Porsche reveal cause of 991 GT3 fires

The pair of engine failures that caused two brand new Porsche 991 GT3s to ignite were the result of a problem with a piston connecting rod bolt. Speaking to Total 911, Porsche GB Product Affairs Manager, Nick Perry, explained that “the broken connecting rod bolt caused damage to the crankcase” of the burnt out GT3s.

After a ‘stop driving’ notice was issued by Porsche four weeks ago, Zuffenhausen has been flat out in an attempt to diagnose the cause of the two catastrophic failures. Just last week, we reported that there had been little further news from Porsche regarding the issue.

However, today’s news (which 991 GT3 owners will be receiving in letter form imminently) signals the major breakthrough that all 785 owners have been hoping for during the past month.

Porsche 991 GT3 update
Porsche has confirmed it will replace the engine in every 991 GT3 delivered so far.

Porsche have not confirmed if the two bolt failures happened at the big- or small-end of the conrod but, rather than replace the offending items, Stuttgart will now embark on the process of replacing the engines in every 991 GT3 produced so far.

Perry did not want to put a timescale on this process as many of the 100-odd GT3s delivered so far in the UK will need to be recovered to an OPC, and the engines need to be built and transited from Germany, before the motor switch can be performed.

The new engines, which will feature an improved connecting rod bolt, will also feature on any new 991 GT3 rolling off the production line as of today. While the end appears to be in sight, Total 911 will keep you abreast of any further developments.

Comments (3)

  • the1beard

    Shocking incompetence.

  • Karl Richardson

    I’m not sure I get how a con rod bolt can be directly linked to a fire and yet there be so much head scratching amongst Porsche’s engineering team. Lets face it, they will be pretty clued up peeps wouldn’t they. The only scenario I can see from a con rod bolt failing leading to a fire would be if the bolt failed and it “threw a rod” out of the side of the block, leading to the engine oil hitting something hot (like an exhaust manifold) causing the oil to reach it’s flash point and ignite. Now if there were to happen, the evidence left over from a burnt out shell would likely still be present making the con rod failure an easy spot. Now if it were just a problem related to the con rod bolts….. why would it be necessary to replace the entire engine? Surely the rod bolts, or even all the rod assemblies could be replaced at a fraction of the cost of a new crate motor install. I also find it strange that in todays day and age, with the level of R&D that Porsche throw at every aspect of their cars (including powerplants) that this has come as total surprise to them. Surely with the stringent tests their engines go through an issue like this would have been resolved before it had chance to rear it’s head in a real world scenario.

  • FP

    Defects are present in every machine engineered. This isn’t the only part that will break on these cars nor are there cars free from part breakage. We should also consider this may not be a engineering or material defect instead it could be an assembly issue. Fitting new engines is likely quicker and more reliable than what amounts to an engine rebuild. As the owner of a new GT3 would you rather Porsche swap in a new engine in a day or have your current engine disassembled for significantly longer? Additionally, if they so chose, they can use the old engines for more development or refurbished parts. Certainly they’re all low mileage.

    IMO this is a fine response from a responsible company which made a small mistake.