AWDGuy

unfortunately my thoughts are scored cylinders. get it scoped.

Ahsai

Sorry to hear that. The AOS reading even at 8" of water would not cause such high oil consumption and your mechanic was likely wrong. Your symptoms scream bore scoring like AWDGuy said.

DASC4S

As I put in motion to see a different local indy shop on this, is there a definitive discussion on the bore scoring issue on rennlist or renntech? My searches so far are coming up with mentions of it in the context of troubleshooting (like this thread) but not a comprehensive discussion as there is in several places on something like the IMS bearings (root cause, design defects, manifestations of the issues, consequences, remedies, false gods to pray to, etc). Would like to learn more in parallel to whatever a tech may tell me.

Thanks.

wildbilly32

Water temp was near the 8 of 180 F and the vacuum was measured at 4. So AOS looks good.

AWDGuy

lots of threads discussing this and the causes. not everyone agrees on route cause. some will say it's the material in the block allowing the cylinders to taper and eventually oval to the point that scoring starts. some say it's because these cars are driven in the cold. Porsche says it's crappy maintenance.

a car costing 100k + shouldn't experience scored cylinders at 60k mile mark. that's *my* opinion of course and why I would never buy a porsche again - even new 9A1 and Cayennes suffer from this manufacturer fault. it's ridiculous.

find a shop that will remove the sump plate and scope from there. it isn't a hard job to do at all....shouldn't be more than 1 hour labor.

AWDGuy

...and I'm sorry man

re-reading this thread brings up a lot of memories how my 996 purchase went down.

so many lessons learned.

DASC4S

So out of curiosity, where do scored cylinders ultimately lead to? I imagine:
- you lose compression and the combustion process takes a hit causing multiple issues (loss of power, emissions issues, NVH)
- maybe the scoring over time spits out more particles and those start to find there way into other moving parts in the engine causing premature failure
- obviously burning more oil
- local overheating in the cylinders causing other issues?
- what else?

I guess I'm looking to understand how this might ultimately lead to my engine euthanizing itself. Does the engine basically start to eat itself alive?

Not saying I'm going to take risks, especially since the root cause of my issue is still not confirmed. Just learning.

Thanks

Disregard - I'm starting to piece it together
https://rennlist.com/forums/996-foru...cylinders.html

Chris(MA)

sorry you won the reverse 996 lottery

AWDGuy

a few here just add oil and keep driving it. I know for a fact there's a c4s going around ottawa now that has severe scoring in all cylinders on bank 2 and all he does is add oil.

I could have kept driving mine....just had to keep adding oil every gas fill. there was very little performance lost as i was still tracking it and pulling on cars that had some pretty good HP.

but yeah, the engine is basically eating away at itself at this point. I felt it was only a matter of time before something really bad happened and I was better to fix the core I had than to source another when things went horribly wrong.

out of the failures to have, this one (scored cylinders) is the one you want. most other modes of failure take out your block which adds to the rebuild costs significantly.

DASC4S

I need to pass emissions inspection here in MD in the next 30 days, so that may dictate what I do or don't do and how soon. I'll get it checked in the meantime, ideally tomorrow just for the sanity of definitively knowing whats going on. I saw what Flat6 Innovations was saying in the linked post, and understand the extreme end. I also saw people posting experiences like you describe: drive it, feed it oil, monitor it, and plan for the work someday.

AWDGuy

I'm not sure what is included in your emissions testing but we had the sniffer test here in Ontario at the time and I passed

with flying colors.

here is a pic of my scored cylinders.



I tracked and emission tested the car like that.
https://youtu.be/U65YkjOObRo
here I am tracking it with scored cylinders. she burnt less oil on the track than regular driving!

Vincent713

I was told by a mechanic that these cylinders have sleeves in them? About how much for a scored cylinder job?

AWDGuy

doing it yourself cost me about $18k CDN.

Everything inside the motor that could be replaced, was.

DASC4S

Finally got the videos converted. The one with the engine bay is with the car cold, just started right after I did the AOS manometer test. The one of the underside is after it's been fully warmed up.

AWDGuy

can't play them from my phone. can you upload to youtube. ?