Picture 1: This is what happens when you don't use the best quality tools that you can get: you get to spend more to fix it!
2: broken (hollow) camshaft
3: ims bearing. Still turning, but with a little bit of roughness. 109k miles.
Caspar Labs tells me that they have sold around 75 or so of their ceramic bearings. I'm thinking of going with them. I'll post my results here.

 

scariest. picture. ever. There must have been a manufacturing flaw, the cams don't even look worn, how the heck did the shaft fail? Is there a busted sprocket or a snapped chain your not showing us? This picture is the stuff of nightmares ...

 

No other damage, except all of the bent valves from a skipped tooth in the valve drive somewhere. I'm mystified myself.

 

Valves are bent on both banks?

 

All 24 of them. I had to replace some of the guides also, due to bellmouthing/cracking. I had the machine shop replace them all. My guess is that the ims chain tensioner dropped, allowing that chain to skip a tooth: that's the only one that would do that much damage to both banks-unless I'm missing something.

 

Or MOF#24 which is a failed/ failing IMS assembly, not the bearing. Something similar to this:



These can partially fail and the cams will remain connected, but the cam timing is retarded and will usually bend only exhaust valves.

With these failures you have to find the smoking gun, or you'll revisit the problem later. The tensioner paddle can be at fault, as well as its wear pad, that when worn enough can easily allow the timing chain that drives the IMS to "jump teeth", which usually happens at start up when the IMS tensioner is not pumped up.

I see cams fail quite frequently and they generally snap in half at that same point and its due to collateral damage from trauma elsewhere within the engine, like a valve colliding with a piston.

Check the pistons closely for crown and top ring land damage after they contacted the valves. I have exceptionally good used pistons for sale, we never reuse them and generally just throw them away.

Look over this entire engine with extreme attention to detail. I see some traits.

 

The manufacturer of that precision piece of (?) cutting edge engineering is:

Dr. Ing. h.c. F. Porsche AG.

Wow, you say to yourself, that's an impressive sounding name for a company that builds cars when compared to other car builders with names like Toyota, Ford, Chevy, or whatever. But what does it mean in English?

It means: Ferdinand Porsche, Honorary degree of doctor of engineering, Incorporated. Wait, you mean he has an honorary doctorate degree in engineering? So a university just gave him this fancy degree which he displays in a highly prominent position in the name of his company, even though he never formally studied engineering and graduated? Hmmm.

Oh, I get it now! Porsche was able to learn his trade by practicing on his customers through trial and error! Yes, I certainly see that. Unfortunately, I believed I was purchasing precision state of the art engineering from a manufacturer founded by formally trained engineer.

Let's just be thankful his doctorate is in engineering and not medical!!!

But when I hear "method of failure #24", I feel compelled to write a letter to the Vienna University of Technology, who issued that degree, to inform them of their grave lapse of judgement.

 

The first Porsche was built in a barn...

And Carroll Shelby was a chicken farmer.

 

No doubt, many talented people are of humble origin, which was not any point I was addressing.

I was highlighting the fact that Porsche prominently displays in its corporate name it's engineering credentials, which Porsche calculates the average person will rely on to ensure the product they were spending a hell of a lot of money on was of superior engineering quality. But that sadly, it's just not the case.

Consider this quote made years ago, today:

Ferdinand Porsche's motto was to produce automobiles which had to be reliable and of high-quality sports cars, of a high utilitarian value.

 

Thats before the accounting department was in charge of engineering.

 

Jake do you have YouTube vids of all the modes of failure? I find them very interesting to watch as most of us don't work on m96 very much, if at all. Reminds me of watching those "How It's Made" tv series, except on a different level.

 

No, I discovered lots of them years ago and never did videos with them, but have photo documented them. The normal failures are just another day at the office now, but MOF#24 is one I was waiting to see, because we knew it would occur due to the design of the IMS assembly.

I waited for 5 years for that one to find me :-) I was so damn happy the day that we diagnosed this one.

I have included the failures in my M96 Engine Bible, but have not decided which volume to insert it into.

 

Jake you saved the day again! After reading your post, and viewing the video, I went to the garage, picked up the IMS, and MOVED the sprocket for the IMS chain! Without your input, I probably wouldn't have noticed this fault, and would have spent a lot of time figuring out why the cams aren't turning when I tried to time them.
All 6 pistons are marked by the valves, so I'll contact you via phone next week in re: used serviceable pistons-along with another IMS.
Thanks again!

 

WOW!
That made my week, hell it made my month! I love helping to find these types of "smoking guns".

I tell people all the time in my classes that you HAVE to conclusively find and address the smoking gun after a failure, else you'll do nothing except waste your time and break even more parts.

I may have an early IMS as well, after that drive comes loose its impossible to get it straight again without runout that will break timing chains.

So glad I was able to help.

 

So maybe the name should be CPA F. Porsche AG

How many modes of failure for the M96 are you up to now?