melted piston on HCR: Why?

Michelf · Apr 1, 2015

Hello,
Please give a look to these pictures.
I changed end April 2014 the 2 cylinders and 2 pistons of my HCR 800 after I had punched a hole in the heat exchanger, lost the coolant and overheated hard ....My fault….

Now, after 600miles I melted 1 piston. I did a good break in procedure.
Since few years I run always extra oil in the gas grade 90 (say 1/100) to balance the very poor oiling when throttle is in low settings.
My injected oil amount is correct related to daily miles.
The engine died after a short steep climb fallowed by the descent and almost idling to stop near my friend.
Water temperature was around 100°F (have a digital gage now…)
No warning on the dash (egt temp or knock sensor)
Checked the spark plugs at that time : light brown color but not to much (no pictures because I came back over oiling so they are black now)
I poured oil in the cylinder and plenty oil in the gas and did 10miles home 5000rpm mostly down.

What’s wrong????

78A Top bad piston

$C:\Users\Michel\AppData\Local\Temp\msohtmlclip1\01\clip_image002.jpg$

Almost no “wash” : that will be meaning running lean. But EFI is on that side
See bottom of that link
http://www.trackshare.com/forum/showthread.php?t=75715

$C:\Users\Michel\AppData\Local\Temp\msohtmlclip1\01\clip_image004.jpg$

79B bad piston exhaust side
Why the bad piston melted where the little oiling holes are?

$C:\Users\Michel\AppData\Local\Temp\msohtmlclip1\01\clip_image006.jpg$

80C bad piston intake side

$C:\Users\Michel\AppData\Local\Temp\msohtmlclip1\01\clip_image008.jpg$

81D bad piston from below
The black spot tells how hot the piston was running usually: cooking the oil
Here small spot , I believe.

$C:\Users\Michel\AppData\Local\Temp\msohtmlclip1\01\clip_image010.jpg$

85H bad cylinder right from exhaust

$C:\Users\Michel\AppData\Local\Temp\msohtmlclip1\01\clip_image012.jpg$

86I bad cylinder left from exhaust

$C:\Users\Michel\AppData\Local\Temp\msohtmlclip1\01\clip_image014.jpg$

87J bad cylinder intake side
Piston melted where they are no port holes…. Strange!

$C:\Users\Michel\AppData\Local\Temp\msohtmlclip1\01\clip_image016.jpg$

96S bad cylinder after cleaning intake side
I cleaned out the alu deposit on the cylinder and honed it but they are deeps remaining. I was thinking that the hard layer will peel but is appear as eroded or hammered...

$C:\Users\Michel\AppData\Local\Temp\msohtmlclip1\01\clip_image018.jpg$

88K good piston exhaust side
The “blow by” is changing all arround

$C:\Users\Michel\AppData\Local\Temp\msohtmlclip1\01\clip_image020.jpg$

89L good piston intake side

$C:\Users\Michel\AppData\Local\Temp\msohtmlclip1\01\clip_image022.jpg$

93P good piston from below

$C:\Users\Michel\AppData\Local\Temp\msohtmlclip1\01\clip_image024.jpg$

90M good cylinder right of exhaust

$C:\Users\Michel\AppData\Local\Temp\msohtmlclip1\01\clip_image026.jpg$

91N good cylinder intake side

$C:\Users\Michel\AppData\Local\Temp\msohtmlclip1\01\clip_image028.jpg$

92O good cylinder exhaust
Why the scratches on the good cylinder has hight as the top ring?

Easy to repair the top end of the engine but I will be happy to know why it broke down.
I am not always such close from the road to go home!!!!

Please give your comment
Thank you
Michel

Michelf · Apr 1, 2015

Hello,
Please give a look to these pictures.
I changed end April 2014 the 2 cylinders and 2 pistons of my HCR 800 after I had punched a hole in the heat exchanger, lost the coolant and overheated hard ....My fault….

Now, after 600miles I melted 1 piston. I did a good break in procedure.
Since few years I run always extra oil in the gas grade 90 (say 1/100) to balance the very poor oiling when throttle is in low settings.
My injected oil amount is correct related to daily miles.
The engine died after a short steep climb fallowed by the descent and almost idling to stop near my friend.
Water temperature was around 100°F (have a digital gage now…)
No warning on the dash (egt temp or knock sensor)
Checked the spark plugs at that time : light brown color but not to much (no pictures because I came back over oiling so they are black now)
I poured oil in the cylinder and plenty oil in the gas and did 10miles home 5000rpm mostly down.

What’s wrong????

DSC08478A.jpg

78A Top of bad piston

Almost no “wash” : that will be meaning running lean. But EFI is on that side
See bottom of that link
http://www.trackshare.com/forum/showthread.php?t=75715

DSC08479B.jpg

79B bad piston exhaust side
Why the bad piston melted where the little oiling holes are?

DSC08480C.jpg

80C bad piston intake side

DSC08481D.jpg

81D bad piston from below
The black spot tells how hot the piston was running usually: cooking the oil
Here small spot , I believe.

DSC08485H.jpg
85H bad cylinder right from exhaust

DSC08486I.jpg
[FONT=&quot]86I bad cylinder left from exhaust[/FONT]

DSC08487J.jpg
87J bad cylinder intake side
Piston melted where they are no port holes…. Strange!

http://www.snowest.com/forum/attachment.php?attachmentid=252760&stc=1&d=1427945622 DSC08496S.jpg
96S bad cylinder after cleaning intake side
I cleaned out the alu deposit on the cylinder and honed it but they are deeps remaining. I was thinking that the hard layer will peel but is appear as eroded or hammered...

DSC08488K.jpg
88K good piston exhaust side
The “blow by” is changing all arround

DSC08489L.jpg
[FONT=&quot]89L good piston intake side[/FONT]

DSC08493P.jpg
93P good piston from below

DSC08490M.jpg
90M good cylinder right of exhaust

DSC08491N.jpg
91N good cylinder intake side

DSC08492O.jpg
92O good cylinder exhaust
Why the scratches on the good cylinder has hight as the top ring?

Easy to repair the top end of the engine but I will be happy to know why it broke down.
I am not always such close from the road to go home!!!!

Please give your comment
Thank you
Michel

Thunder101 · Apr 1, 2015

Pix didn't work for me

Oil in the fuel tank displaces fuel there for creating a lean condition,more oil= leaner.
500o/5500 is a hot spot

polaris dude · Apr 1, 2015

After consulting with Dam Dave It turns out that your sled is not an arctic cat and it is actually a polaris pro.

At first I didn't believe it either, but Dave made good use of the last 2 hours telling me how much more dependable and sturdy cat engines are so it was an impossibility for one to burn down once let alone twice regardless of driver error.

Michelf · Apr 1, 2015

Thank you Thunder101
I hope you have the pictures now.
Do you think it is looking as lean domage?
If you consider that oil is not burning I will have 1% lest gas in my mixture and be 1% leaner.
I hope that some of the oil is burning and be midway....
I have a adjustable fuel pomp preset at 40 PSI : Do you think that if I go up few PSI it will fix the problem?

kiliki · Apr 2, 2015

if you over heated it hard the first go around and re used the cylinders did you check them for round to see if they are still in spec?

Michelf · Apr 2, 2015

I rebuilded the top end with replated cylinders from a local shop and after market pistons.
So I am just hopping that cylinders have been in specs.
Good question!...
Are the pictures telling you some thing?

kiliki · Apr 2, 2015

it almost looks like a cold seize but the two side are on opposite corners if the cylinder is out of round you will get this. as for the oil displacing the fuel is BS. the pumps come set from 25/1 clear up to mid 40-1 and are not liner to throttle position. also thing to look at are cracked boots or any air leak on that side.
you did warm it up before you got on it hard right?

Thunder101 · Apr 2, 2015

kiliki said:
it almost looks like a cold seize but the two side are on opposite corners if the cylinder is out of round you will get this. as for the oil displacing the fuel is BS. the pumps come set from 25/1 clear up to mid 40-1 and are not liner to throttle position. also thing to look at are cracked boots or any air leak on that side.
you did warm it up before you got on it hard right?

He said he put oil in the fuel tank, at least thats what I read.Tell me how the oil in the tank does not displace fuel.

backcountryislife · Apr 2, 2015

Thunder101 said:
He said he put oil in the fuel tank, at least thats what I read.Tell me how the oil in the tank does not displace fuel.

The level of displacement by adding 100:1 is less than 1%... If you're THAT close that decreasing fuel by 1% put you over the edge, there was another problem prior to that causing a lean condition.

People commonly delete oilers, without adding fuel, and we're then adding about 3%, and the rise in temps is pretty negligible (20-30 is what I've seen)

Thunder101 · Apr 2, 2015

not to mention there is oil burnt on the under side of the crown which means HOT real F ing HOT. =lean midrange on the last seize

The engine died after a short steep climb fallowed by the descent and almost idling to stop near my friend.
Water temperature was around 100°F (have a digital gage now…)
No warning on the dash (egt temp or knock sensor)
Checked the spark plugs at that time : light brown color but not to much (no pictures because I came back over oiling so they are black now)
I poured oil in the cylinder and plenty oil in the gas and did 10miles home 5000rpm mostly down.

You could have had tight clearances but without a doubt the combo of 40psi fuel pressure and oil in the tank probably cased a lean condition but you say no code showed on the short pull up the hill the first time it died so that makes it hard to key board guess the cause.
Next rebuild I would buy cat pistons. and measure the bore.

Anylizer · Apr 2, 2015

after the initial burndown / overheat... was the thermostat replaced??? If not I would bet dollars to doughnuts thats the issue.

After being extremely hot, thermostats cannot function properly, causing this type of seizure. IMO

boondocker97 · Apr 2, 2015

Anylizer said:
after the initial burndown / overheat... was the thermostat replaced??? If not I would bet dollars to doughnuts thats the issue.

After being extremely hot, thermostats cannot function properly, causing this type of seizure. IMO

That was my first thought too. 100 degree water temp is pretty cold and could have started a cold seize on the pull up the hill. Seems to be considerable wear on the "good" piston for only having one season on this top end. Marks evenly around the back side of the matching cylinder at the 2 front corners too. Suggests the entire motor was running tight either from being too cold sometimes or the piston/cylinder clearance was tight to begin with.

I agree mixing 100:1 in the gas isn't going to lean it out enough to make a difference there.

Just noticed the pictures are labeled intake or exhaust side which are the same on these engines haha. We can figure it out though

Michelf · Apr 2, 2015

To Kiliki: I called this morning the shop that supplied me with the cylinders: for them it is a typical 4 corner seizure due to snow intake. So I will go visit my HCR to check out where snow is abble to enter.... tell you later.
No broken boots. I spray WD40 arround the crank shaft seals to check any leaks raising idle. (it will be oily if leaking there?)
Yes engine was warm just very well cooled by 1 foot of fresh powder.
Nice carved turns!

I will have a question: if snow enter the chamber it will cool faster the light piston then the heavier cylinder + coolant.... why is piston squeezing if retracting faster then cylinder???

To Backcountryislife: I have also a Polaris Dragon where I melted 3 pistons under warranty with 6 reflashing ECU always with less power. So I added oil in the gas to keep running. Since after market "Fix Kit" all thing fine in the last 3000 miles and back to full power. But I prefer oiling to much then not enough ! Paranoia ! Or being way to far out from the road on times to take chances!

To Thunder101: Beside the fact that I had a cold seizure the piston are loocking running at the lean side.
I will try to raise my gas pressure from 40PSI to say 44PSI that will increase what injector are delivering at each opening. I will try to find a optic fiber to check the wash. End check if the gas millage is changing (hard to tell, so mutch snow dependent)
I will order this time 2 original cat pistons and go to Millennium Tech for the cylinders (life time waranty)

To Analyser: Forgot to say that at the last rebuilt I changed also: the water impeler
all seals arround
the thermostat
the temp sensor
the knock sensor
added the digital temp sensor in the pipe going to the head (reading not affected by thermostat opening) and I am checking since that gauge closly! !.....

Thank you to all of you

Cat800 · Apr 2, 2015

Where the pistons forged pistons?

Just a suggestion, use stock Arctic Cat Pistons.

green_denali · Apr 2, 2015

burn down

My buddies cat motor burnt up because the water impeller broke, there fore wasn't able to pump coolant through out the motor. His dealer said that had happened on a few others, his was a 2010 800 163. His was less than a month out of warranty but the dealer still was able to warranty the motor.

Michelf · Apr 4, 2015

to Cat800: the piston I put in last year was SPI cast.
Forged piston are may be lasting longer but are less forgiving if you dont warm up the engine well.But I will go this time to original Arctic cat pistons

mbcat · Apr 5, 2015

The oil in your tank constantly hasn't closed off one of the smart valves and starved the injectors? Definitely give it more fuel pressure than 40lbs. That piston definitely expanded faster than that cyl. If your not running the oiler & have your fuel pressure down your also starving it for oil. = 4 corner.

Michelf · Apr 5, 2015

To Mbcat: I am running the oiler and the extra oil in the tank so I am richer in oil than others.
I changed the gas pump because the original one was delivering less then 35 PSI
The BDX Extreme fuel pressure regulator pump is preset to 40 PSI but I can raise it: so I was not turning my pressure down but bealiving in factory settings.
I had years ago a foulded injector limiting 1 cylinder . After cleaning worked fine. So I added a fine particule gas filter in line (after the pump) to avoid to renew that experience.
Will the filter take few PSI away????

ezra · Apr 5, 2015

polaris dude said:
After consulting with Dam Dave It turns out that your sled is not an arctic cat and it is actually a polaris pro.

At first I didn't believe it either, but Dave made good use of the last 2 hours telling me how much more dependable and sturdy cat engines are so it was an impossibility for one to burn down once let alone twice regardless of driver error.

don't talk stupid .if it was a pro the piston would be busted and we would be shown picks of the baseball size hole in the case . :der:

melted piston on HCR: Why?

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