fritz:
reginos:

I was told by someone with connections to Porsche that the GT3 uses titanium con rods but they were secured in place with the normal steel con rod bolts from the Carrera engine. These couldn't be secured on the titanium and worked loose with usage and the higher revs, with the known results of crankcase failure, spilled oil and fire. This is supposed to be the root of the problem.

He didn't know the remedy to be applied. Different type/material of bolts? Same bolts but locked into place using some type of adhesive? Something else?

The GT3s have used titanium conrods since the first 996 version, so nothing new in that respect. I don't remember for sure offhand if the conrod bolts on earlier versions were also titanium, or steel.  Smiley  
Titanium screw connections can be a little tricky, calling for a very special (and very expensive!) grease to be used during their assembly as well as for fastening torque to be strictly adhered to, to ensure that the bolts are not overstressed if torque is too high or the bolts do not vibrate loose if the torque is too low. 

Since Porsche has been assembling production GT3 engines with titanium conrods for the last 15 years (and much longer than that in racing engines) I'd be surprised if they have now suddenly forgotten how to do it properly. 

For this reason I had suspected that maybe the torque calibration of a tool used to assemble some of the customer engine conrods may have been outside normal tolerances, resulting in the two failures of the conrod screw connections we have heard about. Since it would probably not have been possible to reliably identify the engines assembled with incorrect fastening torques, a simple error like that could result in all engines having to be replaced to rule out further problems. 

Thank you Fritz for adding your invaluable knowledge.

The knot is being gradually untied.

 


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"Form follows function"