May need a new motor

[Snowbird11]

this '08 700 from work has been just about totaled twice and now run w/o coolant. this is what the mag side looks like with the head off. i haven't looked any further but the piston is welded in there pretty good. I'm thinking it got hot enough to do some damage to the connecting rod and bottom end as well but won't know until i take it apart. any guesses where all that extra aluminum came from? everything above the cylinder head looks fine.

 

[assault 700]

whats the piston look like throw the exhaust hole and i have never seen that before

 

[SaskRMK]

I have to ask how it was run without coolant to the point of seizing it?

 

[Snowbird11]

whats the piston look like throw the exhaust hole and i have never seen that before

i pulled the exhaust valve and saw only minor scoring in the piston. i'm thinking about soaking it in a penetrating oil before trying to break it free. this one may be staying in there.

this was a hot seize that threw the rider over the bars. the pto side plug looked lean but there was still evidence of oil in the cylinder. the mag side had no oil and a bunch of aluminum on the plug. the mag piston did not appear to be scorched when viewed through the exhaust valve.

i'm honestly not sure if it was run w/o coolant first or if the coolant drained out as a result of the damage.

 

[Snowbird11]

I have to ask how it was run without coolant to the point of seizing it?

i'm still not positive this was the cause of the failure. my guess is that the rider did not see the light or notice any symptoms. it was a training session.

i did notice that the hose coming from the t-stat was thin and melted where it touched the oil container. i could not see a hole there but it was paper thin and had coolant on the wall behind it.

 

[Snowbird11]

well, the metal sticks to the magnet, so it's not aluminum. i'm guessing it's the piston skirt but we should know next week when we part the sled out. I'm keeping the engine to tinker around with and learn a bit.

 

[Snowbird11]

Pics

Here are a few pics of the top end damage and the case. Mag side is toast. PTO side isn't too bad but both halves of the case are damaged. luckily for us, this sled was a registered donor. the rest of the undamaged parts will live on!