Gen 1 sho 3.0 motor blown, crank snapped apart, pics

[chrism3784]

Driving back from virginia to florida, 1200 mi each way, literally 10 miles from my house the crankshaft snaps apart, sounded like the motor exploded, oil pan broke apart. No idea what caused this. Had good oil, oil pressure seemed ok, no light. Freak thing maybe? Maybe has something to do with the underdrive pulley, since it doesn't have a dampener, vibrations slowly cracked it?

 

[rubydist]

bummer! I bet that 'bang' got your attention...

 

[zoomlater]

Wow

 

[itwonder]

Hope you can find a JY replacement without too much trouble. I'd ditch the aftermarket pulley.

 

[SHOVNST]

I have a hunch the aftermarket pulley is at minimum partially to blame.

 

[kevinspann]

Was this a reman crank?

 

[Toolman]

Carnage!!

 

[zak]

Was or is this car supercharged or NA? Usually the underdrive crank pulley only takes out cranks on supercharged cars (yours might be the first NA victim - miles?)

 

[sperold]

With all the rods still attached to the crank journals, what took the bottom out of the pan?

Did the crank break in the center section of the block?

What does the top of the engine look like, are the pistons intact?

I have a limited imagination, so I cannot imagine what happened here. But here is one thought; what would happen if the firing order went out of phase and plugs fired long before the piston was near the top.
With the drive wheels demanding the crank location being at one place and the shutter wheel demanding power strokes that do not coincide, could that stress a crank to the point of breaking?
If this sounds crazy, I have to agree, but everything else seems even more crazy.

I would look at the shutter wheel and the crank sensor for a clue on that presumption.
Does not having a traditional crank pulley affect the shutter wheel in any way?

 

[pjtoledo]

examine the crack surfaces. if there are any smooth areas the crack has been working for a while. if the entire crack surface is jagged it was most likely an instantaneous event.

why does the crank look a lot cleaner than the rest of the components?

 

[pjtoledo]

Was or is this car supercharged or NA? Usually the underdrive crank pulley only takes out cranks on supercharged cars (yours might be the first NA victim - miles?)

not the first N/A crank breakage. there was one in Michigan 12-15 years ago.

 

[tompumped]

I've been running a shosource soid pulley since Dec '10 and it's my daily driver that i'm not easy on by any means. I am leaning more towards the fact that it serves a purpose as designed. My experience isn't sufficient enough to make a determination.


IIRC the motor in the thread was rebuilt, but i'm probably getting it confused with another thread as I couldn't find it through a search of his username.

I'm not sure if it was these engines, but people have recommended against using machined cranks with undersize bearings, because it changes the fillet of radii of the crank. People in the past experienced breakage as a result.