11'-12' Engine Issue

[Leftys]

Thought I'd start a new thread on this issue and see if much has changed with anyone else's original vote on the engine poll.

First off I have a 12'. I originally had no issues with my engine with 1100 miles on it. That is where my vote went on the original post.

On what turned out to be my last ride of the season (not intended to be the last) with 2100 miles on my engine the Mag side Cylinder Intake Skirt broke off and went through the bottom case and broke the Reed area of the upper case. I was traveling down the trail just about to the good stuff when pow it went. Right around the 6400 RPM range when it happened. My primary riding is trees, so on and off the throttle often with wide open pulls under high load. When on the trail very seldom go over 7000 RPM. Over the trail racer stuff and the belts last much longer. I have turned my Oil Pump Up as far as I could without getting the top of the threads on the set screw into the nut. Have never added oil to the fuel tank which IMO does nothing for the bottom end and very little for piston lubrication. No benefit from doing so for the engine problem I had, again IMO. I always had a little worry in me wondering when my engine would fail. Thank the Lord I was in an easy spot to tow out. Just wanted to give an honest review on what I experienced that was not in a poll. I now have a 13' short block in my sled. We'll see it rips next year. Till then....

 

[KAWGRN]

At 1100 miles I installed the mkt kit now have 3000 probably ready for new pistons this season ,,,but on stock pistons I think 1999 miles is the limit for me!

 

[knifedge]

--do not use oem pistons either

 

[snowman80]

I had 1500 miles on my stock '11 with no problems for me. Traded her for a '13 though.

 

[wfieldin]

11- 12 engine failure

My magic number was right at 1800, close to end of season and was holding off on top end....BAD CHOICE...don't wait

 

[dttrusko]

Just over 3k miles on my 11' with no major issues.. Replaced the top end beginning of the season last year at ~2k with oem pistons and plan on doing the same this fall.

Are people replacing cylinders when doing the top end even if they look good? Hearing about all the broken skirts makes me a little nervous.

 

[rydningen]

Just over 3k miles on my 11' with no major issues.. Replaced the top end beginning of the season last year at ~2k with oem pistons and plan on doing the same this fall.

Are people replacing cylinders when doing the top end even if they look good? Hearing about all the broken skirts makes me a little nervous.

Cylinders are probably fully useable, the problem is that the stock pistons have tolerances pretty much out of spec when new. The cylinder/piston clearance that is, this also increases as the mileage goes up.

Piston starts to rock excessively in the cylinder and eventually either knocks off the piston skirt, cylinder skirt, or both.

I changed out my pistons with the RKT replacement pistons, not taking the chance with the OEM pistons. Too many reports of them failing prematurely and being out of specifications after low mileage.

 

[suitcase]

JMO, but most all Mod motor builder recommend to have the top end done at about 1500 miles. Does the modern snowmobile motor need the same guide lines? In the 90's I really never thought about it tell 3000, and I never had any issues knock on wood. Just a thought!!

 

[boondocker163]

ive got 700 miles on my 12, i bought it with 500 and the end of the year. No problems so far but thats not saying much.. I dunno what i am going to do.. debating doing some wisco pistons or kelseys pistons with an slp stage 3 kit...

 

[yzviper366]

my girlfriend has a 2011 RMK 800 with 2500 miles on the OEM pistons everything is holding up so far but reading this makes me nervous what are people doing to make them better can I just buy replacement pistons and will it be good? Or do I needother things as well?who makes stronger pistons for the stock bore? if I buy the stronger pistons do I need different cylinders as well or will the stock cylinders be fine? Also when I change the Pistons do I need to have the cylinders honed or can I just drop the new ones in?

 

[wfieldin]

Several aftermarket options with lowest cost probably being rktek drop in kit that is pistons only for under $400, PMS mountain tek fix kit for just under $600 all the way up to an Indy Dan Long Rod for $2500. All have followers do your research and go with what/who you are comfortable with. I'm sure there are others out there as well.

 

[Rev Kev]

My 2011 has 2354 miles on it, no major problems, and completely stock. I will be putting a fresh top end this Summer, using Indy Dan's Modded cylinders and Pistons.

 

[LoudHandle]

The pistons have never been the problem, It is the lack of quality control on the mono-block cylinder, and you need to use the term "cylinder" loosely with stock Polaris mono blocks. They can't / don't even meet their own published specifications. The stock mono-block cylinder is at best a Hyperboloid or hour glass shape. So throwing an aftermarket piston in a stock mono-block cylinder is still no better than leaving it alone. To really fix things, IMO; the mono-block cylinder needs to be stripped and re-plated and re-honed to the proper specifications. IMO the only one to do this is Indy Dan, I also prefer the Long Rod option in addition to just the top end, and eliminate all the engineering errors in the design as well as all the quality control issues.

Again the reason the piston to cylinder clearance does not meet the Polaris published specification is the out of spec. mono-block cylinder not the stock pistons. If you are just buying a drop in piston kit without measuring your cylinder you are continuing to play Russian Roulette and will most likely ultimately pay the price for trying to be thrifty. You may get lucky and you may not, same as leaving it stock.

 

[4Z]

Also, history has shown that not all mono blocks are not created equal. Expansion and contraction from heat is greater/less depending on the area and the amount of material in that area. Don't know this for sure, but I would be willing to bet there are some goofy expansion and contraction issues going on. Then couple that with inconsistent cooling system.

.02

 

[rydningen]

Soo, in a nutshell.

The polaris engine is crappy and undependable no matter what you do to it....at least with the monoblock?

I guess the only thing to do is to get some BB separated cylinders

 

[LoudHandle]

Soo, in a nutshell.

The polaris engine is crappy and undependable no matter what you do to it....at least with the monoblock?............

That statement is a bit of a stretch, like anything that is mass produced it benefits greatly from some skilled blueprinting and actually getting it into specifications. There is nothing wrong with the mono-block once it is put into spec. Additionally Indy Dan will warranty his rework of your "crappy and undependable Polaris engine" for three years, which says a lot when Polaris fights you every step of the way with their "warranty and extended service contracts". I for one will not pay for a "Polaris warranty or extended service contract" because it is not worth the paper it is printed on. I instead pull the engine and send it to Indy Dan, get it long rodded and be done with it. The decision is yours.

 

[yzviper366]

it is quite surprising how many different opinions there are on this engineI have now heard three different stories one from RKT, one from a engine builder in my town and now one from youso it's pretty obvious to me that this issue with the 2011 and 2012 engine is still yet to be solved.

 

[rydningen]

That statement is a bit of a stretch, like anything that is mass produced it benefits greatly from some skilled blueprinting and actually getting it into specifications. There is nothing wrong with the mono-block once it is put into spec. Additionally Indy Dan will warranty his rework of your "crappy and undependable Polaris engine" for three years, which says a lot when Polaris fights you every step of the way with their "warranty and extended service contracts". I for one will not pay for a "Polaris warranty or extended service contract" because it is not worth the paper it is printed on. I instead pull the engine and send it to Indy Dan, get it long rodded and be done with it. The decision is yours.

Well, I know it was and that was what I intended.

I changed out my polaris pistons with a set from rktek at 2000miles, compression was low on both sides...pistons looked ok but I did not measure them. I guess the rings were shot, and I would expect them to be after that mileage.

I have a long rod from Dan ready to go in my 11, sending the whole engine to him was not an option because shipping would be allmost as much as he charges for the top notch work he does. I fully understand why people chose to get the full package from him.

As far as the cylinders being out of spec, I did not get the cylinders from Dan because I want to BB in the future, and I do not think my engine will grenade with the setup I will be running until then. I never have had problems with my polaris engines in the past either. (Hope I did not jinx myself there)

 

[LoudHandle]

I know full well what shipping costs, as I am in Alaska.
But it is worth it! By the way if you stay under 70#'s the good old USPS kicks the others Azz, about $1 a pound, so pretty economical at that point. The last four engines I have bought have been stateside so I only have to pay the big fee once. Send the engine to Dan in pieces. Way cheaper.

 

[RKT]

I have measured at least 100 cylinders of the Polaris 800 and have not seen 1 where the cylinder was out of spec in any way..
The problem is not the cylinder, however, there are "other" issues with this cylinder design..

The problem is the piston design and is easily fixed with a "correct" piston.

As for a long rod and choked off air flow in the transfer ducts... Please get back with us on that after you "compare".. I think you will be very surprised at the top end "performance".