Use use a restrictor in the race car. it takes place of the thermostat and puts a smaller hole size there. allowing coolant flow all time but not runing it too cold at all. and you dont want a big money motor to blow up just because your thermostat stuck close. dont know if they make them for sleds?
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anyone have the pros and cons of running without t-stat?
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part of the motor working proprely is the operating temp of the engine. the pistons and the cyl need to be at a proper temp to control the piston to wall clearance. a cyl that runs too cold can cause the piston to cyl clearance to be too tight and a seizure will occur this is refered to as a "cold seizure" . This is why it is important to warm the engine up before using the motor hard. When the engine is cold the piston will heat up much quicker than the cyl due to the size of the piston being way smaller than the cyl and cooling system. when you warm the motor up you are allowing the parts to expand at the same rate. A aluminum piston will grow and become larger when it heats up. the purpose of the thermostat is to keep the engine at the proper operating temp at all times. with no thermostat you have no ability to control the temp and in turn the internal clearances and on a really cold day you can cold sieze a motor that has been warmed up . In the summer we race yamaha 2 stroke 250cc tz race bikes, these bikes make 90 rwhp and have no thermostat. we have to tape the radiators with duct tape to maintain a water temp of 180 degrees at all times. If we don't we run the risk of cold siezure or over heat. you have no ability to control the temp in a sled. In my opinion removing the thermostat is not an option on a trail sled. I have a mod sled with no thermostat and the restrictor which i promptly removed and instaled a thermostat I have concerns about the thermostat failing so i replace them every year and i instaled temp guages on all my sleds.dgcat said:anyone have the pros and cons of running without t-stat?![]()
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Mine failed when I was up in northern Ontario on my '03. Coolant kept recirculating from top of head back to expansion bottle allowing very little to go out through exchanger, but just enough for me to get back. Found pieces of it all the way to impeller. I noticed it having issue on my temp guage creeping up. I've seen it in a coupler of others sleds less than a year old. Not a very durable product and I haven't had had problems with them on my previous sleds. Just another 'Ring Thing' to be aware of!
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-Grover
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I agree 100%. Running cooler than the engine was designed for will cause accelerated wear of the piston and cylinder. Maybe it will not seize but I will never run a motor that I want to run efficiently for the long term without a stat. Large temp variations like we see here in central Canada will cause it to run very cool in -40C without a stat, shrinking the cylinder, and then when the weather warms up, expanding the cylinder, there is a distinct possibility that there will be blow by and significant power loss because of the increased wear/clearances.kyle797 said:part of the motor working proprely is the operating temp of the engine. the pistons and the cyl need to be at a proper temp to control the piston to wall clearance. a cyl that runs too cold can cause the piston to cyl clearance to be too tight and a seizure will occur this is refered to as a "cold seizure" . This is why it is important to warm the engine up before using the motor hard. When the engine is cold the piston will heat up much quicker than the cyl due to the size of the piston being way smaller than the cyl and cooling system. when you warm the motor up you are allowing the parts to expand at the same rate. A aluminum piston will grow and become larger when it heats up. the purpose of the thermostat is to keep the engine at the proper operating temp at all times. with no thermostat you have no ability to control the temp and in turn the internal clearances and on a really cold day you can cold sieze a motor that has been warmed up . In the summer we race yamaha 2 stroke 250cc tz race bikes, these bikes make 90 rwhp and have no thermostat. we have to tape the radiators with duct tape to maintain a water temp of 180 degrees at all times. If we don't we run the risk of cold siezure or over heat. you have no ability to control the temp in a sled. In my opinion removing the thermostat is not an option on a trail sled. I have a mod sled with no thermostat and the restrictor which i promptly removed and instaled a thermostat I have concerns about the thermostat failing so i replace them every year and i instaled temp guages on all my sleds.dgcat said:anyone have the pros and cons of running without t-stat?![]()
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There was another thread on this topic some time ago and there were some very good points made about stress and strain that MAY occur on the engine due to this mod as well. Also in that thread someone commented that the power your engine develops comes from heat and the more heat you pull from the engine unnecessarily the less power it will generate. Again, 100% correct and I have the heat equations to prove it. Tighter piston to cylinder tolerances may give you some of the power back but as a Power Engineer these heat loss principles are in total agreement with what I was taught, and the resulting increased wear has been confirmed by both of my Journeyman Mechanic friends.
I am new to sledding but have done alot of my own wrenching on 2 and 4 stroke bikes etc. so I'm not saying that I know everything about these engines (because I most certainly do not!) but from what I have been taught as an energy conversion specialist and from what my friends who are "in the know" tell me I will not remove my stat. Stats IMO are very simple and reliable devices that will usually give you signs on a temp gauge that they are going south long before they fail totally. Sudden failure does happen though. Perhaps I am just choosing the lesser of 2 evils?
I could go on for pages and pages here but I Doo welcome all input on this subject as I most certainly still have some learning to Doo! The people on here are some of the greatest and are what make this site so darned addictive!
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Solid Post Tweener! Like I said, I could go on and on (ad nauseum.) about this subject, but I think you did alot better on that aspect than I could have.
It may seem like a fairly simple subject, but there is more to it than first meets the eye IMO.
I'd be very interested in more opinions and info. from Kelsey at RKT as I have his drop in kit and head coming and respect his opinion immensely.Was that sucking up or what!
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BTW I singled Kelsey out only because of my dealings with him but I have just as much respect for Big John or Bill Cudney and the years of "real world" experience they have over little old me.
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It may seem like a fairly simple subject, but there is more to it than first meets the eye IMO.
I'd be very interested in more opinions and info. from Kelsey at RKT as I have his drop in kit and head coming and respect his opinion immensely.Was that sucking up or what!
BJ,
So if I'm reading you right, using Smitty's kit w/ restrictor will keep water temps at around 100 while removing stat altogether would keep temps at about 80? Union Bay recommends removing it altogether. I'm thinking of going that route since I have the shorter coolers on the '03 and have higher water temps anyway. Your thoughts please.
Thanks!
G
PS - For the doubters out there: I guess BJ, Bill Cudney, Kelsey, and Mark at Union Bay Racing just don't know what they're talking about???
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So if I'm reading you right, using Smitty's kit w/ restrictor will keep water temps at around 100 while removing stat altogether would keep temps at about 80? Union Bay recommends removing it altogether. I'm thinking of going that route since I have the shorter coolers on the '03 and have higher water temps anyway. Your thoughts please.
Thanks!
G
PS - For the doubters out there: I guess BJ, Bill Cudney, Kelsey, and Mark at Union Bay Racing just don't know what they're talking about???
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