Ever seen 8 rods disintegrate at once?

[hoffman900]

8 rods going instantaneously, I’d be looking at everything that would effect all cylinders (tune, etc). Sometimes blaming the rod manufacturer is like blaming an electrical fuse manufacturer. Sure it could be the rods, but it could be a lot of other things as well.

[digger]

What gets me is the failure is almost identical cylinder to cylinder, separation just under the gudgeon pins,

SM posted another video and he said this was not the case the failure was mostly midway through beam not close to the pin as people questioned the mods he did for clearance in the pin area and whether these were a contributing factor

to me that split down the guts looks more like brittle failure which is not normal. but this is a different failure right as in not same engine?

[DCal]

Just curious if a rev limiter was being used?

[billet]

Steve did say these rods had not been in anything of that power level so far

Dcal: Looking at the data Steve showed, while not 100% on this it did not appear he was on the limiter but again a guess from what data he did show. IIRC think 8600 was the RPM it let go. If you look at the data when it broke the crank slowly slowed down, meaning there wasn't any of the motor trying to lock up the crank just slowly slowed RPM.

[lefty o]

Steve did say these rods had not been in anything of that power level so far

Dcal: Looking at the data Steve showed, while not 100% on this it did not appear he was on the limiter but again a guess from what data he did show. IIRC think 8600 was the RPM it let go. If you look at the data when it broke the crank slowly slowed down, meaning there wasn't any of the motor trying to lock up the crank just slowly slowed RPM.

im pretty sure the crankshaft did not break, just the 8 rods.

[hoodeng]

Digger, the rod failure i posted is not the same engine.

I would imagine the OP would have indicated if the failures were instigated at any point of modification? i see no mention of this, is it the case? ,, But for all to do the same thing in an instant?? My answer is to buy lottery tickets as the owner has now used up all his allocation of bad luck.

You are right Dave, it's a nitro Harley, and yes, cleaved the rod down the middle, the tops punched out the valve relief pockets, and yes the grain of the rod is exposed in the face on shot. The top bearing shell was squeezed in two, there was no distress in the bearings, there were no beach marks at any point on the fracture line.
The engine was unloaded off the line and got 60-80ft out flared and popped, i have seen a few of these busted now under similar circumstances but not like this, it was not a rod failure but as pointed out a result of other influences.

Cheers.

[allencr267]

Here's Part 2, I've got nothing on something usually malleable breaking like tempered glass.
Enjoy?

https://www.youtube.com/watch?v=rJnEQSXUOLo

[hoodeng]

He gave a comprehensive rebuttal to the hypotheticals proposed. Be that as it may, all at once in the same millisecond??
Even if the rods were made from recycled coat-hangers, i still struggle with the time frame and duplication of the event, c'est la vie!

Buy lottery tickets now!

[Dave Koehler]

He gave a comprehensive rebuttal to the hypotheticals proposed. Be that as it may, all at once in the same millisecond??
Even if the rods were made from recycled coat-hangers, i still struggle with the time frame and duplication of the event, c'est la vie!

Buy lottery tickets now!

That's what makes it so interesting and kind of cool in that regard.
Some one off material that showed it's weakness and/or limit seems the most logical.
Eventually Steve will let us know.

[RAS]

The rods had no discoloration, so they weren't starved for oil. Thousands of little pieces. They exploded. Much we don't know.