Yet another failure point..

[Jake Raby]

Just had a minute to share this one with you guys..
This is the hex key that drives the main oil pump from the IMS. Its powdered metal just like th connecting rods..

This cost a nasty failure.. Porsche NEVER upgraded this part all the way through M96 production.

We are now working with LN Engineering to make these from Chromoly steel and will be using these pieces in all future engines, just like the other upgrade parts..

This was one of MY engines and it totally wiped out the bottom end.. It was a 3.6 built from a 3.2 that was making 355 flywheel HP and revved as fast as a Carrera GT... In a Boxster S thats fully prepped it gave GT3s a hard time.

There is no better way to develop than through trial and error coupled with constant updates and pushring the limits... Repairing it isn't costing the customer a dime, he never even had to ask.

Breaking parts is part of my job requirements... This is our first engine failure, but I am sure it won't be our last.. Nothing would have lived through this, just thank god it had overbuilt components in the dynamic assembly, else it would be totally wasted.

[Cloudsurfer]

Ouch! Guess that's what you get with no oil pressure....

[Jake Raby]

Yep!! Could have been much worse!

[Cloudsurfer]

What about the crank? Looks pretty burned. Did the sleeves survive or are they scored?

[Jaxonalden]

Jake,

Looking at the shaft it appears to be bent. I would expect it to show signs of a twist break, could it be the hex shaft had an unseen internal crack? I can"t see why it would fail unless the oil pump locked up causing the failure. It obviously failed while running, could 60 psi of oil pressure stress snap this shaft?

Then again you did say "It was a 3.6 built from a 3.2 that was making 355 flywheel HP and revved as fast as a Carrera GT...". If it does rev that fast I could see a failure being imminent.

[Jake Raby]

The sleeves are perfect, so are the pistons, IMS bearing and 4 of the rods...

The crank is toast and is cracked. Since this happened on the track at over 7500 RPM lots happened all at once and it could have been much, much worse.

The hex is bent, but that happened after the piece sheared in half. Its easy to see that the piece simply twisted off from torsion.

The engine's throttle response is what did this.. It was unreal! The oil pump gears are huge and are very heavy, with them moving a ton of oil at those kind of revs lots of load is on this hex.. We never knew how much load until this happened.

Its all about finding the weakest links. As serious performance increases occur that weak link will continue to move from component to component and we'll continue to break things and find the limits.

Luckily this was a test engine, the first of it's spec and the Owner was so pleased that he barely cared that it failed... He knew we'd make it even better the next time around.

The chromoly hex is being made as we speak.. The engine is going back together with even higher CR and more head work with a new intake system. I think it'll easily break 375 at the flywheel..... all of that from an engine that used to be a 3.2 that barely made 215RWHP when I tore it down to apply "The Substitute" :-)

[edevlin]

Cool,


Ed

:dance:

[Boxtaboy]

To be fair, I don't think Porsche designed that hex key to withstand much more stress than their stock 3.2L engine would normally put out. It probably would not have failed if the engine were left alone, and not modded out to a 3.6L, 355hp (105hp more than the stock 3.2L engine normally produces) track car, no?

[Jake Raby]

This is the same part that is factory in a 2008 997 engine making more power than the modified engine I created, but without the throttle response.

I am building a 3.8 X51 engine right now, this is the same component that was factory equipment in that engine as well. They are the same length and weigh exactly the same.

Needless to say, I won't be completing another engine until the new component is completed as everything I have in my line up now has the same or even more performance than the engine that suffered this failure.

[Boxtaboy]

Originally Posted by Jake Raby

This is the same part that is factory in a 2008 997 engine making more power than the modified engine I created, but without the throttle response.

I am building a 3.8 X51 engine right now, this is the same component that was factory equipment in that engine as well. They are the same length and weigh exactly the same.

Needless to say, I won't be completing another engine until the new component is completed as everything I have in my line up now has the same or even more performance than the engine that suffered this failure.

If that's the case, then I stand corrected, and you've dialed in too much throttle response!

[Jake Raby]

Nope. Just found a new weak link and determined it's failure point.
Thats the key.
I'll find more.

[70Sixter]

God bless Jake and Charles!

[jmatta]

"you've dialed in too much throttle response!"

Wow, I'd sure like to experience that!

[jaykay]

The look of that porous metal gives me shivers....and used in a key application...wow

[BYprodriver]

Originally Posted by Jake Raby

Nope. Just found a new weak link and determined it's failure point.
Thats the key.
I'll find more.

As Carrol Shelby commanded while we were testing the then new 1999 Series 1 sport car, ( Break the S**t out of it !)

Maybe another reason Porsche endorses 0-40 weight oil

[Jake Raby]

This engine used 40 wt oil also...

I break things.. Its what I do. We learn more from failures than anything else, there are times when we force things to fail, but this wasn't one of them.

Luckily this was a test engine.

While depressing, this kind of thing is no surprise when a company chooses to value its accountants more than its engineers.