Cannondaleriders

Crank broke... the only thing I can think of is that I use a impact gun for the flywheel, and I have swapped that a few times coz of cracking flywheels...

I also noticed the exhaust valves hit the piston. And the piston also hit the head.

And something got into the scavenge pump for the valvetrain, and cracked the pump. I think it's a piece from a valve spring.

The only good thing is that I can get this engine running again within a few days. I have enough parts laying around here.

Whelp, at least you wont need a press to get the crank apart!

Thats like what happened to MyDreamrides crank. Unreal how something that big could break. At least your rod looks good. Does look like exhaust valve hit piston. Best to replace the valves.

Doubt it was the impact. We use the impact on 110psi, and have been for years. No problems.

Impact doesn't affect the flywheels either, I believe Wistech proved that experiment.

No, Wistech proved a impact did in fact distort flywheel hub which would lead to failed flywheels. Obviously that's not what did this crank in. Odds are it was a machining defect like the Falicons missing the radius on the flywheel stub. Any sharp corner or defect will concentrate stress and lead to failure.

SlOot, make sure you inspect the sealing surface on the head, it looks like your sleave may have been moving and put a groove in the head, that looks like what mine did and I lost the cylinder oring.
Also, it is hard to tell from the photos but if you inspect the broken crank you may notice a shiny area, that is likely where the crack started.

Do you have the thread from the flywheel test Steve? I am remembering it differently, and cannot find it....

Yeah, I doubt thats from an impact gun. sucks man, just plain sucks.

I have a pretty good memory and when I don't Timbo reminds me. The hub distorted .004in when impacted. Zero when torqued to 35ft lbs.

Probably a good note for everyone. Not sure how many hours/years were on this crank, but everything fails eventually. Doesn't matter updated or not. Have to figure some of these cranks have been in these motors for 8 years. That is a lot of time.

Cranks, rods, pistons, they all get stressed over time. Even if they look good and are still within spec., doesn't mean there aren't stress fractures or weak spots developing.