Cay_PI

Yes, I know about the new coated camshafts. But I refer to the cylinder heads (not the valvetrain, the heads.. - I'm not a native english speaker... hope you know what I mean ). I know there was a chnage from maybe March '15 (additional oil sprayers), used in the latest F and in the G engines. Is there another revision?

Does someone have a "revision-timeline"? The rockers are 3rd revision today I think... camshafts 2nd? Heads 2nd? Rings 2nd or 3rd? Oil pump and filter 2nd?

Wooly1

I recently had two different "reduced power, OK to Drive, Service Immediately" CEL's on cold start ups on my 15 GT3 with an (F) engine. Dealer turned off fault light and advised me to drive it and see if it happened again. I have since taken it to the track a couple times with no issue. I took it into the dealer this week to have it checked out more thoroughly and they just called and said they are replacing the starting coils and spark plugs. I've followed this thread some from the beginning and remember reading something about the coils but can't find it now. Would love some feedback and advice on the situation. Macca?

Macca

Wooly. You may get luck and it's a faulty cool pack. OrthoJoe had this and is still driving his original F engine some time later. The car is very sensitive to plug and coil condition - probably something to do with it reaching 9000 rpm.

All that said a cool pack and plug change for a number of folk here has just been a precursor to the misfire issue with worn rockers and cams. David from San Diego comes to mind. I think often new coil packs and plugs mask the timing issue - so run it hard at the track for a few more days and see what shakes out...

Macca

Cay. You are right on the money! Must have been reading this thread very well. We have no timeline because in PET many of the revisions are noted by the exact same part number with no mention of what engine serial number they started from. For example rockers - here we only believe there have been three visions from what we have been told by service advisors or companies like DMS who have ordered the new parts and compared with the old.

Your list of what had been changed is consistent with mine.

HOWEVER - earlier in the post you will find some pictures by Chris in Europe that show his new heads being fitted with DLC cams. They have a revised part number from the later G heads. I annoy determine if this part number is specific to a "service kit" (ie only given to the heads used as replacements for people with this problem), or intact are these a newer head with an altered design? PET sheds no light but is always a little out of date, so possibly these are a new head design since the G engine and are part of the package with DLC cam fitted to 911R and later build 991 RS. It's hard to say right now.

One thing that makes me wonder us the rumour that the new 991.2 GT3 engine as a "new oiling system" etc.

Some believe the 991.2 GT3 engine will have significant revisions. I am skeptical. Of course compared with the prior MA175 3.8l engine launched in Geneva 2013 yes there are huge revisions. We had the rod bolt recall, then all the revisions you note. The engine has changed SIGNIFICANTLY over 3 years and with a capacity change for 991.2 GT3 you could say it's MUCH CHANGED from the 991 GT3.

I personally believe the latest 991.2 GT3 Cup engine is essentially the engine we see in the 911R with maybe some small changes to the heads and oiling at the very most. I think the DLC coated cams they are confident are the last part of the puzzle in conjunction with the heavily reduced redline (8500).

The Cup engine is less stressed than the 992 GT3 engine. It has the beefier crank from the RS I would imagine, a lower redline and hp output and DLC everything!

The fact the new Cup engine makes 5% more toque than the RS is likely due to the car having a "race exhaust" with freer flow cat converters and ECU tuning that is not toque limited for emissions. DMS can tell you all about this - they have delved into the ECU can can liberate that torque on a 991 GT3 and RS but it means new headers and an ECU flash to recover all the torque left on the table that the Cup car has "found".

Much of the above is my personal view, but having been contacted by many, spoken to many and studied much I feel my view on this is fairly reasonable. I know at Geneva 2017 AP will tell us the marketing spin in the new car but I really want to see through this until real technical data has been presented. I have a bet each way in this horse race so I'm not biased but u am skeptical after all we have been through...

By the way your English looks better than mine!!

bronson7

What instructions or comments did the dealer have for you? Please keep us posted. Thank you.

Match-Lave

How many miles do you have on your the car?

Cay_PI

Thanks Macca, I read every single page in this thread. My engine is a F from April 2015. It has the 2nd revision of heads I think (engine no > 03047) but referring to my dealer its the 1st revision of the oil filter used. I guess the new head design is for better oiling and one of the magic changes that could resolve the issue (in combination with new coating / modified profile of the followers and cam lobes for reduced friction).

Do we have records of engine failures with motor no. greater than 03047?

Btw. when did they start to build the RS? Was this with beginning of year G or during the F period?

kaboobie

Dear All,


I have been reading every page of this thread. What a rollercoaster ! Anyway, I have an E engine yikes ! It looks like that if I am to keep the car, I should repalce the head of the engine. Is it a straight swap ? How and how many part would I need upgrade the parts to the newest specification ? Some said the new oil pump from the G won't fit the the E engine ? any idea how much ?


Thank you in advance.

Macca

Cay_PI. Unfortunately we haven't been following engine numbers of failed units. We never thought to do that from the beginning. The oil filter did not change until G in July 2015. RS are all G from that same date. The heads certainly helped address the issues I have no doubts, but ultimately they also upgraded the oil pump and filter (may have been precautionary) and once again followers and the DLC cam lobes at a later time so I think we have to accept they had just reason in doing so...

Cay_PI

I simply hope, that upgrading the dlc coated camshafts and finger followers may do the job for late F + early G engines with the newer head. The pump and filter upgrade may be to recover the original headroom after they increased the oil pressure... the pump itself can't be critical for the valvetrain. We will see...

PTGFAR

Macca. Did you intend to say that the oil filter did not change until G in July 2015?

Wooly1

I've got 8,000 miles on the car. I'm supposed to pick it up today or tomorrow so will try to get some more detail from the dealer.

Macca

oops my bad. Typo. I'll correct that sorry!

Macca

Yes I feel this is correct. The pump and fuel filter are nice to have but not critical. They don't address the issue. The Software version of the ECU which adjusts the oil pressure along with the heads, followers and other improvements are more important...

bronson7

Did you follow the recommended break-in?