Jesh I feel for all of you. Porsche is going to take a serious hit in the next consumer surveys I fear.

Try and hang in there people.

 

Though I cancelled my order I still stay in touch with the SA. Did my weekly check-in today... car is still sitting in the Florida sunshine at port, with no further status updates available, and no new GTS/GT4/Spyder allocations falling out of the heavens.

 

I'm in Canada and my SA called to tell me they started to work on my car today.
I think I was a bit of an outlier for selecting con-rods swap to gain a month advantage over full engines, so I thought.
Turns out someone at the same dealership got his engine swap last week.
I'm not out of the woods yet as my SA also mentioned that if the rod bolts were not torqued to spec, they will need to replace the engine...

 

Not quite, as long as they are above 23nm then they will just replace, that’s really loose! Mine were 58nm which is still pretty loose but fine for the rebuild.
I’d mentioned above that my mechanic said he didn’t think they’d been tightened properly in the first place as he can’t think of any other reason they’d be loose in a brand new car.

picking mine up on Friday but not holding my breath just yet!

 

The reason stated by Porsche was stated by Porsche as "A potential defect in the surface of the connecting rod could lead to cracks, creating a loss of preload on the connecting rod screw connection.".

I read this as the resulting lower torque is not from them not being tightened enough when installed, but due to the bolts losing tension over time as a result of the metallurgy of the surface of the connecting rod not meeting standards. I could see how this would have been impossible to detect at the time of installation since there is a factor related to the time the metal is under stress. That's just my layman's interpretation though.

 

Totally get where you are coming from but why would they be loose in a brand new engine though?

 

According to reports the company that made the "bad" batch of connecting rods in question was Hoeckle Austria GmbH. They did not meet proper Porsche specifications but Porsche did not detect this for some time since I assume they can't test every batch of every part all of the time. Often problems with metal fatigue are not immediately apparent and only show up after prolong and repeated stress over time. So they appeared fine in the brand new engine, but over time and with repeated usage cycles the problem started to exhibit itself. As the rods fatigued it caused the bolts to loosen.

Most articles I see when Googling metal fatigue mention time and stress cycles as revealing the problem. The engine builders would have had no indication there was a problem. Here's a quote from one: "Metal fatigue is one of the subtlest types of metal failures". At least they figured it out before a lot of engines failed like happened with the 991.1 GT3.

 

I’d read that elsewhere but again it doesn’t explain loose bolts in a brand new engine with no miles on it

 

The bolts might come loose because of the "soft" rods... that's my take.

 

maybe only a few miles but it may just take some heat cycles for the problem if the rods aren't up to snuff.

 

Surely they test the engines before they assemble them to the car.

 

I thought it was a miscalibrated torque setting on a machine somewhere at either the Hoeckle or Porsche plant. Running the engine with insufficient torque on the rod bolts causes them to loosen up even further, leading to damage when the tolerances get too far out of line. Sounds like more specific info has come to light?

 

Good news !
I was told this afternoon that they can proceed with the repair and I will likely take delivery next week.
Hang in there guys...

 

Sounds great! Good Luck!

 

Regarding the torque discussion, let me try one more time. The torque problem wouldn't show up during the build process where everything would torque correctly. It wouldn't show up in an initial test of the engine or probably even after several runs of the engine unless you tore down the engine and examined everything knowing what you are looking for. There is no way they could have detected this in individual engines in the factory, even after a test run, without tearing the engine back apart.

I am aware that they do occasionally pull an engine from the assembly line, do more vigorous test runs with it, then tear it down to make sure everything is as expected. I would guess that this is where they detected this problem but that's just wild conjecture.

​​​​The problem apparently only shows up after one or more stress cycles. The connecting rod material doesn't maintain its strength as expected after being run, and apparently from the reports above it doesn't take many runs for it to become detectable IF you tear down the engine and look for it. Your car is started and run several times during the transportation process and there are miles and engine cycles on every car delivered so there is no thing as a car with no miles on it (or engine runs). (Trivia item: The Porsche ECU actually counts how many times the engine is run and how long it runs during its life. You can ask for this report to be pulled when you are examining a used Porsche for purchase. It also includes a report on over-revs to help detect a car with a dangerous mis-shift - aka a money shift).

This reminds me of a warning on a trailer my son just bought that reads: "Wheel nuts/bolts should be torqued before first road use. Check and re-torque after the first 10 miles, 25 miles, and again at 50 miles." This is a manufacturer acknowledging that it takes just a small number of load cycles for torque values to change regardless of how properly bolts were torqued at the factory. Certainly trailer wheels and Porsche connecting rods/bolts are in a whole different class of course, but it does show the concept that manufacturers expect torque values to change on metal items after some use. In the case with the Porsche connecting rods, they are just changing far beyond expectations due to a manufacturing error from a vendor and that is what they recognized and are fixing.