Top end - replace 1 piston and cylinder only? - Page 2 - Snowmobile Forum: Your #1 Snowmobile Forum

Renagade · 05-02-2012, 10:47 PM

Quote:

Originally Posted by kccats

So have you heard thats its time for an upgrade?

only at cat dealer!! hahahahaha

prolly at every dealer, then insult you
with a terrible trade in price!!!!!

**kccats** · 05-03-2012, 05:26 AM

We heard that at all the Stealers Dennis and I went too!

Renagade · 05-03-2012, 07:23 AM

Quote:

Originally Posted by kccats

We heard that at all the Stealers Dennis and I went too!

all the stealerships will be saying "time for an upgrade".

but the cat boys are wanting an upgrade for all those
bent tunnels & blown belts on the 12 turbo!!!

id still repl both jugs for mind insurance!!!

losian79 · 05-03-2012, 01:32 PM

Thanks for the feedback. The dealer also told me it wasn't getting enough oil, so they turned the oil up. Could that cause burn down in 1 cylinder? If you are sitting on the snowmobile, the one on the left side burned.

They did give me the cylinders and pistons. I've attached 2 pictures of the bad piston and one of the good piston. Also a picture of the cylinders and pistons together.

One of the reason I had both cylinders done is because Polaris updates the pistons. I didn't want 2 different pistons.

**kccats** · 05-03-2012, 02:02 PM

I think looking at that I would atleast replace that side seal too!

**RJ Gleason** · 05-03-2012, 03:15 PM

How does the top of that scored piston look?

losian79 · 05-04-2012, 04:44 PM

kccats - those are the old parts. When you refer to side seal are you talking about something you see, or something connected to what you see that is still on the sled?

RJ Gleason - piston tops pictures uploaded. The tops look pretty similar to each other. The burned down on is on the left. The major difference was on the sides with the scoring and the blow-through next just above the rings (visible in first set of pics).

**kccats** · 05-05-2012, 05:14 AM

Piston wash don't look bad! The seal is on the end of the crank. I wonder if this shouldn't be covered under the piston recall? The top of the pistons are not gray or too lean looking! If anything maybe a cold sease?

**RJ Gleason** · 05-05-2012, 08:14 AM

Definitely not a lean condition, lack of oil is the correct diagnosis as to why the engine failed.

yamadad4 · 05-05-2012, 09:01 AM

cant tell the orientation from the pictures but is the scoring on the intake side of the piston or the exhaust side, or both?

is there any oil presence on the inside of the piston under the crown and above where the wrist pin is located?

the scoring almost resembles snow or water ingestion.

losian79 · 05-06-2012, 08:07 PM

kccats- Thanks for this mention of "wash". Previously I didn't know you could identify possible issue with lean/rich by looking at the pistons. Which piston recall do you refer to? This sled is a 2009. My understanding is that its been out of warranty for 2 years. As for a cold sieze, the sled was good and warm. I had traveled about 10 miles when this happened. The snow was just starting to get deeper (~3 ft) and I had just opened it up on a straightway. I was driving on fireroads so the was only a slight incline.

RJ - is your diagnosis on based on the looking at the pistons? Can you explain a little more?

Yamada - the scoring is on both sides. There is oil under the crown on both pistons. Why do you ask? How does the scoring indicate water/snow ingestion? How is that possible ? A bad seal?

**kccats** · 05-06-2012, 08:35 PM

Quote:

Originally Posted by losian79

We had 87 octane in it (fine according the manual). But they dealership left the wire plugged in that requires 91 octane with no ethanol. That was most certainly the problem. This wire is not described in the manual, but Polaris had some print out that they had posted on their door that clearly stated this wire needed to be unplugged.

Polaris also updated the pistons since their recall on this machine so getting both done ensured I had the same pistons.

This what you said!
If you injested snow it would have possibly hydrolocked?

losian79 · 05-06-2012, 08:44 PM

The recall happened before I bought the sled. They have come out with new pistons since the pistons were updated as part of the recall. To my knowledge they did not issue another recall.

I don't know much about hydrolocking but a quick google of it shows bent connecting rods. Pretty sure we didn't have those. I guess with smaller amounts of water there would be less of a catastrophic failure, but I don't know if that would cause the scoring?

I guess I'm interested in the fact that besides the scoring, the edges of the bad piston are worn off. Like something blew by the rings and ate the corners off. I haven't seen that anywhere else and haven't heard an explanation of why that would happen.
Any ideas?

**RJ Gleason** · 05-06-2012, 09:56 PM

Hydro lock, no!
Water/snow injestion, possible.
But, if it did that, both pistons would show damage from leaning out.

I'm sticking with lack of oil for that cylinder.

losian79 · 05-06-2012, 10:36 PM

Quote:

Originally Posted by RJ Gleason

I'm sticking with lack of oil for that cylinder.

Does something you see point at lack of oil or is this what you figure from the explanation of possibilities?

**RJ Gleason** · 05-06-2012, 10:42 PM

See explanation in the above post.

Side scoring and edge deformation with clean top are a symptom of lack of oil.
Also look at the bearing ends of the rod, particularly the crank end and look for any "bluing" of the metal. This will also point to lack of oil.

**kccats** · 05-07-2012, 06:45 AM

My question is Why was there a recall on the pistons? Was yours previously done?

yamadad4 · 05-07-2012, 07:32 AM

the fact there was oil present on the underside of the piston could lead one to believe your oil system was working properly. only an assumption. the pistons can tell more to the story, not seeing enough in the pictures. scuffing is usually seen as more concentrated on the intake side as well near the transfer port areas on the sides, but it can also go full around, depending on how long it ran and how much water.

when snow dust or water is ingested into the cylinders, the oil is "washed off", so to speak, and can wash the carbon of the piston crown. the cooked piston with the ashen gray color is indicative of water ingestion, similar to lack of oil in appearance, but a lack of oil usually shows more damage.

water/snow dust can be ingested through ill fitting boots between the throttle body and the airbox or even an issue between the throttle body and the cylinders. polaris is notorious for ill fitting boots and poor hose clamps. not a brand bash, just an observation from personal experience. hence only one cylinder having the issue.

you could even consider the head gasket or the o ring as a probable cause. one could assume an oiling issue would have shown on both pistons, unless there was an obstruction or issue with the oil lines to the bad piston.

3' of fresh loose snow, or riding atop packed snow?

losian79 · 05-12-2012, 03:10 PM

Quote:

Originally Posted by kccats

My question is Why was there a recall on the pistons? Was yours previously done?

There was recall and my pistons were updated. There since has been an update, but as I understand it it was not a recall.

losian79 · 05-12-2012, 03:14 PM

Finally took the pistons and cylinders to the local shop. Mechanic there says lack of oil. There didn't seem to be any question in his mind. Guess the dealership where i got the sled neglected to tell me that since they sold me the sled either with a clogged oil line or pumping way to little oil.