Broken M96 crankshaft- X-51s fail too!

[MikenOH]

For the less educated, could you explain how a crankshaft is created from powered metal?
Weren't cranks forged in the old days from a solid billet and then machined?
How would you compare the new technology to the old--durability/price?

[JP-s-in st. louis]

Ooops how the hell did this happen? The motor should have an electronic babysitter to keep the limiter from allowing it to downshift that probably caused this.

Oh well the electronics will only save so much. It will not save it if you go from 4th to 1st instead of 4th to 3rd.

[Jake Raby]

Originally Posted by JP-s-in st. louis

Ooops how the hell did this happen? The motor should have an electronic babysitter to keep the limiter from allowing it to downshift that probably caused this.

Oh well the electronics will only save so much. It will not save it if you go from 4th to 1st instead of 4th to 3rd.

The engine was never over revved.. It had no signs of any over rev in the valve train and the remainder of the engine looked great inside.

The driver just heard a large bang and then a rattle- He thought the engine snapped a rod in half and so did I until my initial inspection before tear down.

I have never seen a crank snap in any engine from an over rev, the first thing that sees over rev damage is valvetrain components.

[Lil bastard]

Originally Posted by Jake Raby

The engine was never over revved.. It had no signs of any over rev in the valve train and the remainder of the engine looked great inside.

The driver just heard a large bang and then a rattle- He thought the engine snapped a rod in half and so did I until my initial inspection before tear down.

I have never seen a crank snap in any engine from an over rev, the first thing that sees over rev damage is valvetrain components.

+1! The limiting factor in engine revs has always been the reciprocating gear - Valvetrain, Rods/Pistons and ancillaries... never the rotational components!

Pressed Metal technology is 'better' from the standpoint of 'controlling' the mfg. variables and cost... but ALWAYS at the expense of reliability/durability.

Just another example of Porsche's increasing arrogance - spend $50k+ on a car... get a pressed metal crankshaft... beautiful!

[wvicary]

Originally Posted by Lil bastard

+1! The limiting factor in engine revs has always been the reciprocating gear - Valvetrain, Rods/Pistons and ancillaries... never the rotational components!

Pressed Metal technology is 'better' from the standpoint of 'controlling' the mfg. variables and cost... but ALWAYS at the expense of reliability/durability.

Just another example of Porsche's increasing arrogance - spend $50k+ on a car... get a pressed metal crankshaft... beautiful!

I thought the engine did rather well considering it has an aftermarket flywheel and 12,000 track miles.

[Jake Raby]

Originally Posted by MikenOH

For the less educated, could you explain how a crankshaft is created from powered metal?
Weren't cranks forged in the old days from a solid billet and then machined?
How would you compare the new technology to the old--durability/price?

The newer methods of component manufacturing consider cost more than longevity- just like the rest of the M96 engine- thats why they fail.

Older cranks were true forged units, typically 911, 356 and 914 cranks were 1045 steel forgings made with conventional methods.. A google search on the topic will explain exactly how a crank is forged and it'll be easier to comprehend than anything I could explain in the 10 minutes I have to make this post :-)

[Brucelee]

Originally Posted by Jake Raby

The newer methods of component manufacturing consider cost more than longevity- just like the rest of the M96 engine- thats why they fail.

Older cranks were true forged units, typically 911, 356 and 914 cranks were 1045 steel forgings made with conventional methods.. A google search on the topic will explain exactly how a crank is forged and it'll be easier to comprehend than anything I could explain in the 10 minutes I have to make this post :-)

Given the price of these cars, it is pretty sad that Porsche is thinking low cost on something like a CRANKSHAFT!!!!!!!!!!!!!!!!!!!!!!!!

I can see this if I am buying a Yaris or other toss away car.

Man, this is pretty pathetic for a company like Porsche.

[Topless]

+1 on the lightweight flywheel issue. Now knowing I have a powdered crank in there I appreciate the flywheel's rotational mass soaking up most of the engine killing harmonics in my street car. If it were an F-1 motor that only had to go three races I might feel differently.