2018 600 and 800 HO Production Upgrades

[Lenn Johnson]

Polaris today announced a series of running changes to its 2018 model lineup that will affect most of its snowmobiles for the coming winter. Most global are some changes to the 800 H.O. and 600 Cleanfire engines that power the vast majority of snowmobiles for the brand, but updates to its crossover and mountain sleds will likely have the most noticeable changes for new sled buyers.

Starting with the 800 H.O., Polaris is switching to a new thermostat that gives the sled a lower running temperature of 110 degree F vs. the 125-degree thermostat that was previously used. This will result in more consistent engine operation and a bit more margin against overheating, the Polaris announcement said, noting that the new thermostat increases the main circuit flow by 12 percent and the bypass flow by 9 percent. The engine also gets an updated exhaust gas temperature (EGT) sensor that is said to be more durable, with improved/more durable connector and sensor element.

Both of Polaris’ liquid-cooled snowmobile engines — the 600 and 800 — will now come with sealed cross-shaft cavity crankcases with additional lubrication and increased durability, plus an improved MAG end seal for better sealing and increased durability.

 

[big tom]

So can the lower thermostat be used in the 2017 or is the ecm set up for opt running at 125 degrees?.

 

[Brock]

As long as they didn't change the thread bung for egt

As far as the head with lower t stat. You'll need to buy the whole head assembly to get the new t stat as I can see

 

[Brock]

I spoke to soon, lol

The egt bung thread size has changed. That's gonna make pipe guys mad . Especially the ceramic coated pipe makers . Not easy to weld a new bung on without ruining coating

 

[Chiefcheese]

I spoke to soon, lol

The egt bung thread size has changed. That's gonna make pipe guys mad . Especially the ceramic coated pipe makers . Not easy to weld a new bung on without ruining coating

Ouch!

 

[Lenn Johnson]

Maybe we can just drill the existing bung out and re-thread?

 

[Brock]

Lenn

You could I guess. The OD of stock bung is .750". The new thread is about .200" smaller, so it will be thin material after

 

[Burr600xc]

If you knew someone at a machine shop you could have them make you a collar . Or take a soft .750 bolt drill and tap it out to size you need if you can find the right size thread loctite it into pipe. But a collar with .100 on a side might be to thin to try to tap.

 

[Assaultem]

From what i understand there is either an aftermarket kit available from a vendor, but i don't remember where i read about it.

 

[Lenn Johnson]

I hearing that the new sensor is to big to fit in the older pipe bung. So big that drilling it out would not leave enough material to tap. Looks like I'm having it removed and replaced. Then I'll have to get it re-coated with ceramic. Luckily we have a local guy here that does it in Concord, NH.

 

[Brock]

Pipe makers have had these bungs for the new 18 for awhile.
That's why I said if u drill and tap the original there's less then 0.200" in wall thickness.