FWIW, m10 conrod nuts for a 928 engine get 75 N-m (54 ft-lbs) and are single use. For the stock bits.

For custom stuff - like Carrilo rods - you measure bolt stretch directly; that’s the best way to get a specific clamping force.

 

Boom, there you go. I wonder if this issue is only a big end bolt problem or are they replacing the conrods too??? Where I come from, I would think bolts are the most likely issue here and its a swap of the bolts without taking pistons out.

Anywho- all real interesting for those that get tear downs and bolt replacements. PCNA wasn’t too forthcoming late last week when I talked with them on my engine replacement schedule - “No nothing, sayin nothing” …….waiting, waiting, waiting….

 

The rods are definitely being replaced also

Here’s the box of new rods going in

 

Loose bolts? Eh, that's what Loctite Red is for. Git 'er done.

 

Hmmm Porsche is not taking chances - if the bolts were loose when the engine was fired, then the rods could have gotten deformed - hence new rods. I bet there is an inspection protocol on piston skirt and bore scoring. Good on Porsche for not holding back

 

 

My dealer and SA have not heard anything either.

 

Your SA replies to your emails? Lucky you.

 

The "complicated answer without a figure" might be a torque angle signature that has to land within an envelope from initial 'snug' to final tension. Torque is used to perform the work, but the angle at each increment of torque has to be within certain boundries based upon tests done on mock-up engines. Or, it could be torque for installation verified by measurement of length change in the bolt by ultrasonic or direct mechanical measurement.

Taking Porsche at their word (from the recall) the problem was "Connecting Rods that did not meet specifications" and not the bolts. The con-rods are manufactured by Hoeckle. The con-rod bolts, most certainly, are manufactured by someone else --- as it is a totally different forming technology and expertise to manufacture high-strength fasteners.

That said, something as simple as threading taps that wore beyond specification limits can lead to negative impacts on the torque-tension relationship. A worn thread tap used to tap the female threads in a con-rod would result in lower tensions in bolts tightened to the prescibed installation torque. The head-scratching part of the discussion for me is any talk about there being value in using torque to inspect installed bolts. Regardless of the direction one turns with a torque wrench during such an "inspection" the scatter in the break-away torque is significant, making the practice a waste of time.

One last comment relative to the comment on Loctite (or any other product): Adding it changes the friction-factor and necessitates doing mock-ups to quantify the changes that need to be made to the installation torque/procedure. If you ever rebuild your 4.0L NA engine be sure to use the exact same lubricant as used by the OEM.

Just happy to see Johnycarrera's car finally getting done.

 

Needless to say, I was kidding about the Loctite.

Another possibility is that they are too embarrassed after the GT3 debacle to admit that the bolts are again the problem. Might be time for a new bolt vendor, I'm thinking.

 

Really happy for johnycarrera!

 

+718!

 

Thanks guys……


what he said about the torque settings:

​​​​​​“Torque has 2 step procedure with torques and finishing off with an 80degree turn”

 

Anyone else tired of waiting and no updates???

I have an email from Porsche vp dated April 6th “from what we know now the engine replacement will be 3-6 months from now”

i emailed him today and said it’s been 3 months - no updates - how is this possible???? I guess they just don’t care I paid $108,000 for a new car not one sitting in Baltimore port sun and elements for who knows how long.

I am just about done I don’t need this car that bad. Porsche has set new standard for terrible customer service

 

I too am very frustrated about the lack of status. Its been long enough that the “path” is understood and thus it should be communicated for whatever that path maybe. I have a lot of things that commits my time and attention and I need to understand what i give priority to. Its time to tell people what is going on