have a modded stock pipe and a high compression head. Key is to take it easy on the sled until you get up to temp. I am considering going back to a thermostat but will probably drill a little of it. Mostly because I am going to a Wiseco piston and am afraid of a cold seize.

 

[1fastD8]

I have 09 800 RMK, (fix, PCV, scratchers)

just wondering if anybody out there is running without a T-stat?

and what kind of numbers you are seeing for coolant temp?

PC3, clutch kit, scratchers and a snow flap mod to make the flap wider. I cut the body out of the t-stat for this season and have had no issues at all. I start-up and by the time I have all me gear on its running about 90-100 degrees. I run with the scratchers down all the time and usually stay in the 120-130 and a fair amount of time in the high teen range as well, with regular trail riding. However, I have seen more consistant temps since doing the snow flap mod.
my opinion, is to get rid of it...

 

[richracer1]

FWIW, I'm using SLP's 777 kit, so big bore & high-comp head and I'm still using a t-stat. Running on the trail with the slide kick scratchers (w/carbide tips) down, a 24" flap, and using Engine Ice for coolant, my temps are usually about 120 - 122. Get into some powder and it'll drop to 117 - 119.

 

[red99powerstroke]

My 860 carls says not to run a t-stat but down the trail with the scratchers up it will get to 150, put the scratchers down it will plumit to about 80. In powder it also runs only about 80 and carls says thats about right so I am only doing what carls says.

 

[rmk addict]

Anybody know what an ideal coolant operating temperature is? I usually run in the 120s with scratchers.

 

[shmuckaluck]

Hey guys,
Running without a Tstat doesn't make any sense, it's there to hold water in the coolers to get the heat out, I have never seen a time when taking out the stat is a better option, with sled or cars. change temps maybe.

 

[milehighassassin]

Hey guys,
Running without a Tstat doesn't make any sense, it's there to hold water in the coolers to get the heat out, I have never seen a time when taking out the stat is a better option, with sled or cars. change temps maybe.

The lower you can get the coolant temps the more horsepower the 800 cfi4 will produce. I'd say true on any motor. Once coolant temps rise too much timing will automatically be pulled. Keep coolant temps down and you can advance timing. It's been dyno proven.


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[mike_s]

If you run without a thermostat, put a restrictor in its place. Take an old thermostat and gut it and replace the outer ring back into the housing at least. There has got to be a differential pressure between the coolers and the engine, otherwise you will get cavatation, hot spots and possibly overheating. Running without one period is completely pointless IMO, if the engine is running hotter than you want then get a thermostat that is of the range that you want it to run. Seems pretty simple to me. The biggest problem with running without one, or without a restrictor of some kind, is the hot spots that will develop. The overall coolant temperature will seem to be fine, but in that one spot where the coolant is cavatating it will be considerably hotter. Enough in many cases to cause damage and there will be no warning signs. Or the pump will cavatate and the engine will overheat. Its not about slowing the coolant down so it can transfer the heat so much as it is about keeping higher pressure inside the engine block to prevent cavation and hot spots.

 

[alankb]

Mine failed today!

So, I have one more day of riding here in the Uintas, and my t-stat failed today. I removed it. Surely I will be fine for one more day of riding?????

Oh, this is on my '07 600 RMK.

 

[milehighassassin]

You'll be fine. Just bleed the cooling system.


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[alankb]

THANKS!

I seem to remember "gutting" the 'stat on my 800, but it doesn't have the digital gauge so I don't know what it runs. I hardly dare run that thing even though it's all new again! Stupidest thing I ever seen is that little water/oil pump belt! Lost it twice!

 

[1fastD8]

Did 1200 trouble free miles this year without the t-stat. Temps with scratchers stayed in the 120's. I've been told that best hp is below 130 and everything above starts loosing hp.

 

[sledhed]

And then there is the Gizmo (sp?) coolant bypass setup where they keep the temps at a constant 145 and limit the cold shot when starting up after sitting a bit (where it drops from 120+ degrees to 80 or 90 on startup), and they claim more HP that way? IIRC, they even had dyno charts to show it (in another thread here on snowest somewhere).

 

[winter4ever]

I dont understand how removing the t stat is going to lower over all temps.
Once it is open, Im guessing it is somewhere in the 115 degree range you are flowing coolant through the cooling system. Its there to prevent that shock of cold water to your hot engine, like startups after sitting for a little bit. If you sled is running in the 145 degree range then your t stat is open, it not being there isnt going to change anything, right? Ive been in very few situations where a good set of scratchers couldnt keep my sled below 125, they work the best. btw, im not trying to flame, its just my opinion and I am open to being proved wrong

 

[milehighassassin]

Motor never has a Chance to heat soak. I think they open higher than 115.


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[MARV1]

More consistant temps running without one, just pulled mine and my son's out. When they fail you will overheat quickly. Always did it on my Edges and GenII's without problems. They were put in to allow quicker warmups for those that are impatient.

 

[milehighassassin]

Maybe if I get bored, I'll drop mine in some water on the stove and see what temp it opens up at.

 

[harrysmith500]

Maybe if I get bored, I'll drop mine in some water on the stove and see what temp it opens up at.

Please do and report.

I'm thinking ill do diamond Dave's t stat mod. He drills 2 holes for Byoass but leaves The functioning tstat in place.

 

[milehighassassin]

What does he drill holes with? Thermostat is pretty small.


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