I do believe that this is an open issue. If Textron updated the pump, I'm unaware of it. However, I do believe this is an issue that mostly presents itself during hard running, like racing etc. Speed says that replacing the impeller won't fix the issue.

I will probably do the update, but I want to wait and see how others rate it first.

 

The water pump is the reason the XX has had such a hard time finishing races from the beginning. It's the reason Dakar didn't go as planned. It's the reason Max was not in the Baja 500 when I was down there last year. They were breaking prototype impellers all week trying to find a solution. When they say it's been a long hard process trying to find the right design, they are not kidding. This one looks so much better than all the others

 

Dasa just released a new rev of theirs as well.

 

Looks like the old one...what is different?

 

I know that this is an older thread, but my water pump impeller just came apart, may have blown a head gasket also, any updates on the billet impellers? Thanks.

 

I put the Speed kit in mine and it was well worth the money. All gaskets and parts included in kit so no surprise when putting back together.

How hot did you engine get?

 

Not sure of the temp, the light was on, I had to keep it running to get back to the runway..engine was very hot. did compression test, looks like head gasket is blown between cyl 1 and 2 . I am worried about the rings.
I am running the engine in an "off road" vehicle, (aircraft) normally cruise around 6100-6800 rpm, will see as high as 8200 on takeoff. The engine has been running great for the last 75 hours.
I replaced the impeller 60 hours ago earlier this year as a precautionary measure.

I do like the way the speed kit is built, eliminating the through holes (weak point) in the shaft. I do know a couple of guys that just replaced theirs with the Dasa kit.
Thanks for any insight as this seems to be an issue that is happening with the aircraft conversions..Other than that I love this engine.

 

Aircraft usage is probably very, very similar to running with a CVT, so no surprise that the impeller is failing similarly.

I will install an electric water pump before the impeller gets a chance to fail (I hope). I ran the plastic version of the Davies Craig pump in my road-racing car mounted in an area with very poor airflow. No issues whatsoever in several years of racing. In addition to the pump controller, which gave me super good control of coolant temp, I added a DPDT switch that completely disabled the controller and ran the pump at full power. Never had to use the override.

That said, I might stay mechanical if a water pump failure meant I would fall out of the sky.

 

I am going to add an oil cooler also, to help keep the engine internals cool. Never ran hot before, but it seems like the dessert racers and aircraft are having failures, and mostly used in hot weather. The engine makes massive power for it's weight, and seems to be holding up well except for the pump issue, just happened to two guys in Texas also.
Falling out of the sky is no fun, gravity wins!
Here is a short video.

 

does your sky rig auto rotate or have a fast deploying chute?...

 

It is an autogyro, or gyroplane, it is always in auto rotation. The blades do not have collective pitch like a helicopter, and are not powered, the engine just provides thrust with a propeller.
So if the engine quits, blades still turn, and full control is maintained, Gyroplanes land very short.
It is the most fun thing you can do with a snowmobile engine when there is no snow.