robmypro

I think they already have a good understanding of the problem, and the cause, and have been making changes to address it. What we do not know is if the latest changes are enough. I would think they have been trying things, putting them in test cars, driving them hard, and tearing them down to inspect. Based on the high rate of failures, I suspect it isn't that hard to reproduce the issue.

levd

One more MY14 GT3 came to limp mode with "engine control failure" during our local track day today.

ipse dixit

That's even more frightening. That Porsche actually knows what the problem is but cannot fix it - or worse yet, will not fix it.

robmypro

Not frightening at all. Comes with the territory when you push the limits. And clearly they ARE fixing it. But it is a dynamic situation. They can't snap their fingers and solve the problem. It is a process. Give it time.

robmypro

If it turns out to be a top end replacement, it would be really good to get some photos. Macca needs more data lol.

Macca

Thanks for the information. If the new cam is not installed till engine 05373 I think it's safe to assume none of the 911 RS delivered in June or July incorporate the change. I suspect the change started with 911 R engines just starting to arrive now....So essentially the bulk of the RS manufactured have the older steel cams....approx 1200 units delivered to date.

Chris. Good to know you got the new heads. I need to check but I'm fairly certain this was a G engine update. According to the bulletins you should essentially have received a full new top end. I'm curious to the part number for the finger followers as the PET lists only one part, same for RS and GT3. The new head has additional oil squirters for lubrication.

What you have now is essentially a v2.0 engine same as fitted to latest 911R! You are the first we know with these latest updates. I'm sure they will serve you well so go out there and drive it hard..,

P.S. I personally wonder if the whole "reduced rpm" thing was simply a response to PAG not knowing exactly where the issue lay and once they can be certain they have nailed the fix (this could take another 18 months at least) they will be more generous for the redline on the 992 gen GT3 assuming it's NA? If this is a lubrication issue between cam lobe and finger follower and to do with durability of coatings etc then I doubt 400 is going to make a huge difference.

Obviously they are starting to see the issue on RS which revs under 8700 in most gears, so I don't believe this is a rev headline sensitive issue.

What is fantastic about what we have learned is that there is a fix that can move all our engines forward to v2.0. If that's a permanent fix we will know within a few years and if not then I'm sure developments with 991.2 GT3 will be cross compatible. I think we will find the 991.2 engine essentially identical to the 911R so same family with cross compatible cam shafts, followers and valve train gear...

Macca

Hi Chris this is curious and could be an important clue, but more likely there is a simple explanation.

The latest PET does not show this part number for MA175 or MA176 heads.

The head was change for MA175 from F engine serial 03407 (So essentially starting from beginning of G engine) to part number "9A1 104 911 93". this is the IDENTICAL part number used in the MA176 (RS) engine and no further revision of the heads has taken place for either MA175 or 176 engines according at least to this latest PET.

My "guess" is that the head yopu are looking at is tghe same part but the 911 of the original part number (a generic number) is replaced with 111 (also a generic number in PET speak) to possibly indicate its a replacement part not original to car. the R at the end could be a 3? this would make your number "9A1 104 111 93" so very similar to "9A1 104 911 93". My speculation of course...

SanDiegoDavid

Macca and Chris,

Great work. thank you so much for all the information, a real service to the 991 GT3/RS community here on RL.

I have approximately 1700 miles on my "G" engine on my 2014 GT3. It has been running well until today when I got another CEL, OK to drive on. I drove it back home and swapped it out for my RS. Very frustrating!
May be time to sell!

Jpacione

My June build is G05233

Sean in Texas

How would you like to have THAT job. Here's the key son...we want you to put about 200 track miles/day on her.

Get going

Macca

Thanks for that. Looks like G05373 onwards will be mid July...

David. Yours was a fully G engine transplant right? Is it doing same as with E/F? I.e. Hit 8000 plus rom and it throws the cel and pulls the engine back to 5000 or so? Seems early to have a problem? Let's hope your RS is better luck!

SanDiegoDavid

David. Yours was a fully G engine transplant right? Is it doing same as with E/F? I.e. Hit 8000 plus rom and it throws the cel and pulls the engine back to 5000 or so? Seems early to have a problem? Let's hope your RS is better luck![/QUOTE]

Macca,

Yes, full G engine transplant. The CEL was Engine Control Fault OK to Drive On. It came up this morning while I drove to work, just trying to "exercise" the 3 a little. RPM was low, under 5,000. The engine had been working flawlessly, although its required an unusual amount of oil. What's interesting is there has been no smoke on start up.
More info to come....

Macca

David, thanks for the intel and that's very curious behavior. At this stage my guess is ignition/coils or plugs. It doesnt at first account sound like the issue from before but please keep us updated to progress...


Further delving into the latest PET brings to light some interesting facts relating to why earlier 991 GT3 MA175 engines smoke more than later but still leaves a few details unanswered.

It appears there have been three piston revisions for these cars and two ring revisions, with one assumes the last G engines incorporating the third piston revision (last three digits 097 moving on from 096 moving on from 095) and second ring revision.

This would explain reduced oil seepage at static causing the puff of smoke on start up, but is not particularly material I should think in the finger follower/cam wear issue...

SmokinGTS

Check your engine oil cap, if it is not tight it will throw a cel light.

Chris3963

Here is a zoom of the part no. on the cylinder head. It's a bit blurry, but to my eyes it looks like 9A1.104.111.9R.....it doesn't look like 9A1.104.911.93 to me.....but take a look and see what you think it is. Of course, this could be a complete red herring.