Just a little FYI on the Polaris CFI Engine and surrounding rumors

[Chrisco]

Ryeser has a dragon with a pms piston kit.

 

[CrankShop910]

So Kelsey, what does it seem that the turbo dragon and pro motors last longer then stockers. You would think with the add heat on the piston it would fail faster then a stocker, but I know of three dragon engines, that have been turbo from new and there still on the 08 update pistons and are still going strong.

 

[gmustangt]

Kelsey do the direct replacement pistons change port timing, case volume, or compression in any way shape or form?

 

[RK Tek]

So Kelsey, what does it seem that the turbo dragon and pro motors last longer then stockers. You would think with the add heat on the piston it would fail faster then a stocker, but I know of three dragon engines, that have been turbo from new and there still on the 08 update pistons and are still going strong.

Great question

Turbos have more raw unburnt fuel in the crankcase fuel cools.. Also case pressures are higher in a turbo... also turbos are
never run WOT constantly, like N/A engine..

Turbos put more stress on the crank train but CAN run provide more "cushion" due to the excess fuel that is always present .

But, I think mainly it is simply because they are not held WOT for as long..

Other question.. No, my Direct Replacement pistons do not alter any compression ratio. case volume is changed slightly

 

[lilduke]

Great question

Turbos have more raw unburnt fuel in the crankcase fuel cools.. Also case pressures are higher in a turbo... also turbos are
never run WOT constantly, like N/A engine..

Turbos put more stress on the crank train but CAN run provide more "cushion" due to the excess fuel that is always present .

But, I think mainly it is simply because they are not held WOT for as long..

Other question.. No, my Direct Replacement pistons do not alter any compression ratio. case volume is changed slightly

Im thinkin so too. I don't think it would be a good plan to hold the race gas turbo dragon wide open for 5or10minutes straight...lol

 

[RK Tek]

Is there a benefit to installing a bypass on this motor and running it cooler? I was noticing a huge power loss last march in wet heavy snow and when I would look at the temp it was 140 plus but would drop as soon as I would let off the throttle and then the power would be back until the next temp spike.

If you are seeing anything over 140 then you should do something to lower that temp.. We usually always run at about 126....
I would just pull the T Stat and that should do it.. But I have heard people having some luck with the Ski doo t stat set up.. We use all stock and have no issues..

We actually played with this quite a bit last season.. We rigged up a temp fooler and made it think that it was hotter than it was.. We noticed not power loss (ECM pull back) until 150 degrees.. We were trying to find the high and low limits to see when the computer started to adjust... Again.. High end was about 150.. but the cooler the better IMO

 

[Chrisco]

My kits came in today Kelsey.

 

[sketch96]

Do the kit! Dont wait to see if you have a good motor or not. The skirt broke on my piston and dropped into the bottom and that was all she wrote. Complete new motor on warranty from polaris. And the wait to get one was over a month. Do the kit and hopefully you will solve any issues before you have a bigger problem
As for what Kelsey said about polaris cylinders all being in spec and that a manufacturer as big as polaris not seeing, or ignoring the machining or manufacturing process of their cylinders.....I would tend to agree on that, BUT how could they continually overlook the issue of all the bad pistons they are putting into these "in spec" cylinders!

Makes me wonder! Really sucks to spend that kind of money on a new sled only to have to tear the motor down and replace the pistons to have some piece of mind in the mountains.......not only that but if you do this you void the factory waranty!!!! So if you still by chance have an issue you are on the hook for the bill.

Not where I want to be anymore. When they develop a motor that puts out at least 160hp with reliability so a guy can keep his warranty and have piece of mind I will not be back on a polaris. Again as I said before......after 20 yrs on a polaris......I love the chassis and clutching....hate the underpowered unreliable motor!

 

[RK Tek]

Chris.. Glad your parts showed..


Sketch... I am glad you agree... The simple truth is that Polaris "Cheaped" on the pistons to save money.. So, the metalurgy is simply not correct and the pistons do not hold their shape.. Couple this with the lack of cylinder lower support and you have the recipe for a piston that will have issues..
Polaris, just this year got back to a FUJI crank after 5 years of struggling with the MAPE crank on the Dragons and the Pros.. So, hopefully, this FUJI will show more longevity.

Speaking of Cranks.. Tha reminds me of yet another "rumor" that some are trying to force down people's throats about this engine

So, We will add another... How's that?

5) The 2013 Pro Crank is "OFFSET" in the cylinder with respect to centerline... 100% TOTALLY FALSE!!
yet another sales gimmick to try and sell crank parts..
ALL the Ski Doo, CAT, and Polaris cranks are 100% on centerline with the piston pin.. There is ZERO Offset! This can be and has been proven very easy to prove..

I even had to make a video (and a piss poor one at that) to prove this to the resident forum crank expert (who thinks that measuring form the reed gasket to the case tells you anything about the crank pinning.. WOW) anyway.. the piston and crank have no offset... All Polaris did is change from Mape to FUJI for manufacturing.

 

[trench]

Picked up my kit today, parts look top notch thanks Kelsey.

 

[tavis43]

so who made the crank in the 13 models?

 

[rmscustom]

so who made the crank in the 13 models?

Fuji for 13 and half Fuji half mape for 12 I believe.

 

[Braddock54]

Thanks RK. Good info for us poo folk.

 

[RK Tek]

Fuji for 13 and half Fuji half mape for 12 I believe.

Not 100 correct

Polaris installed a very ,imited number of 2012 engines with the FUJI crank.. ONLY THEY knew which ones had them.. I suspect they did this to monitor/test.. let us test them like usual .. But most 2012 engines still had the MAPE crank..

 

[rmscustom]

Kelsey,
Pulled my 13 apart tonight. 1350 hard mountain miles and the rings are flaked bad on the intake side. What causes that?

 

[Lococoin]

Question for you Kelsey.

Didn't polaris increase the cylinder skirt thickness in 2013? Why would spend the money to retool to do this if the issue is with the piston. Wouldn't it have been easier and cheaper for them to just build a higher quality piston?

 

[Ol' Sarge]

Question for you Kelsey.

Didn't polaris increase the cylinder skirt thickness in 2013? Why would spend the money to retool to do this if the issue is with the piston. Wouldn't it have been easier and cheaper for them to just build a higher quality piston?

That's a good question. Here's another one. If there is no offset in the '13 engines then why are the '13 case halves described in the parts manual as "offset" and not interchangeable with previous engines?
I would caution anyone that before they endorse Kelsey's theory on this that they also have a look at what Indy Dan has to say and come to your conclusions after that. He also created a video regarding offset. Call him or do a search on SW. It would be nice if Kelsey could just hawk his goods the old fashioned way, by promoting it's benefits, instead of slamming his competition in sled forums.

 

[RK Tek]

Kelsey,
Pulled my 13 apart tonight. 1350 hard mountain miles and the rings are flaked bad on the intake side. What causes that?

Very simple cause.. POOR RINGS!! Again.. very cheaply made pistons.

Another contributor is a loose piston.. This will allow the piston rings to become unparallel with the bore so you have more directed pressure on the rings surface vs. an even pressure when the rings are flush with the bore..

Great question!

 

[RK Tek]

Question for you Kelsey.

Didn't polaris increase the cylinder skirt thickness in 2013? Why would spend the money to retool to do this if the issue is with the piston. Wouldn't it have been easier and cheaper for them to just build a higher quality piston?

Yes, they did thicken up the lower cylinder skirt..

Why do this vs. a new piston?

Here are my thoughts and we are a mold making shop. so we totally understand tooling and mold design.

OK, making a new piston requires time and rigorous testing.. This takes time and money. from a business standpoint.. this money you will NOT re-coop.

Changing a mold to thicken a skirt is VERY simple and can be done to the EXISTING mold.. So, it is NOT a whole new design, re-tool and manufacture but a SIMPLE alteration to the existing mold.. Very inexpensive to do.. This is called a "re-work" in the tool and die industry.

Also, the concept is SO SIMPLE that it requires no testing... Just modify the existing and you KNOW it will do what you suspect because it is a non moving part.

This is UNLIKE their 2013 drive-shaft change where they made a change to a moving part, did not test it, and had major failure (yes, we fixed that issue for Polaris as well). So, anytime you make a change to a non moving part, like a cylinder, you can have more confidence that the change will be effective, especially one that is this simple!


So, I would suspect Polaris did this because of the cost is MUCH cheaper , it is/was VERY easy to implement and now the skirts of the cylinder will not fracture..

Another great question.

 

[lilduke]

That's a good question. Here's another one. If there is no offset in the '13 engines then why are the '13 case halves described in the parts manual as "offset" and not interchangeable with previous engines?
I would caution anyone that before they endorse Kelsey's theory on this that they also have a look at what Indy Dan has to say and come to your conclusions after that. He also created a video regarding offset. Call him or do a search on SW. It would be nice if Kelsey could just hawk his goods the old fashioned way, by promoting it's benefits, instead of slamming his competition in sled forums.

What about this question? don't think its a good one?