yea, I figured I can get a Porsche jacket and maybe a coffee mug. Damn white of them I say... Sarcasm intended!

 

kozzimo - am I correct in assuming you find the bolt heads by dropping the oil pan? Does that require dropping the engine or removing it from the subframe?

 

Man I have to admit, I didn't get a good answer on the missing bolt head or 2. An oil change seemed to be my SM answer to the missing heads. He actually said they drive it before they changed the oil to make sure they caught anything bad. Good grief, I just shook my head, thinking well it all checked out and it drives great. Should I be worried? I feel it

 

If you are concerned, I would pull the pan and pickup tube on your next oil change. The pickup tube is only held on place by (2) E-10 torx bolts. After you drain the oil, it takes less than than 5 minutes to drop the pan and pull the pickup tube. Give that thing a couple light smacks and dig around with a pick or bent wire - you'll find them. My brother has seen this on some BMW's in the past.

 

Appreciate the advice. I Will give it a shot

 

Pictures are mandatory.. (or nicely requested..)

 

The new bolts do not have the anti-taper feature, which doesn't matter to me at all. They simply have a dark PTFE-based coating coating on them (aka Teflon) that practically scratches off with your fingernail. Just as the previous bolts, the new ones also do not use any type of loctite/threadlocker. The new bolt head has a taller head-height by about (0.6mm). Measurements are simply showing more tool engagement.

Typical 6061 Alloy has a yield strength of about 40KSI, while "aircraft" grade 7075 Alloy is about 73KSI (nearly comparable to grade 5 Titanium). 7068 is arguably the most badass alloy out there for strength-to-weight (99KSI yield), but we all know that Porsche would not have paid 4 times the cost of standard 6061 to have something this superior. I am half tempted to send in the two samples to identify any property changes at all. If not, then all 2012+ owners better get ready for some failures, and Porsche better get ready for a big-time recall nearly identical to the 1/2 million 3-Series that BMW dealt with on their failed vanos sprocket bolts. I have also heard that the same manufacture of this cam adjuster for Porsche, was responsible for the BMW issue that lead to recall, only this issue has the potential as an extreme safety concern.

I am not sure what Porsche's sales figures on the Cayenne and Panamera, but at this point I am considering having at least 10 million properly specced out bolts manufactured and sell them to Porsche when the recall takes place

I will continue to research and report my findings, but does anyone know about the properties of PTFE coatings and why they may have done this?

Also, if there are other threads or forums on this topic, someone please pass this information along to spread awareness of the situation.

 

Keith - I'm sure you do know titanium is also non-magnetic right?

So far - I haven't seen any reported failures of the Variocam adjusters on engines that received the new adjusters with the new bolts - have you? Certainly some of the early ones have accumulated significant mileage by now. They started to be used in 2012 - I would think we'd have heard of them failing if they're going to.

Have any metallurgical tests been done on one of the new bolts to determine just what alloy it is? Has a spectrometer test been done on the coating to determine it's PTFE?

BTW - "!!!!" and all caps seems a bit dramatic.

There are other forums and threads about the subject - but without answers to the above - I'm personally not passing it along. This IMHO is the definitive thread on the subject at the moment - so it should receive plenty of exposure right here.

 

Common sense tells me Porsche, internally acknowledged the failure. Surely they would not be so stupid to look for a

dollar savings on bolts, on a redesigned component. Let's not get to far ahead of ourselves on this one. I have to believe they have fixed the problem , I have to believe they know when to cut their losses.

 

Out of curiosity - I did some titanium vs aluminum bolt research. Titanium bolts do cost more than 7075 bolts - but not even twice as much. They are a bit heavier (1.6x) for the same size bolt, but they also are roughly 2X stronger for all parameters I could find. The metal itself has better stretch qualities than aluminum.

So the hope is - they're titanium bolts. The difference in cost for the 8 bolts involved would probably be about $16/engine.

If not - and they are 7075 bolts - my WAG is - the original bolts were not 7075 aluminum. The heads on the original bolts are very soft. Using a brand new security Torx driver (decent quality one - cost about $15) - it cammed out of the Torx recess, and the aluminum was damaged. To me - that indicated soft aluminum.

As far as the coating on the new bolts - dunno - I didn't try removing any from mine. As Keith suggested - I did go to the garage and test them - the new bolts aren't magnetic.

Keith - I looked at where you work - and I'm guessing you may have some access to QC equipment that might prove enlightening.. only problem would be sourcing some of the new bolts for some destructive testing (yield strength would immediately be interesting.)

 

Haha, thanks Don. I was really going for dramatic on this one.

I also have not seen any reports of failure with 2012 and up, and I hope we don't. I am with you though and I really hope they went to 7075 or something similar, because I guarantee they tried to get away with 6061 on the first batch. The only idea I can come up with about the new coating is that a teflon-type coating would allow the bolts to enter the housing with less friction, which in turn allows the same torque with more holding force possibly.

I have had some experience with a couple types of titanium in the past, and they were all semi-magnetic. Plus, it think Porsche would heavily tout the "titanium drivetrain" statement if that was the case. My choice here would be 7068 aluminum, which would beat out titanium in all aspects. If I end up manufacturing a "preventative bolt kit" it will be 7068.

Yes! We do have some awesome equipment for testing, especially hydrostatic explosion stuff I wish I had these bolts in hand a week ago because we had a handheld XRF spectrometer that I could have checked them with....

 

The original cost of the vehicle is immaterial. This sort of failure wouldn't be acceptable on a KIA Sorento either (and they'd probably do something about it..) As far as them not being titanium, because they don't tout it - I think they want to keep VERY QUIET about any material change in the bolts.. VERY VERY QUIET..

 

​​​​​​well my SM wasn't quiet about it. He clearly stated the replacement units had steel bolts, and we're a driect response to the aluminum bolt failures. Maybe he didn't get the memo from corporate

 

This is an excellent point... Let's hope they did something right with these new bolts. Either way I am going to looking into making some grade 5 titanium bolts in bulk and give people peace of mind if they want to replace their current bolts.

 

I was in today to speak with my mechanic about another issue. I asked him about the replacement bolts. He felt highly confident these were titanium. He had one handy, and although the magnet would not stick, he attempted to scratch it, and nothing. So if they were aluminum, it coated, you should have been able to tell. He also stated that they are heavier than any aluminum bolts would be.
theres your piece of mind for the day.