First Time Rebuilding Top End. Advice needed on why it seized...

[Bend Dutchman]

Hey guys,

2018 Axys 800 155 3in

First time rebuilding a top end. Motor only had 1600 miles on it. Anyone have any good advice on why this happened. (Check pic) Is there likely another problem Ineed to look into. i.e. oil pump, thermostat, etc...

Also, considering the amount of debris on top, should i clean the whole motor out before reassembling? And any tips on Piston kit to order, Im leaning towards RK Tek, but they all seem to have benefits.

Thanks for any advice...

 

[Sheetmetalfab]

Hey guys,

2018 Axys 800 155 3in

First time rebuilding a top end. Motor only had 1600 miles on it. Anyone have any good advice on why this happened. (Check pic) Is there likely another problem Ineed to look into. i.e. oil pump, thermostat, etc...

Also, considering the amount of debris on top, should i clean the whole motor out before reassembling? And any tips on Piston kit to order, Im leaning towards RK Tek, but they all seem to have benefits.

Thanks for any advice...

View attachment 364767 View attachment 364768 View attachment 364769

You will need 2015 pro pistons, replated monoblock and oem gaskets.........

Have a local reputable shop do the disassembly / rebuild and check the crank / bearings.

As far as a cause the crank seal might have failed......

Based on your question about checking for debris in the motor you may be setting yourself up for disappointment by doing it on your own........

Stay far away from RK Tek if you want to keep the sled..........

 

[sledhed]

You will need 2015 pro pistons, replated monoblock and oem gaskets.........

<snip>

Why 2015 pistons, were they the best design / durability for the later model 800s? Inquiring minds (with a 2017 800) would like to know.

So the motor definitely should come out completely so it can get torn down the rest of the way for cleaning inspection and new parts as needed... Being first time rebuilding OP's own motor (relative inexperience), with this kind of failure, I would be tempted to just buy a complete rebuilt motor from someone reputable who will stand behind their work, like Indy Specialties, and ride on (not lose a bunch of the season tinkering). I would think if the oil pump had failed the damage would look different than this, and the electric oil pumps *should* throw some kind of error code (recorded in ECU) and put the engine into a limp or shutdown mode of some sort. Just IMHO though... if you want to dive in and figure it all out, feel free, get the crank inspected and fixed as required, oil pump tested?, new seals on crankshaft, new pistons, seals, gaskets, assemble, prime oil and fuel systems etc. and hope you didn't mess anything up since it is all on you then

 

[kmg]

You will need 2015 pro pistons, replated monoblock and oem gaskets.........

Have a local reputable shop do the disassembly / rebuild and check the crank / bearings.

As far as a cause the crank seal might have failed......

Based on your question about checking for debris in the motor you may be setting yourself up for disappointment by doing it on your own........

Stay far away from RK Tek if you want to keep the sled..........

Really? Bad luck with RK tek? I've had good luck with theirs and horrible luck with polaris.. RKtek in 12s and polaris in a 17.. I'm about done with this 17.. was gonna buy RK teks for it

 

[Bend Dutchman]

Cool thanks for responding!

I think I’m gonna drop into a new 850 anyways, so hopefully won’t miss too much of the season.

It’s stuff I’d like to learn anyways, so I’m down to get down into the lower end.

I’ve got the cylinders off, and have some new info.

Check these pics

Any more info anyone has would be amazing. Seen this before? Is it a common place for the cylinders to break?


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[Bend Dutchman]

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[Sheetmetalfab]

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I bet you have a hole in the crankcase also......

Send the whole mess to indydan for the best value. (He can fix that cylinder)

Piston knife edged from detonation and or lean condition.

(Maybe lost a ring retainer) caused by detonation.

Piston skirt broke first, then that broke the cylinder skirt.

 

[Sheetmetalfab]

Why 2015 pistons, were they the best design / durability for the later model 800s? Inquiring minds (with a 2017 800) would like to know.

So the motor definitely should come out completely so it can get torn down the rest of the way for cleaning inspection and new parts as needed... Being first time rebuilding OP's own motor (relative inexperience), with this kind of failure, I would be tempted to just buy a complete rebuilt motor from someone reputable who will stand behind their work, like Indy Specialties, and ride on (not lose a bunch of the season tinkering). I would think if the oil pump had failed the damage would look different than this, and the electric oil pumps *should* throw some kind of error code (recorded in ECU) and put the engine into a limp or shutdown mode of some sort. Just IMHO though... if you want to dive in and figure it all out, feel free, get the crank inspected and fixed as required, oil pump tested?, new seals on crankshaft, new pistons, seals, gaskets, assemble, prime oil and fuel systems etc. and hope you didn't mess anything up since it is all on you then

2015 pro pistons do not lose ring retaining pins like 16-20 800 pistons do. (Under mild detonation)

They are cheaper to boot.

Simply the toughest piston available.

 

[Sheetmetalfab]

Really? Bad luck with RK tek? I've had good luck with theirs and horrible luck with polaris.. RKtek in 12s and polaris in a 17.. I'm about done with this 17.. was gonna buy RK teks for it

My Personal experience was terrible.

Stick with your purchase justification........

I like shops that stand behind their work.

 

[kmg]

My Personal experience was terrible.

Stick with your purchase justification........

I like shops that stand behind their work.

Fair enough. I thought maybe a more in depth reason then a bad experience.

As far as shops that stand behind their work... I'm the shop. So it don't matter who's piston if it's a shop error I'm to blame.

 

[IcutMetl]

Damage like that to the pistons and there’s a question weather or not to clean out the bottom end? I agree with those that have suggested having it gone by a professional or to replace it with a complete engine; don’t pass that problem off to the next guy.

 

[mtncat1]

you will have to split the cases on that to make sure you didn't crack the case , if it is cracked it can be welded with no adverse effects

 

[sledhed]

you will have to split the cases on that to make sure you didn't crack the case , if it is cracked it can be welded with no adverse effects

Mtncat1: If you get it welded, do you have to line-bore it again?

OP:
At this point, if the case is cracked (probably, but cases have to be split anyway), the crank will be questionable (bearings, runout, rods), the cylinder block is obviously in tough shape, and who knows what else you will find in there... you are going to have to farm out a bunch of that work unless you are able to properly do all of that work... I'd take pics and slap it back together as a core (if someone will take it as a core) and find a reputable builder to exchange it out. Or look for a complete used engine to drop in and send the whole sled down the road and jump onto an 850 if thats what you want.

 

[mtncat1]

Mtncat1: If you get it welded, do you have to line-bore it again?

OP:
At this point, if the case is cracked (probably, but cases have to be split anyway), the crank will be questionable (bearings, runout, rods), the cylinder block is obviously in tough shape, and who knows what else you will find in there... you are going to have to farm out a bunch of that work unless you are able to properly do all of that work... I'd take pics and slap it back together as a core (if someone will take it as a core) and find a reputable builder to exchange it out. Or look for a complete used engine to drop in and send the whole sled down the road and jump onto an 850 if thats what you want.

i never have had to line bore one ,i've had several welded and never been charged more than a 100 bucks , it is very tight clearance in the bottom of the case so you have to clean up the weld inside the case with a die grinder

 

[Bend Dutchman]

Caved and bought an Indy Long Rod motor. Pretty excited about it after reading tons of reviews.

I installed an SLP pipe and can on this at the beginning of the season. Is there any reason that would have been the cause of the piston failure?


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[Bend Dutchman]

One more q also...

I took out the E-EVES unit, it’s still attached to cable on both ends. After cleaning, is it necessary/ok to use some VES oil as lubricant to re install in new motor?


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[Sheetmetalfab]

Caved and bought an Indy Long Rod motor. Pretty excited about it after reading tons of reviews.

I installed an SLP pipe and can on this at the beginning of the season. Is there any reason that would have been the cause of the piston failure?


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My brothers 2018 sled ran great with that pipe can combo.

If you are low level detonating due to poor fuel it could cause the failure.

Non ethanol/ fresh 92 octane gas is needed with the slp pipe.

If you are suspicious of your fuel you can run in ethanol mode full time.

The SLP resistors are very low quality and usually cause run ability issues.

 

[sledhed]

My brothers 2018 sled ran great with that pipe can combo.

If you are low level detonating due to poor fuel it could cause the failure.

Non ethanol/ fresh 92 octane gas is needed with the slp pipe.

If you are suspicious of your fuel you can run in ethanol mode full time.

The SLP resistors are very low quality and usually cause run ability issues.

Running an SLP pipe setup in my 17, run 91 pump non-ethanol, usually 5K and up, no issues whatsoever, never a DET, always in non-ethanol mode, no resistor on exhaust sensor... I really doubt that would have cause it unless maybe running 87 octane ethanol on non-ethanol mode, or running low elevation without the resistor...

 

[Bend Dutchman]

I pretty much always run 91 or 92 non eth. I did put maybe a gallon of premium in it (was the only option) one time recently.

Im just concerned that it was only at 1600 miles and it seized. Don’t want to put this new Indy motor in and have it do the same.

Do you guys think it’s worth putting the new motor in, and taking it to the Polaris shop and just having them run thru it? Is it something that a Digital Wrench could determine is running smooth?


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[Sheetmetalfab]

I pretty much always run 91 or 92 non eth. I did put maybe a gallon of premium in it (was the only option) one time recently.

Im just concerned that it was only at 1600 miles and it seized. Don’t want to put this new Indy motor in and have it do the same.

Do you guys think it’s worth putting the new motor in, and taking it to the Polaris shop and just having them run thru it? Is it something that a Digital Wrench could determine is running smooth?


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The time to check is during disassembly.

Ring locator pin out?
Leaky crank seal (pressure test)
Test spray the injectors
Snow/ water ingestion?
Lack of proper warm up?
Bad wrist pin bearing send shrapnel through the motor?

At this point?
Maybe indydan can analyze your core?