ZuffenZeus

Good point. I think since the 9A1 based cars are now way out of warranty, they're seeing their way into the hands of DiYrs and independent shops. This will reveal more of the good, bad, and ugly with the Alusil closed deck cylinder technology. For what it's worth, SUMEbore cylinder technology in post 2019 Porsche cars is showing to be as durable as Nikasil plating. Flat 6 Innovations and LN Engineering are doing tests to see if this will be a solid replacement for Nikasil. Time will tell.

groovzilla

Again, IMO purchasing a higher mileage 997 with Bore Scope Inspection performed showing clean cylinders & excellent PPI seems to be a smart approach to buying a 997 these days especially a buyer on a tight budget.
I'd buy a clean cylinder 90-110K example over a 30K-70K example all day. And money isn't an issue for me however I like peace of mind and being smart with my expenditures.
Why ****-away $25K on a rebuild when it is an easy simple process to avoid?

Just my opinion after 36 years of Porsche ownership and past 7 years of 997 S/C4S & C4 ownership.

Whisperjet

Yeah I have read about the 997.2s and would be interested in them except that they are really more than I want to spend on a (any) car. In addition, I've read as Petza914 and Carreralicious mention, about a few 9A1 engines having a different but no less worrying bore scoring. From what I've read it comes on more suddenly as well?

After talking to a car buddy of mine I think I am close to talking myself out of a 997.1. I want to buy this as a fun purchase, not something that adds anxiety to my life. That being said, if I was to PPI this car and bore scope it and everything came back clean, to hopefully keep bore scoring at bay I should:

• Install an LN Engineering thermostat
• Use a high quality oil
• Change the oil frequently
• Send oil samples to Blackstone for analysis & cut open the oil filter
• Make sure the car is always warm (200F oil temp) before going above 3000 RPM
• Clean out radiators

Am I missing anything there?

Thanks for the responses by the way. I haven't totally given up on a P-car yet.

Ericson38

Is this process similar to what Audi is doing with the EA389 and EA839 engines?

Atmospheric plasma spraying (APS)

To create a sufficiently robust iron running surface, the cylinder walls are first roughened with a special milling tool which cuts a dovetailed pattern into the cylinder. The resulting undercuts ensure that the APS coating adheres properly. A rotating plasma torch is then inserted into the cylinder. An arc discharge is used to create a plasma into which a powdered coating material is blown using compressed air. The powder melts and is sprayed onto the rough cylinder wall. There it solidifies and fills the undercuts thus creating a wear layer. A layer of iron (roughly equivalent to 100Cr6 bearing steel) is applied in several layers in approximately 30 seconds. The final thickness is approximately 150 micrometers. (One micrometer equals one millionth of a meter.)

silver_tt

Same thing -- the technology is being used in several VWAG brands in newer, high end engines. SUMEBore coatings are applied by a powder-based air plasma spraying (APS) process.

silver_tt

The 9A1 is not bulletproof. It uses the same cylinder technology as its water cooled non-Mezger predecessors that are prone to bore scoring and there's a reason Porsche ditched it for SUMEbore coatings in the newer engines.

Prairiedawg

This is true, there have been enough anecdotal failures documented here that I wouldn't call them bulletproof. I'm starting to think warm or cold weather cars makes no difference. As these cars get miles on them, they'll make themselves known.

bgoetz

I wouldn’t own a 997 if it were my only car

Having owned lots of Japaneese cars and German cars, they are not the same. The build and quality of the German car is noticeably better which translates to the ride and experience. If I had one car to daily it would be an RS5. I currently have a tuned S4 and will probably go that route, although the S4 is a beast. If you want something smaller, more nibble try an RS3 or an M2, although IMO the fit and finish of the Audi is closer to a Porsche

groovzilla

Mercedes Sedans and SUV's are superior to Japanese. Much better suspension/steering/brakes and overall comfort but you pay for it
And personally our Mercedes SUV and sedan's are diesel which are great MPG and reliability.

I wouldn't use a 997 for a daily driver but I'm older at 63 and like the SUV comfort for most of my driving. Funny how I used to think my bones and muscles would never ache.
Enjoy the hunt. ...and make sure you get thorough PPI and Bore scope Inspection for peace of mind.

Wonderdan

Man it will be a sad day when I have to tell my wife that the engine fix on the Porsche was $65k… as long as no one here tells her what the new 4.1 on the back means

Bruce In Philly

I am not sure of this. The M96/M97 engines (997.1) used an open deck design with Lokasil lining, and the 9A1 used a closed deck design with different liner casting call Alusil... and of course there is no IMS in the 9A1. Even the pistons, rings, and crank bearing systems, the oiling system of pumps and savaging... all are very different. The 9A1 is a very different block.

https://myemail.constantcontact.com/...id=KpujerQy6iw

I have some documents that describe the differences in more detail.... PM me if you want some long reads.

Peace
Bruce in Philly (now Atlanta)

bgoetz

The open deck really only contributes to d-chuck, which isn’t nearly as frequent of an issue. No IMS = longer chain, Alusil has many documented issues and becoming more frequent, the DFI causes issues as well. The reality is that while the 9A1 is maybe slightly more reliable it is far from bullet proof and time will tell how much better it is than the M97. How much of a $ premium that is worth depends on the buyer.

silver_tt

No IMS but ridiculously tight piston to cylinder clearances and the pistons can literally seize in addition to bore scoring. Also agree with the points bgoetz raised.

LeNoah

So, all of this being said, what is the earliest year/version 911 that would be free of bore score issues? 992.1? 2017?

silver_tt

Starting with 991.2 they have SUMEbore