Ok so I have this pic in my photo album and have gotten quite a few questions and comments about it so I figured I might as well post a thread about.

So first off here are the two pics I have of it.







And here is the story.

We have a couple customers over in Korea that we tune for. We take fly over with tools parts etc and tune their cars.

On this particular trip we had a new customer that was telling us his engine was making strange clicking and clunking sounds I do not know who built this particular engine but it was an FC with minor modification. The engine was said to have been rebuilt, broken in, and had settings done to it on a Power FC. The owner said the car was fine one day and the next morning it was making noises.

So when we arrived to take a look at the car the engine was still running!!! Yes it started and ran but had a loud clunking noise. Not a clicking but a CLUNKING noise. Before doing anything we thought maybe it was the flywheel or flywheel nut or something. So the tranny was removed and the flywheel and clutch appeared fine. However once we grabbed the flywheel it had a lot of front to back movement. So immediately we looked at the front cover E-shaft bolt and it also had play. At this point there was no other option than to open her up. What we found is what you see below.

So the owner for some reason or another is not telling his side of the story. Why I have no idea unless he rebuilt the engine himself and was embarrased? Any how what kind of situation would cause this?

We have the fallowing theories.

1: Insane RPM levels?
2: Tried to tow someone and at some point had a lot of slack in the line and the snap shock caused it??
3: One or many insane detonations??? (keep in mind he said it had been tuned)
4:... Any other ideas?

This happened about 2 years ago and that customer is just now ready to get a new engine in the car. He has asked us to build it and tune it this time so hopefully we wont see anything like this after the build.

 

Possibly built with the incorrect counterweights then, driven/raced with?

 

That is possible I suppose but I would expect that if the counterweight was mismatched enough to do this that there would be some earlier signs of problems.

Also I forgot to note that the engine internals were all in very good condition as was the E-shaft (aside from being broken).. You can see someone did some lapping work on the E-shaft.

 

Hrmm...I think one wouldnt know until the engine was revved high enough then caused a lot of stress. I could be very wrong though. My guess is the rear broke from the front.

I had my engine do some weird things once..it drove fine until you revved it past a certain point.
Finally it broke the rear key for the flywheel, and shaft kept spinning inside the flywheel. Instant rebuild...but all the rest was fine, just needed a new e-shaft.

 

hmm interesting point you brought up. If it was a mis shift or towing accident i would suspect some smaller part or area would break. Like the rear key or maybe strip some transmission gears or something.

The mystery continues...

 

I dont see how you could manage to snap it like that inless it was made poorly or incorrectly.

 

how did the endplay look?

 

Belt tension (excessive) can cause the E-shaft to sheer like this.

An Engine came into pineapple racing that had a similar break.

 

Turbo car? How much power was he pushing?

 

Holy ****. Amazing that it was still running, hell of a rotary.

 

i'm beyond speechless. i've heard of this, but seeing it is something on another level of perception and comprehension. holy ****!

 

wow.

 

Mt first assessment would have been a high speed/high rpm downshift that tossed the front apex seal, thereby locking the front rotor and front half of the e-shaft. The remaining inertia left in the drivetrain could have then sheared the shaft. Since you state the rotors, apex seals and I'm assuming the housings also, are still in serviceable condition, the only other option I can fathom are 3 general ideas.

1. Timing fired wrong causing the rotors to work against one another. Simply put, the front or rear rotor fired and tried to reverse it's direction.

2. Not rev matching a high speed/rpm downshift.

3. There was an inherent weakness in that part of the e-shaft.

Close up pics of the face of the break and side pics of the edge of the break may yield more info. The more twist that shows on the edges and face of the shaft, then the more time it took to fail. If no twist shows on the surface break or the e-shaft, then failure was sudden.