06 REV 800 Motor Fail

[yotaman1290]

Well, my motor decided to blow up today.
Here is a little history on it.
Bought the sled a few weeks ago, rebuilt the top end and re packed the crank bearings. Rode it around the house for like 2 hours (ran perfect).
I took it up in the mountains this morning and only made it like 5 miles up the trail when the pto side rod decided to snap in half.
Now this just seems weird to me that a rod would just break.
I was taking the motor easy to try and break it in and was just cruising at like 40 mph when BOOM. The rod broke and took out both cases.

TOOK THE MOTOR APART!!
Here are some pictures of the motor after i took it apart.
Keep in mind the motor has only about 2 hours of run time and all has been with a 50:1 premix in gas.
Also, i was going down the trail on not on the gas when it blew.

I took every step to ensure the motor to run good:
-Used mineral XPS 2 stroke oil
-Bled oil pump and lines
-Held oil pump open on initial start until it smoked like crazy (did it like 3 times)
-Had no lights, engine codes and engine ran wonderful
-No leaks of any kind
-Started two pulls cold with choke on and one pull once warm
-Always warmed it up before i rode it (never even got a chance to ride it hard or open her up real good)

So, with that being said, i believe this motor blow is due to piston failure. If you look at the piston that is still good, the coating is all work off and looks like it is just disintegrating!

So by reading what has been done, here is what i think happened:
1- the piston coating wore off and now the piston is not protected.
2- the skirt on piston shattered and sent metal everywhere.
3- the metal from the piston jammed the piston which in turn broke the rod.
4- the existing part of the rod on the crank spun around and absolutely demolished the cases and cylinder.
5- you can see the rod is bent and the only way is could bend is if the top end failed.

BOTH rod bearings on the crank and needle bearing on piston are free and spin great.
All crank bearings are good

How would you guys go about trying to deal with SPI about this?
Clearly it is not my fault and the pistons are the issue. I am now out the time and money for the original build and now i have no motor!!!
I need something from SPI!


Here is a link to my Photobucket where all the pictures are:
Motor Pictures

Here is a video of the bearings:
http://www.youtube.com/watch?v=pb0BlztvJwg

 

[skibreeze]

The coatings on the pistons are just for break in, they will wear off. Rods do fail also, just like anything else.

 

[yotaman1290]

The coatings on the pistons are just for break in, they will wear off. Rods do fail also, just like anything else.

The coating is supposed to increase heat transfer, reduce friction and help reduce cold siezures.
Also, a rod is not going to break out of the blue especially with only 1800 miles. The top end had to seize for the rod to bend and break...

 

[reevs]

800 rev 2006

Sounds like you have my luck! Last weekend my 2006 rev800 144 turned 2000 miles and at 2014 miles BAM!!!! Opened clutch side panel and saw a wrist pin and upper half of connecting laying in bellypan. what a sight- best snow so far this year and now i am looking for a 800 ho without a core, because my lower crankcase is missing a big piece!!!!!!!!!

 

[Vailguy]

So frustrating...There you are, packed the bearings, doing the slow break in, thinking you are a good boy scout. Then bam, at times like these, I wish I was Amish.

 

[zxsummitrider01]

that sucks! Have to say though even if you did do everything right i think you are going to have a hard time getting anything out of spi. No way to prove that the failure was their fault even though it is extremly unlikly that the rod would just have a sudden failure like that. you shouldn't have to but did you measure the pistons and or the cylinder's b4 installation to ensure clearences were in spec? check ring end gap? new wrist pins and bearings? Ive had terrible luck with spi pistons, specifically the size of them, terrible qc. tried to throw a set in a zx 700 one time, had the cylinder's measured, honed and they were in spec, put the spi pistons in w/o measuring, they were so small didnt even have enough compression to start, took them out measured them and they were WAY small. had them send me another set thinking it was a fluke, measured them b4 install this time and the second set was too tight to run. i would guess thats what happened to your's. the coating did wear off but a piston should run w/out it. im guessing they were too tight and when they got a good heat soak in them being nice going down the trail (constant temp) they expanded too much and grabbed the cylinder. no matter how ya look at it it sucks!
Good luck sorry to hear of your missfortune

 

[summit ate]

I had something simular afew yrs ago, stay away from spi pistons and use stock skidoo, cost more ,but wont do that

 

[yotaman1290]

that sucks! Have to say though even if you did do everything right i think you are going to have a hard time getting anything out of spi. No way to prove that the failure was their fault even though it is extremly unlikly that the rod would just have a sudden failure like that. you shouldn't have to but did you measure the pistons and or the cylinder's b4 installation to ensure clearences were in spec? check ring end gap? new wrist pins and bearings? Ive had terrible luck with spi pistons, specifically the size of them, terrible qc. tried to throw a set in a zx 700 one time, had the cylinder's measured, honed and they were in spec, put the spi pistons in w/o measuring, they were so small didnt even have enough compression to start, took them out measured them and they were WAY small. had them send me another set thinking it was a fluke, measured them b4 install this time and the second set was too tight to run. i would guess thats what happened to your's. the coating did wear off but a piston should run w/out it. im guessing they were too tight and when they got a good heat soak in them being nice going down the trail (constant temp) they expanded too much and grabbed the cylinder. no matter how ya look at it it sucks!
Good luck sorry to hear of your missfortune

Thanks for the response! The ring end gap is .016" and piston skirt to cylinder clearance is .005". I did install new wrist pin bearings also.

If anyone has parts for sale, please let me know. I wanna get this thing back on the snow!!!

 

[redneckj]

Why does the rod look like it is rusted real bad? Also, I have never heard, "the coating on the pistons is designed to wear off, it is there for break in". This is what i am use to seeing as far as piston coatings.
http://www.swaintech.com/store.asp?pid=10297

 

[skibreeze]

Why does the rod look like it is rusted real bad? Also, I have never heard, "the coating on the pistons is designed to wear off, it is there for break in". This is what i am use to seeing as far as piston coatings.
http://www.swaintech.com/store.asp?pid=10297

Read your own link:

Do not mistake Swain’s coatings with the basic break in coatings some factory pistons are treated with or a simple plating or anodizing process done to a piston.

 

[SkiCat]

06 rev 800 motor fail

When you rebuilt the motor did you replace the oil check valves in the motor case from the oil pump or even check them. I have two 06 800 revs and both have had new motors after oil failures and found bad oil check valves. The first skidoo blew at 425 miles and the second at 2400 miles.

 

[d&mraceengines]

i do see in the piston picks what looks like smoe meatal moving or scuffing. the coating on thoose pistons is more for breakin than any thing it wears off
quickly high end piston amnufactures like je dont coat there pistons they say they dont need coated if you are gonna dyno your engine coating only for break in . if there was meatal moving or scuffing which it looks like there was that is from exsesive heat high egts and alot of sleds go lean on the slow cruising like that never recomend that on a 2 stroke you always wanna be working the throttle to keep enough fuel in the engine and not have egt temps to spike have seen more than one engine blown that way. the piston skirts beeing broken look to me like all damage from the rod coming apart. if the piston pin was jerked out of the piston with out the piston being stuck i would say you could blame the piston. i have broke the skirt off several 2 stroke pistons over the years which happens from to much clerance from piston and cylinder wear and never broke a rod from breakin the skirt which they were all older ski doos and cats yamahas and polaris with high miles have broke the cases but not the rod. which is why i recomend you change your pistons any wear from 1000 to 2500 miles depending on how ridden and how many mods. i do know the new doo engines are not as reliable as the old ones. but that is only my opinion . you didnt show me any evidence of the piston being the faliure i think the rod failed and that is why i cross my fingers on all new engines for the frist night of racing or the frist hard ride becuase defective parts are gonna show up then i have seen lots of pistons with the pin ripped out of the piston with out being stuck that would be a poor quality piston. but i am not a 2 stroke engineeer this is al my experience and opinion just tryin to help i sure hope you find any engine soon lots of good riding left have a great day dan

 

[yotaman1290]

When you rebuilt the motor did you replace the oil check valves in the motor case from the oil pump or even check them. I have two 06 800 revs and both have had new motors after oil failures and found bad oil check valves. The first skidoo blew at 425 miles and the second at 2400 miles.

There was plenty of oil in the cylinders and on the pistons when i took it apart. Like i said, i had pre-mix in the tank too!

 

[bustamove]

i had a set of spi on my 900 poo that let go and took out cases within 15miles with everything you did with pre mix etc... no snapped rod though

 

[yotaman1290]

Well, i got her together and it runs great. Compression readings were pto- 130 and mag- 140 BEFORE start up! Not bad, but should jump way up when rings seat. Anything you guys would recommend before i take it into the hills?
I will run 50:1 premix first two tanks, i bled oil pump, and riding it easy for a while...

Here is a pic of my sled-

 

[Reeb]

I've seen dozens apon dozens of Doo's with failed motors and never have I seen a case explode like that. Not even a BB at full throttle with a lower bearing failure took the cases out that bad......crazy

Are the pistons you used Hyperdrive pistons? If so, they are made by Namura for SPI. Namura also supplies BRP with pistons for all E-Tecs. Infact, the coating on the pistons is a registered trademark of Namura and Doo uses the same coating exclusively.

And I don't care who you are, never just throw a piston in a hole.....cylinder measured to spec? Who cares! If the piston isn't mated to the cylinder, specs mean nothing.

I have a 06 as well and as preventative maintenance a new shortblock was put in, this summer it should have about 1500km on it, was thinking of tearing apart but more than likely try to get another year out of it, should last to 3000km I'm hoping.

Hate to see it happen, good luck!

 

[eddy]

Blown Engine

One picture shows the wrist pin bearing where there is big time clearance between the rod and the piston. Caged bearings as well. I wonder if the side load took out the rod when it rocked to one side causing the catastrophe?

 

[yotaman1290]

One picture shows the wrist pin bearing where there is big time clearance between the rod and the piston. Caged bearings as well. I wonder if the side load took out the rod when it rocked to one side causing the catastrophe?

I dont know. Who does!?!? I sure wish i did..
Its been good so far with OEM internals.. I have had it out twice and it rips hard.
Both holes are at exactly 150psi so thats great. Hopefully she will be good for me, cuz i cant afford another stinkin motor!!!

 

[mbret2004]

Did you check the bottom end connecting rod clearances? Specifically, the measurement between the rod and the thrust washer. If this distance is too great you'll wear out the bottom end rod bearing leading to excessive radial deflection or excessive vertical play between the bearing and rod. Too much radial deflection leads to more severe issues. The already worn bearings continue to wear and develops too too much torsional movement. Torsional movement is where the rod begins to to twist on the worn bearing. Impending failure is a sure bet.

The measurements should be checked when ever a top-end rebuild is done. You can do everything correctly on the pistons and bearings and accompanying measurements but if you don't check the bottom end your chance of repeated failures are increased exponentially.

Good luck.

 

[yotaman1290]

Did you check the bottom end connecting rod clearances? Specifically, the measurement between the rod and the thrust washer. If this distance is too great you'll wear out the bottom end rod bearing leading to excessive radial deflection or excessive vertical play between the bearing and rod. Too much radial deflection leads to more severe issues. The already worn bearings continue to wear and develops too too much torsional movement. Torsional movement is where the rod begins to to twist on the worn bearing. Impending failure is a sure bet.

The measurements should be checked when ever a top-end rebuild is done. You can do everything correctly on the pistons and bearings and accompanying measurements but if you don't check the bottom end your chance of repeated failures are increased exponentially.

Good luck.

I didnt check those clearances.. The motor only had 1800 miles on it and cranks will last a heck of a lot longer than that.
I rebuilt it to ensure a good motor, NOT because it blew up..