Ebay - 991 GTS engine - bore scored - Page 1 - 911/Carrera GT - PistonHeads UK

Just happened to notice this ad on eBay for a 991 GTS engine with bore scoring. So I'm not trying to start any internet rumours unnecessarily but clearly this is possible with the newer dfi engine. Not posting any pics because the seller admits they're stock images. I will copy paste the description as that is worth keeping. https://www.ebay.co.uk/itm/334383513563 Porsche 911 GTS 991 3.8 MA1.03s Complete Engine MA103s. SALVAGE REPAIR BREAKING Engine has bore scoring in cylinder 3 confirmed by boroscope - see below results from leak down test Cylinder 1 – 6% Cylinder 2 – 8% Cylinder 3 – 28% Cylinder 4 – 8% Cylinder 5 – 8% Cylinder 6 – 8% Engine still runs, car drove well before engine removed and assume most of the rest of engine is still good for parts - 42,600 miles on the clock Engine currently being removed and have used a stock picture, let me know if you have any questions MA1.03S 3.8 PETROL GTS 991 Collection only - West London

It’s a known problem with DFi engines (not just Porsche DFi engine’s) it’s caused by a phenomenon known as Low Speed Pre-Ignition (LSPI). Google it, there’s a wealth of information out there on it.

Never heard of it LSPI, now I googled it there seems no cure.. more nails for ICE.

Oil companies have and are developing specific lubricants to solve the issues arising from LSPi

Any engine can borescore. Some BMWs developed a habit of borescoring the 90s, which BMW blamed on sub-standard fuels but was more likely to be an issue with the cylinder liners - BMW replaced a lot of engines outside warranty regardless of their blaming fuel. Porsche developed a huge reputation for borescore with the M96 / M97 engine due to the use of plastic piston coatings and lokasil cylinder liners, that was resolved with the later DFI engines. My personal opinion is that the 2 year oil change interval really doesn't help matters, and should have been kept at 12 months. All of our cars have a 2 year or 'on condition' oil service - but I won't run any of them past 12 months without an oil change. The fact that Porsche removed the root cause of the issue in M96 / M97 doesn't mean later engines will never borescore, it just makes it drastically less likely to happen.

Think the LSPI is more usually thought to apply to downsized turbo DFI lumps, as opposed to an NA engine like this. Scoring in the 9A1 has been attributed to clearances / partial seizures. More here, with pics!: http://911uk.com/viewtopic.php?t=128713 Does happen, but it's uncommon enough not to be a significant worry.

Just as likely to happen to N/A DFi engines, though there was a very specific problem with early 9A1 engines, primarily due to issues caused in the crankcase casting process.

I followed a car out onto warmup laps at a PCGB Silverstone track day. On lift off, at the bottom of hanger, there were huge, bright orange flames out of the exhausts and smoke. The driver did not know. it was pretty alarming, because I did wonder if the lump was about to let go altogether. I went and saw him in the pits to let him know ASAP and he retired the car. Thought it better for him and everyone else that I told him!

I sold my 997.1 C4S “low miles” last year to a chap that had already spent a small fortune on PPI’s. He was so chuffed that it showed no signs of scuffing that he almost kissed the guy who’d now completed 4 inspections for him. He took the car there and then, transferred the money and as he drove off into the evening sunshine it was only then that I felt like I’d been car jacked and on the off chance I hadn’t what would I replace it with? Naturally I looked towards a newer more robust 911, one that was bomb proof. I even used the chap who’d looked over mine some 4 weeks previous with a certain amount of scepticism as I was sure my engine was about implode as I’d read nothing but horror stories. I too looked at a 997.2 GTS which showed signs of scuffing. Try to imagine the blokes face who’d informed me of this whilst reminding me about mine. I passed it off and thought 997.2 C4S was the natural progression so off I went again, only I could find 2 .2 997’s that allegedly don’t suffer from the .1’s Achilles heel ! It was only then that I realised I’d sold the only car I said I was never going to sell because I’d believed stories made up on the internet. I know now that not all .1’s suffer from Bore Scoring, And not all .2’s are exempt from the same fate. Edited by ArchiesDad on Thursday 31st March 23:18

ArchiesDad said: II even used the chap who’d looked over mine some 4 weeks previous Might I ask who you used for the inspection?